INTRODUCTION
Human anatomy is the science which deals with the structure of the human body. The term, ‘anatomy’, is derived from a Greek word, ‘anatome’, meaning cutting up. The term ‘dissection’ is a Latin equivalent of the Greek anatome. However, the two words, anatomy and dissection, are not synonymous. Dissection is a mere technique, whereas anatomy is a wide field of study. Anatomy forms firm foundation of the whole art of medicine and introduces the student to the greater part of medical terminology. ‘Anatomy is to physiology as geography is to history, i.e. it describes the theatre in which the action takes place.’
LANGUAGE OF ANATOMY
Various positions, planes, terms in relation to various regions and movements are described.
Positions
- Anatomical position: When a person is standing straight with eyes looking forwards, both arms by the side of body, palms facing forwards, both feet together, the position is anatomical position.
- Supine position: When a person is lying on her/his back, arms by the side, palms facing upwards and feet put together, the position is supine position.
- Prone position: Person lying on his/her face, chest and abdomen is said to be in prone position.
- Lithotomy position: Person lying on her back with legs up and feet supported in straps. This position is mostly used during delivery of the baby.
Planes
- A plane passing through the centre of the body dividing it into two equal right and left halves, is the median or midsagittal plane. Plane parallel to median or midsagittal plane is the sagittal plane.
- A plane at right angles to sagittal or median plane which divides the body into anterior and posterior halves is called a coronal plane.
- A plane at right angles to both sagittal and coronal planes which divides the body into upper and lower parts is called a transverse plane.
Terms Used in Relation to Trunk
- Ventral or anterior is the front of trunk.
- Dorsal or posterior is the back of trunk.
- Medial is a plane close to the median plane.
- Lateral is plane away from the median plane.
- Proximal/cranial/superior is close to the head end of trunk.
- Distal/caudal/inferior is close to the lower end of the trunk.
- Superficial is close to skin/towards surface of body.
- Deep away from skin/away from surface of body.
- Ipsilateral on the same side of the body as another structure.
- Contralateral on opposite side of body from another structure.
- Invagination is projection inside.
- Evagination is projection outside.
Terms Used for Describing Vessels
- Arteries carry oxygenated blood away from the heart, with the exception of the pulmonary and umbilical arteries which carry deoxygenated blood. Arteries resemble trees because they have branches (arterioles).
- Veins carry deoxygenated blood towards the heart, with the exception of the pulmonary and umbilical veins which carry oxygenated blood. Veins resemble rivers because they have tributaries (venules). Veins have valves to allow unidirectional flow of blood.
- Capillaries are networks of microscopic vessels connecting arterioles to venules.
- Anastomosis is a precapillary or postcapillary communication between the neighboring vessels.
Terms Used in Clinical Anatomy
- The suffix, ‘-itis’, means inflammation, e.g. appendicitis, tonsillitis, arthritis, neuritis, dermatitis, etc.
- The suffix, ‘-ectomy’, means removal from the body, e.g. appendectomy, tonsillectomy, gastrectomy, nephrectomy, etc.
- The suffix, ‘-otomy’, means to open and then close a hollow organ, e.g. laparotomy, hysterotomy, cystotomy, cystolithotomy, etc.
- The suffix, ‘-ostomy’, means to open hollow organ and leave it open, e.g. cystostomy, colostomy, tracheostomy, etc.
- The suffix, ‘-oma\means a tumor, e.g. lipoma, osteoma, neurofibroma, hemangioma, carcinoma, etc.
- Puberty: The age at which the secondary sexual characters develop, being 12–15 years in girls and 13–16 years in boys.
- Symptoms are subjective complaints of the patient about his disease.
- Signs (physical signs) are objective findings of the doctor on the patient.
- Diagnosis: Identification of a disease, or determination of the nature of a disease.
- Prognosis: Forecasting the probable course and ultimate outcome of a disease.
- Pyrexia: Fever.
- Lesion: Injury, or a circumscribed pathologic change in the tissues.
- Inflammation is the local reaction of the tissues to an injury or an abnormal stimulation caused by a physical, chemical, or biologic agent. It is characterized by: (a) Swelling; (b) pain; (c) redness; (d) warmth of heat; and (e) loss of function.
- Edema: Swelling due to accumulation of fluid in the extracellular space.
- Thrombosis: Intravascular coagulation (solidification) of blood.
- Embolism: Occlusion of a vessel by a detached and circulating thrombus (embolus).
- Hemorrhage: Bleeding which may be external or internal.
- Ulcer: A localized breach (gap, erosion) in the surface continuity of the skin or mucous membrane.
- Sinus: A blind track (open at one end) lined by epithelium.
- Fistula: A track open at both the ends and lined by epithelium.
- Necrosis: Local death of a tissue or organ due to irreversible damage to the nucleus.
- Degeneration: A retrogressive change causing deterioration in the structural and functional qualities. It is a reversible process, but may end in necrosis.
- Gangrene: A form of necrosis (death) combined with putrefaction.
- Infarction: Death (necrosis) of a tissue due to sudden obstruction of its artery of supply (often an end-artery).
- Atrophy: Diminution in the size of cells, tissue, organ, or a part due to loss of its nutrition.
- Dystrophy: Diminution in the size due to defective nutrition.
- Hypertrophy: Increase in the size without any increase in the number of cells.
- Hyperplasia: Increase in the size due to increase in the number of cells.
- Hypoplasia: Incomplete development.
- Aplasia: Failure of development.
- Paralysis: Loss of motor power (movement) of a part of body due to denervation or primary disease of the muscles.
- Hemiplegia: Paralysis of one-half of the body.
- Paraplegia: Paralysis of both the lower limbs.
- Monoplegia: Paralysis of any one limb.
- Quadriplegia: Paralysis of all the four limbs.
- Anesthesia: Loss of the touch sensibility.
- Analgesia: Loss of the pain sensibility.
- Thermanesthesia: Loss of the temperature sensibility.
- Hyperesthesia: Abnormally increased sensibility.
- Paresthesia: Perverted feeling of sensations.
- Coma: Deep unconsciousness.
- Tumor (neoplasm): A circumscribed, noninflammatory, abnormal growth arising from the body tissues.
- Benign: Mild illness or growth which does not endanger life.
- Malignant: Severe form of illness or growth, which is resistant to treatment and ends in death.
- Carcinoma: Malignant growth arising from the epithelium (ectoderm or endoderm).
- Sarcoma: Malignant growth arising from connective tissue (mesoderm).
- Cancer: A general term used to indicate any malignant neoplasm which shows invasiveness and results in death of the patient.
- Metastasis: Spread of a local disease (like the cancer cells) to distant parts of the body.
- Convalescence: The recovery period between the end of a disease and restoration to complete health.
- Therapy: Medical treatment.
SKELETON
Skeleton includes bones and cartilages. It forms the main supporting framework of the body, and is primarily designed for a more effective production of movements by the attached muscles.
Functions
- Bones give shape and support to the body, and resist any forms of stress.
- These provide surface for the attachment of muscles, tendons, ligaments, etc.
- These serve as levers for muscular actions.
- The skull, vertebral column and thoracic cage protect brain, spinal cord and thoracic viscera, respectively.
- Bone marrow manufactures blood cells.
- Bones store 97% of the body calcium and phosphorus.
- Bone marrow contains reticuloendothelial cells which are phagocytic in nature and take part in immune responses of the body.
- The larger paranasal air sinuses affect the timber of the voice.
Classification of Bones
According to Shape
- Long bones: Each long bone has an elongated shaft (diaphysis) and two expanded ends (epiphyses) which are smooth and articular. The shaft typically has 3 surfaces separated by 3 borders, a central medullary cavity, and a nutrient foramen directed away from the growing end. Examples:
- typical long bones like humerus, radius, ulna, femur, tibia and fibula;
- miniature long bones have only one epiphysis like metacarpals, metatarsals and phalanges; and
- modified long bones have no medullary cavity like clavicle.
- Short bones: Their shape is usually cuboid, cuneiform, trapezoid, or scaphoid. Examples: tarsal and carpal bones.
- Flat bones resemble shallow plates and form boundaries of certain body cavities. Examples: bones in the vault of the skull, ribs, sternum and scapula.
- Irregular bones: For example, vertebra, hip bone, and bones in the base of the skull.
- Pneumatic bones: Certain irregular bones contain large air spaces lined by epithelium. For example, maxilla, sphenoid, ethmoid, etc. They make the skull light in weight, help in resonance of voice, and act as air conditioning chambers for the inspired air.
- Sesamoid bones: These are bony nodules found embedded in the tendons or joint capsules. They have no periosteum and ossify after birth. They are related to an articular or nonarticular bony surface, and the surfaces of contact are covered with hyaline cartilage and lubricated by a bursa or synovial membrane.For example, patella, pisiform, fabella, etc.Functions of the sesamoid bones are:
- to resist pressure;
- to minimize friction;
- to alter the direction of pull of the muscle; and
- to maintain the local circulation.
- Accessory (supernumerary) bones are not always present. These may occur as ununited epiphyses developed from extra centers of ossification. For example, sutural bones, os trigonum (lateral tubercle of talus), os vesalianum (tuberosity of 5th metatarsal), etc. In medicolegal practice, accessory bones may be mistaken for fractures. However, these are often bilateral, and have smooth surfaces without any callus.
- Heterotopic bones: Bones sometimes develop in soft tissues. Horse riders develop bones in adductor muscles (rider's bones).
Developmental Classification
- Membrane (dermal) bones ossify in membrane (intramembranous or mesenchymal ossification), and are thus derived from mesenchymal condensations. For example, bones of the vault of skull and facial bones.
- Cartilaginous bones ossify in cartilage intracartilaginous or endochondral ossification), and are thus derived from preformed cartilaginous models. For example, bones of limbs, vertebral column and thoracic cage.
- Somatic bones: Most of the bones are somatic.
- Visceral bones: These develop from pharyngeal arches. Examples are hyoid bones, part of mandible and ear ossicles.
Regional Classification
- Axial skeleton includes skull, vertebral column, and thoracic cage.
- Appendicular skeleton includes bones of the limbs.
Structural Classification
- Macroscopically, the architecture of bone may be compact or cancellous.
- Compact bone is dense in texture like ivory, but is extremely porous. It is best developed in the cortex of the long bones. This is an adaptation to bending and twisting forces (a) combination of compression, tension and shear).
- Cancellous or spongy, or trabecular bone is open in texture, and is made up of a meshwork of trabeculae (rods and plates) between which are marrow containing spaces. The trabecular meshworks are of three primary types, namely—(a) meshwork of rods, (b) meshwork of rods and plates, and (c) meshwork of plates (Singh, 1978).
Cartilage
Synonyms
- Chondros (G)
- Gristle
Compare with the terms chondrification, chondrodystrophy, synchondrosis, etc.
Definition
Cartilage is a connective tissue composed of cells (chondrocytes) and fibers (collagen or yellow elastic) embedded in a firm, gel-like matrix which is rich in a mucopolysaccharide. It is much more elastic than bone.
General Features
- Cartilage has no blood vessels or lymphatics. The nutrition of cells diffuses through the matrix.
- Cartilage has no nerves. It is, therefore, insensitive.
- Cartilage is surrounded by a fibrous membrane, called perichondrium, which is similar to periosteum in structure and function. The articular cartilage has no perichondrium, so that its regeneration after injury is inadequate.
- When cartilage calcifies, the chondrocytes die and the cartilage is replaced by bone like tissue.
Types of Cartilage
There are three types of cartilages:
- Hyaline cartilage
- Fibrocartilage
- Elastic cartilage
Comparison between Bone and Cartilage
Bone | Cartilage |
|---|---|
Bone is hard | Cartilage is firm |
Matrix has inflexible material called ossein | It has chondroitin providing flexibility |
Matrix possesses calcium salt | Calcium salts not present |
Bone has rich nerve supply | It does not have nerve supply |
It is vascular in nature | It is avascular in nature |
Bone marrow is present | Bone marrow is absent |
Growth is only by apposition | Growth is appositional and interstitial |
Joints
Definition
Joint is a junction between two or more bones or cartilages. It is a device to permit movements. However, immovable joints are primarily meant for growth, and may permit moulding during childbirth.
There are more joints in a child than in an adult because as growth proceeds some of the bones fuse together, e.g. the ilium, ischium and pubis to form the pelvic bone; the two halves of the infant frontal bone, and of the infant mandible; the five sacral vertebrae and the four coccygeal vertebrae.
Classification of Joints
Structural Classification
- Fibrous joints
- Sutures
- Syndesmosis
- Gomphosis
- Cartilaginous joints
- Primary cartilaginous joints or synchondrosis
- Secondary cartilaginous joints or symphysis
- Synovial joints
- Ball-and-socket or spheroidal joints
- Sellar or saddle joints
- Condylar or bicondylar joints
- Ellipsoid joints
- Hinge joints
- Pivot or trochoid joints
- Plane joints
Functional Classification (According to the Degree of Mobility)
- Synarthrosis (immovable), like fibrous joints
- Amphiarthrosis (slightly movable), like cartilaginous joints.
- Diarthrosis (freely movable), like synovial joints.
Synarthroses
Synarthroses are fixed joints at which there is no movement. The articular surfaces are joined by tough fibrous tissue. Often the edges of the bones are dovetailed into one another as in the sutures of the skull.6
Amphiarthroses
Amphiarthroses are joints at which slight movement is possible. A pad of cartilage lies between the bone surfaces, and there are fibrous ligaments to hold the bones and cartilage in place. The cartilages of such joints also act as shock absorbers, e.g. the intervertebral discs between the bodies of the vertebrae, where the cartilage is strengthened by extra collagen fibers.
Diarthroses or Synovial Joints
Diarthroses or synovial joints are known as freely movable joints, though at some of them the movement is restricted by the shape of the articulating surfaces and by the ligaments which hold the bones together. These ligaments are of elastic connective tissue.
A synovial joint has a fluid-filled cavity between articular surfaces which are covered by articular cartilage. The fluid, known as synovial fluid, produced by the synovial membrane which lines the cavity except for the actual articular surfaces and covers any ligaments or tendons which pass through the joint. Synovial fluid acts as a lubricant. The form of the articulating surfaces controls the type of movement which takes place at any joint.
The movements possible at synovial joints are:
Angular
- Flexion: Decreasing the angle between two bones;
- Extension: Increasing the angle between two bones.
- Abduction: moving the part away from the mid-line.
- Adduction: bringing the part towards the mid-line.
Rotary
- Rotation: Turning upon an axis.
- Circumduction: Moving the extremity of the part round in a circle so that the whole part inscribes a cone.
Gliding
Gliding one part slides on another.
Regional Classification
- Skull type: Immovable.
- Vertebral type: Slightly movable.
- Limb type: Freely movable.
According to Number of Articulating Bones
- Simple joint: When two bones articulate, e.g. interphalangeal joints.
- Compound joint: More than two bones articulate within one capsule, e.g. elbow joint, wrist joint.
- Complex joint: When joint cavity is divided by an intra-articular disc, e.g. temporomandibular joint and sternoclavicular joint.
CARDIOVASCULAR SYSTEM
Cardiovascular system is the transport system of the body, through which the nutrients are conveyed to places where these are utilized, and the metabolites (waste products) are conveyed to appropriate places from where these are expelled. The conveying medium is a liquid tissue, the blood, which flows in tubular channels called blood vessels. The circulation is maintained by the central pumping organ called the heart.
Components
Cardiovascular system is a closed system of tubes made up of the following parts based on their structural and topographical characteristics
- Heart: It is a four-chambered muscular organ which pumps blood to various parts of the body. Each half of the heart has a receiving chamber called atrium, and a pumping chamber called ventricle.
- Arteries: These are distributing channels which carry blood away from the heart.
- They branch like trees on their way to different parts of the body.
- The large arteries are rich in elastic tissue, but as branching progresses there is an ever-increasing amount of smooth muscle in their walls.
- The minute branches which are just visible to naked eye are called arterioles.
- Angeion is a Greek word, meaning a vessel (blood vessel or lymph vessel). Its word derivatives are angiology, angiography, hemangioma and thromboangitis obliterans.
- Veins: These are draining channels which carry blood from different parts of the body back to the heart.
- Like rivers, the veins are formed by tributaries.
- The small veins (venules) join together to form larger veins, which in turn unite to form great veins called venae cavae
- Capillaries: These are networks of microscopic vessels which connect arterioles with the venules.
- These come in intimate contact with the tissues for a free exchange of nutrients and metabolites across their walls between the blood and the tissue fluid.
- The metabolites are partly drained by the capillaries and partly by lymphatics.
- Capillaries are replaced by sinusoids in certain organs, like liver and spleen.
Functionally, the blood vessels can be classified into the following five groups:
- Distributing vessels, including arteries
- Resistance vessels, including arterioles and precapillary sphincters
- Exchange vessels, including capillaries, sinusoids, and postcapillary venules
- Reservoir (capacitance) vessels, including larger venules and veins
- Shunts, including various types of anastomoses.
Types of Circulation of Blood
- Systemic (greater) circulation: The blood flows from the left ventricle, through various parts of the body, to the right atrium, i.e. from the left to the right side of the heart.
- Pulmonary (lesser) circulation: The blood flows from the right ventricle, through the lungs, to the left atrium, i.e. from the right to the left side of the heart.
- Portal circulation: It is a part of systemic circulation, which has the following characteristics:
- The vein draining the first capillary network is known as portal vein which branches like an artery to form the second set of capillaries or sinusoids. For example, hepatic portal circulation hypothalamo-hypophyseal portal circulation and renal portal circulation.
Arteries
Characteristic Features
- Arteries are thick-walled, being uniformly thicker than the accompanying veins, except for the arteries within the cranium and vertebral canal where these are thin.
- Their lumen is smaller than that of the accompanying veins.
- Arteries have no valves.
- An artery is usually accompanied by vein(s) and nerve(s), and the three of them together form the neurovascular bundle which is surrounded and supported by a fibroareolar sheath.
Types of Arteries and Structure
- Large arteries of elastic type, e.g. aorta and its main branches (brachiocephalic, common carotid, subclavian and common iliac) and the pulmonary arteries.
- Medium and small arteries of muscular type, e.g. temporal, occipital, radial, popliteal, etc.
- Smallest arteries of muscular type are called arterioles. They measure 50–100 micron in diameter. Arterioles divide into terminal arterioles with a diameter of 15–20 micron, and having one or two layers of smooth muscle in their walls. The side branches from terminal arterioles are called metarterioles which measure 10–15 micron at their origin and about 5 micron at their termination. The terminal narrow end of metarteriole is surrounded by a precapillary sphincter which regulates blood flow into the capillary bed. It is important to know that the muscular arterioles are responsible for generating peripheral resistance, and thereby for regulating the diastolic blood pressure.
Palpable Arteries
Some arteries can be palpated through the skin. These are—common carotid, facial, brachial, radial, abdominal aorta, femoral, posterior tibial and dorsalis pedis.
Nerve Supply of Arteries
The nerves supplying an artery are called nervi vascularis. The nerves are mostly non-myelinated sympathetic fibers which are vasoconstrictor in function. A few fibers are myelinated, and are believed to be sensory to the outer and inner coats of the arteries. Vasodilator innervation is restricted to the following sites:
- The skeletal muscle vessels are dilated by cholinergic sympathetic nerves.
- The exocrine gland vessels are dilated on parasympathetic stimulation.
- The cutaneous vessels are dilated locally to produce the flare (redness) after an injury. The vasodilatation is produced by the afferent impulses in the cutaneous nerves which pass antidromically in their collaterals to the blood vessels (axon reflex).
Veins
Characteristic Features
- Veins are thin-walled, being thinner than the arteries.
- Their lumen is larger than that of the accompanying arteries.
- Veins have valves which maintain the unidirectional flow of blood, even against gravity. Since the venous pressure is low (7 mm Hg), the valves are of utmost value in the venous return. However, the valves are absent:
- In the veins of less than 2 mm diameter.
- In the venae cavae.
- In the hepatic, renal, uterine, ovarian (not testicular), cerebral, spinal, pulmonary, and umbilical veins.
- The muscular and elastic tissue content of the venous walls is much less than that of the arteries. This is directly related to the low venous pressure.
- Large veins have dead space around them for their dilatation during increased venous return. The dead space commonly contains the regional lymph nodes.
Structure of Veins
Veins are made up of usual three coats which are found in the arteries. But the coats are ill-defined, and the muscle and elastic tissue content is poor. In poorly developed tunica media, the amount of collagen fibers is more than the elastic and muscle fibers. The adventitia is thickest and best developed. The smooth muscle is altogether absent:
- in the veins of maternal part of placenta;
- in the cranial venous sinuses and pial veins;
- in the retinal veins;
- in the veins of cancellous bone; and
- in the venous spaces of the corpora cavernosa and corpus spongiosum.
Blood and Nerve Supply of Veins
The larger veins, like the arteries, are supplied with nutrient vessels called vasa vasorum. But in the veins, the vessels may penetrate up to the intima, probably because of the low venous pressure and the low oxygen tension.
Nerves also are distributed to the veins in the same manner as to the arteries, but are fewer in number.
Factors Helping in Venous Return
- Overflow from the capillaries, pushed from behind by the arteries (vis-a-tergo).
- Negative intrathoracic pressure sucks the blood into the heart from all over the body.
- Gravity helps venous return in the upper part of the body.
- Arterial pulsations press on the venae comitantes intermittently and drive the venous blood towards the heart.
- Venous valves prevent any regurgitation (back flow) of the luminal blood.
Capillaries
Capillaries (capillus = hair) are networks of microscopic endothelial tubes interposed between the metarterioles and 8venules. The true capillaries (without any smooth muscle cell) begin after a transition zone of 50–100 micron beyond the precapillary sphincters. The capillaries are replaced by cavernous (dilated) spaces in the sex organs, splenic pulp and placenta.
Size
The average diameter of a capillary is 6–8 micron, just sufficient to permit the red blood cells to pass through in ‘single file’. But the size varies from organ to organ. It is smallest in the brain and intestines, and is largest (20 micron) in the skin and bone marrow.
Anastomoses
Definition
A precapillary or postcapillary communication between the neighboring vessels is called anastomoses. Circulation through the anastomosis is called collateral circulation.
Types
- Arterial anastomoses is the communication between the arteries, or branches of arteries. It may be actual or potential.
- In actual arterial anastomosis the arteries meet end to end. For example, palmar arches plantar arch, circle of Willis, intestinal arcades, labial branches of facial arteries.
- In potential arterial anastomoses the communication takes place between the terminal arterioles. Such communications can dilate only gradually for collateral circulation. Therefore on sudden occlusion of a main artery, the anastomoses may fail to compensate the loss. The examples are seen in the coronary arteries and the cortical branches of cerebral arteries, etc.
- Venous anastomoses is the communication between the veins or tributaries of veins. For example, the dorsal venous arches of the hand and foot.
- Arteriovenous anastomosis (shunt) is the communication between an artery and a vein. It serves the function of phasic activity of the organ. When the organ is active these shunts are closed and the blood circulates through the capillaries. However, when the organ is at rest, the blood bypasses the capillary bed and is shunted back through the arteriovenous anastomosis. The shunt vessel may be straight or coiled, possesses a thick muscular coat, and is under the influence of sympathetic system.Shunts of simple structure are found in the skin of nose, lips and external ear; in the mucous membrane of nose and alimentary canal; the coccygeal body; the erectile tissue of sexual organs; the tongue; the thyroid gland and sympathetic ganglia. Specialized arteriovenous anastomoses are found in the skin of digital pads and nail beds. They form a number of small units called glomera.Preferential ‘thoroughfare channels ‘are also a kind of shunts. They course through the capillary network. Many true capillaries arise as their side branches.One thoroughfare channel with its associated capillaries forms a microcirculatory unit. The size of the unit is variable from 1–2 to 20–30 true capillaries. The number of active units varies from time to time.
End-Arteries
Definition
Arteries which do not anastomose with their neighbours are called endarteries.
Examples:
- Central artery of retina and labyrinthine artery of internal ear are the best examples of an absolute end arteries.
- Central branches of cerebral arteries and vasa recta of mesenteric arteries.
- Arteries of spleen, kidney, lungs and metaphyses of long bones.
Importance
Occlusion of an end-artery causes serious nutritional disturbances resulting in death of the tissue supplied by it. For example, occlusion of central artery of retina results in blindness.
NERVOUS SYSTEM
Nervous system is the chief controlling and coordinating system of the body. It controls and regulates all activities of the body, whether voluntary or involuntary, and adjusts the individual (organism) to the given surroundings.
Parts of Nervous System
The nervous system is broadly divided into central and peripheral parts which are continuous with each other. Further subdivisions of each part are given.
- Central Nervous System (CNS) includes:
- Brain or encephalon, which occupies cranial cavity, and contains the higher governing centres.
- Spinal cord or spinal medulla, which occupies upper two-thirds of the vertebral canal, and contains many reflex centers.
- Peripheral nervous system (PNS) is subdivided into the following two components.
- Cerebrospinal nervous system is the somatic component of the peripheral nervous system, which includes 12 pairs of cranial nerves and 31 pairs of spinal nerves. It innervates the somatic structures of the head and neck, limbs and body wall, and mediates somatic sensory and motor functions.
- Peripheral autonomic nervous system is the visceral component of the peripheral nervous system, which includes the visceral or splanchnic nerves that are connected to the CNS through the somatic nerves. It innervates the viscera, glands, blood vessels and nonstriated muscles, and mediates the visceral functions.The cerebrospinal and autonomic nervous systems differ from each other in their efferent pathways.
Cell Types of Nervous System
The nervous tissue is composed of two distinct types of cells:
- The excitable cells are the nerve cells or neurons
Neuron
Hach nerve cell or neuron has a cell body or perikaryon, having a central nucleus and Nissl granules in its cytoplasm.
Types of Neurons
Neurons can be classified in several ways.
- According to the number of their processes (neurites) they may be:
- Unipolar, e.g. mesencephalic nucleus;
- Pseudo-unipolar, e.g. sensory ganglia or spinal ganglia
- Bipolar, e.g. spiral and vestibular ganglia and bipolar neurons of retina.
- Multipolar, neurons in cerebrum and cerebellum.
- According to the length of axon, the neurons are classified as:
- Golgi type I neurons, with a long axon; and
- Golgi type II neurons (microneurons), with a short or no axon.
Blood-Brain Barrier
Certain dyes, when injected intravenously, fail to stain the parenchyma of brain and spinal cord, although they pass easily into the non-nervous tissues. However, the same dyes, when injected into the ventricles, enter the brain substances easily. This indicates that a barrier exists at the capillary level between the blood and nerve cells. The possible structures constituting the blood-brain barrier are as follows.
- Capillary endothelium without fenestrations.
- Basement membrane of the endothelium.
- The end feet of astrocytes covering the capillary walls.
The barrier permits a selective passage of blood contents to the nervous tissue, and thus the toxic and harmful substances are ordinarily prevented from reaching the brain.
Reflex Arc
A reflex arc is the basic functional unit of the nervous system which can perform an integrated neural activity. In its simplest form, i.e. mono-synaptic reflex arc, is made up of:
- A receptor, e.g. skin
- A sensory or afferent neuron
- A motor or efferent neuron
- An effector, e.g. muscle.
The complex forms of reflex arc are polysynaptic due to addition of one or more internuncial neurons (interneurons) in between the afferent and efferent neurons.
An involuntary motor response of the body is called a reflex action. The stretch reflexes (tendon jerks) are the examples of monosynaptic reflexes whereas the withdrawal reflex (response to a painful stimulus) is a polysynaptic reflex.
Peripheral Nerves
The nerves are solid white cords composed of bundles (fasciculi) of nerve fibers. Each nerve fiber is an axon with its coverings. The nerve fibers are supported and bound together by connective tissue sheaths at different levels of organization of the nerve. The whole nerve trunk is ensheathed by epineurium, each fasciculus by perineurium, and each nerve fiber by a delicate endoneurium. The toughness of a nerve is due to its fibrous sheaths, otherwise the nerve tissue itself is very delicate and friable.
Spinal Nerves
There are 31 pairs of spinal nerves, including 8 cervical, 12 thoracic, 5 lumbar, 5 sacral, and 1 coccygeal.
Autonomic Nervous System
Autonomic nervous system controls involuntary activities of the body, like sweating, salivation, peristalsis, etc. It differs fundamentally from the somatic nervous system in having:
- The preganglionic fibers arising from the CNS
- The ganglia for relay of the preganglionic fibers
- The postganglionic fibers arising from the ganglia which supply the effectors (smooth muscles and glands).
In contrast, the somatic nerves after arising from the CNS reach their destination without any interruption.
Autonomic nervous system is divided into two more or less complementary parts, the sympathetic and parasympathetic systems.
The sympathetic activities are widespread and diffuse, and combat the acute emergencies.
The parasympathetic activities are usually discrete and isolated, and provide a comfortable environment.
Both systems function in absolute coordination and adjust the body involuntarily to the given surroundings.
Sympathetic Nervous System
- It is also known as ‘thoracolumbar’ outflow because it arises from lateral horn of T1 to L2 segments of the spinal cord.
- The medullated preganglionic fibers (white rami communicantes) arise from the lateral column of the spinal cord, emerge through the ventral rami where the white rami are connected to the ganglia of the sympathetic chain
- Preganglionic fibers relay either in the lateral ganglia (sympathetic chain) or in the collateral ganglia, e.g. the coeliac ganglion. The non-medullated post-ganglionic fibers run for some distance before reaching the organ of supply.
- The adrenal medulla is a unique exception in the body; it is supplied by the preganglionic fibers.
- Sympathetic nerve endings are adrenergic in nature, meaning thereby that noradrenalin is produced for neurotransmission. The only exception to this general rule are the cholinergic sympathetic nerves supplying the sweat glands and skeletal muscle vessels for vasodilatation.
- Functionally, sympathetic nerves are vasomotor (vasoconstrictor), sudomotor (secretomotor to sweat glands), and pilomotor (contract the arrector pili and cause erection of hair) in the skin of limbs and body wall. In addition, sympathetic activity causes dilation of pupil, pale face, dry mouth, tachycardia, rise in blood pressure, inhibition of hollow viscera, and closure of the perineal sphincters. The blood supply to the skeletal muscles, heart and brain is markedly increased. Thus, sympathetic reactions tend to be ‘mass reactions’, widely diffused in 10their effect and that they are directed towards mobilization of the resources of the body for expenditure of energy in dealing with the emergencies or emotional crises (fright, fight, flight).
Parasympathetic Nervous System
- It is also known as craniosacral outflow because it arises from the brain (mixed with III, VII, IX and X cranial nerves) and sacral.
- The preganglionic fibers are very long, reaching right upto the viscera of supply. The ganglia, called terminal ganglia, are situated mostly on the viscera and, therefore, the postganglionic fibers are very short.
- Parasympathetic nerve endings are cholinergic in nature, similar to the somatic nerves.
- Functionally, parasympathetic activity is seen when the subject is fully relaxed. His pupils are constricted, lenses accommodated, face flushed, mouth moist, pulse slow, blood pressure low, bladder and gut contracting, and the perineal sphincters relaxed.In general the effects of parasympathetic activity are usually discrete and isolated, and directed towards conservation and restoration of the resources of energy in the body.
RESPIRATORY SYSTEM
- Respiratory systems allow animals to move oxygen (needed for cellular respiration) into body tissues and remove carbon dioxide (waste product of cellular respiration) from cells.
- ‘Respiration’ is used several different ways:
- Cellular respiration is the aerobic breakdown of glucose in the mitochondria to make ATP.
- Respiratory systems are the organs in animals that exchange gases with the environment.
- ‘Respiration’ is an everyday term that is often used to mean ‘breathing.’
- Consists of the respiratory and conducting zones
- Respiratory zone
- Site of gas exchange
- Consists of bronchioles, alveolar ducts, and alveoli
- Conducting zone
- Provides rigid conduits for air to reach the sites of gas exchange
- Includes all other respiratory structures (e.g., nose, nasal cavity, pharynx, trachea)
- Respiratory muscles—diaphragm and other muscles that promote ventilation.
Major Functions of the Respiratory System
- To supply the body with oxygen and dispose of carbon dioxide
- Respiration—four distinct processes must happen
- Pulmonary ventilation—moving air into and out of the lungs
- External respiration—gas exchange between the lungs and the blood
- Transport—transport of oxygen and carbon dioxide between the lungs and tissues
- Internal respiration—gas exchange between systemic blood vessels and tissues.
Respiratory System is Divided into Two Parts
- Upprer respiratory tract
- Nose
- Paranasal sinuses
- Pharynx
- Lower respiratory tract
- Begins with true vocal cords and extends to alveoli
- Larynx
- Trachea
- Main stem bronchi
- Segmental bronchi
- Subsegmental bronchi
- Bronchioles
- Terminal bronchioles
- Respiratory bronchioles
- Alveolar ducts
- Alveolar sacs
- Alveoli
Structure of the Nose
- The nose is divided into two regions:
- The external nose, including the root, bridge, dorsum nasi, and apex
- The internal nasal cavity
- Philtrum—a shallow vertical groove inferior to the apex
- The external nares (nostrils) are bounded laterally by the alae.
Nasal Cavity
- Lies in and posterior to the external nose
- Is divided by a midline nasal septum
- Opens posteriorly into the nasal pharynx via internal nares
- The ethmoid and sphenoid bones form the roof
- The floor is formed by the hard and soft palates
- Vestibule—nasal cavity superior to the nares
- Vibrissae—hairs that filter coarse particles from inspired air
- Olfactory mucosa
- Lines the superior nasal cavity
- Contains smell receptors
- Respiratory mucosa
- Lines the balance of the nasal cavity
- Glands secrete mucus containing lysozyme and defensins to help destroy bacteria
- Inspired air is:
- Humidified by the high water content in the nasal cavity
- Warmed by rich plexuses of capillaries
- Ciliated mucosal cells remove contaminated mucus
- Superior, medial, and inferior conchae:
- Protrude medially from the lateral walls
- Increase mucosal area
- Enhance air turbulence and help filter air
- Sensitive mucosa triggers sneezing when stimulated by irritating particles.
Functions of the Nasal Mucosa and Conchae
- During inhalation the conchae and nasal mucosa:
- Filter, heat, and moisten air
- During exhalation these structures:
- Reclaim heat and moisture
- Minimize heat and moisture loss
Paranasal Sinuses
- Sinuses in bones that surround the nasal cavity
- Sinuses lighten the skull and help to warm and moisten the air.
Pharynx
- Funnel-shaped tube of skeletal muscle that connects to the:
- Nasal cavity and mouth superiorly
- Larynx and esophagus inferiorly
- Extends from the base of the skull to the level of the sixth cervical vertebra
- It is divided into three regions
- Nasopharynx
- Oropharynx
- Laryngopharynx.
Nasopharynx
- Lies posterior to the nasal cavity, inferior to the sphenoid, and superior to the level of the soft palate
- Strictly an air passageway
- Lined with pseudostratified columnar epithelium
- Closes during swallowing to prevent food from entering the nasal cavity
- The pharyngeal tonsil lies high on the posterior wall
- Pharyngotympanic (auditory) tubes open into the lateral walls.
Oropharynx
- Extends inferiorly from the level of the soft palate to the epiglottis
- Opens to the oral cavity via an archway called the fauces
- Serves as a common passageway for food and air
- The epithelial lining is protective stratified squamous epithelium
- Palatine tonsils lie in the lateral walls of the fauces
- Lingual tonsil covers the base of the tongue.
Laryngopharynx
- Serves as a common passageway for food and air
- Lies posterior to the upright epiglottis
- Extends to the larynx, where the respiratory and digestive pathways diverge.
Trachea
- Flexible and mobile tube extending from the larynx into the mediastinum
- Composed of three layers:
- Mucosa—made up of goblet cells and ciliated epithelium
- Submucosa—connective tissue deep to the mucosa
- Adventitia—outermost layer made of C-shaped rings of hyaline cartilage.
Conducting Zone: Bronchi
- The carina of the last tracheal cartilage marks the end of the trachea and the beginning of the right and left bronchi
- Air reaching the bronchi is:
- Warm and cleansed of impurities
- Saturated with water vapor
- Bronchi subdivide into secondary bronchi, each supplying a lobe of the lungs
Bronchial Tree
- Tissue walls of bronchi mimic that of the trachea
- As conducting tubes become smaller, structural changes occur
- Cartilage support structures change
- Epithelium types change
- Amount of smooth muscle increases
- Bronchioles
- Consist of cuboidal epithelium
- Have a complete layer of circular smooth muscle
- Lack cartilage support and mucus-producing cells
Respiratory Zone
- Defined by the presence of alveoli; begins as terminal bronchioles feed into respiratory bronchioles
- Respiratory bronchioles lead to alveolar ducts, then to terminal clusters of alveolar sacs composed of alveoli
- Approximately 300 million alveoli:
- Account for most of the lungs’ volume
- Provide tremendous surface area for gas exchange.
Respiratory Membrane
- This air-blood barrier is composed of:
- Alveolar and capillary walls
- Their fused basal laminas
- Alveolar walls:
- Are a single layer of type I epithelial cells
- Permit gas exchange by simple diffusion
- Secrete angiotensin converting enzyme (ACE)
- Type II cells secrete surfactant.
Alveoli
- Surrounded by fine elastic fibers
- Contain open pores that:
- Connect adjacent alveoli
- Allow air pressure throughout the lung to be equalized
- House macrophages that keep alveolar surfaces sterile.
Gross Anatomy of the Lungs
- Lungs occupy all of the thoracic cavity except the mediastinum
- Root—site of vascular and bronchial attachments
- Costal surface—anterior, lateral, and posterior surfaces in contact with the ribs
- Apex—narrow superior tip
- Base—inferior surface that rests on the diaphragm
- Hilus—indentation that contains pulmonary and systemic blood vessels.
Lungs
- Cardiac notch (impression)—cavity that accommodates the heart
- Left lung—separated into upper and lower lobes by the oblique fissure
- Right lung—separated into three lobes by the oblique and horizontal fissures
- There are 10 bronchopulmonary segments in each lung
- Base, apex (cupula), costal surface, cardiac notch
- Oblique and horizontal fissure in right lung results in 3 lobes
- Oblique fissure only in left lung produces 2 lobes
- Blood vessels and airways enter lungs at hilus
- Forms root of lungs
- Covered with pleura (parietal becomes visceral).
Blood Supply to Lungs
- Lungs are perfused by two circulations— pulmonary and bronchial
- Pulmonary arteries—supply systemic venous blood to be oxygenated
- Branch profusely, along with bronchi
- Ultimately feed into the pulmonary capillary network surrounding the alveoli
- Pulmonary veins—carry oxygenated blood from respiratory zones to the heart
- Bronchial arteries—provide systemic blood to the lung tissue
- Arise from aorta and enter the lungs at the hilus
- Supply all lung tissue except the alveoli
- Bronchial veins anastomose with pulmonary veins
- Pulmonary veins carry most venous blood back to the heart.
Pleurae
- Thin, double-layered serosa
- Parietal pleura
- Covers the thoracic wall and superior face of the diaphragm
- Continues around heart and between lungs
- Visceral, or pulmonary, pleura
- Covers the external lung surface
- Divides the thoracic cavity into three chambers
- The central mediastinum
- Two lateral compartments, each containing a lung.
GASTROINTESTINAL SYSTEM
- Gastrointestinal (GI) tract [alimentary canal] a continuous muscular digestive tube
- Digests:
- Breaks food into smaller fragments
- Absorbs:
- Digested material is moved through mucosa into the blood
- Eliminates:
- Unabsorbed and secreted wastes.
- Includes:
- Mouth, pharynx and esophagus
- Stomach
- Small intestine
- Large intestine
- Accessory digestive organs—teeth, tongue, gallbladder, salivary glands, liver and pancreas.
GI Blood Supply
- Blood supply—about 25% of cardiac output
- Celiac trunk (hepatic, splenic and gastric branches which serve the liver, spleen and stomach)
- Celiac trunk (superior and inferior mesenteric branches serve small and large intestine).
Histology
- GI tract wall has four layers:
- Mucosa
- Submucosa
- Muscularis Externa
- Serosa or Adventitia
- Mucosa: The epithelial membrane that lines the GI tract from mouth → anus.
- Secretes mucous, digestive enzymes and hormones
- Absorbs nutrients
- Protects from disease and from the GI contents
- Mucosa; three layers:
- Epidermis
- Lamina propria (loose connective tissue— contain capillaries and some elements of MALT)
- Muscularis mucosa
- Submucosa: Moderately dense CT with blood, nerve, lymph vessels and lymphoid follicles; rich in elastic fibers
- Muscularis externa: Smooth muscle
- Responsible for peristalsis and segmentation
- Circular layer
- Longitudinal layer
- Sphincters: In some areas the circular layer thickens; act as valves
- Serosa of intraperitoneal organs = visceral peritoneum
- Esophagus has an outer covering of fibrous connective tissue = adventitia
- Retroperitoneal organs: Visceral serosa on the surface facing the peritoneal cavity and adventitia on the surface facing the body wall.
Nerves
- Intrinsic (local): Short reflex
- Submucosal nerve plexus: Regulates glands and mucosal muscle
- Myenteric plexus: Controls GI wall and GI motility
- Extrinsic (CNS): Long reflex
- Parasympathetic NS: Enhances gut motility and secretion
- SNS: Inhibits gut motility and secretion
Functional Anatomy: Mouth
- Mouth: Lips, palate, and tongue
- Mouth cavity = Buccal cavity
- Lips: Extend from inferior margin of the nose to the superior margin of the chin. Red area = red margin, is poorly keratinized and lacks sweat or sebaceous glands.
- Palate:
- Hard palate: Rigid surface against which food is forced in chewing
- Soft palate: Muscular structure that rises and blocks off the nasopharynx during swallowing
- Tongue: Muscular tentacle composed of interlaced muscle fibers that grips and repositions food, mixes food with 14saliva and compresses food to form a food bolus, prior to swallowing.
- Filiform papillae: Rough surface
- Fungiform papillae: House taste buds
- Circumvallate papillae: House taste buds,
- Foliate papillae: Posterolateral; taste buds
- Salivary glands: Intrinsic and extrinsic
- Intrinsic glands: Scattered throughout the buccal cavity mucosa
- Extrinsic glands: Supply most of the saliva; outside buccal cavity and supply secretions via ducts:
- Parotid
- Submandibular
- Sublingual
- Composition of saliva:
- 97–99.5% H2O
- Electrolytes: pH 6.75–7.0
- Amylase (digestive enzyme)
- Proteins: Mucin, lysozyme, and IgA
- Protection from microbes by saliva:
- IgA: Immunglobulins in secretions
- Lysozyme: Bacteriostatic (inhibits bacterial growth)
- Cyanide
- Defensins: Local antibiotic activity and when activated promote chemotaxis by WBCs
- Normal flora: Convert salivary components to nitrates then to NO. NO is toxic and bacteriocidal
- Control of salivation:
- Continuous baseline secretory activity
- With food ingestion, salivation increases dramatically
- Parasympathetic NS: Chemoreceptors and pressoreceptors stimulate salivatory nuclei to increase salivation
- Teeth:
- Structures
- Crown: Exposed above gingiva (gum)
- Root: Anchored by periodontal ligament to the bone by a fibrous joint (gomphosis).
Throat and Esophagus
- Pharynx: Oropharynx and laryngopharynx; muscular wall propels food to the esophagus.
- Esophagus:
- Muscular 25 cm tube from laryngopharynx to stomach
- Passes through the diaphragm at the esophageal hiatus
- Gastroesophageal (cardiac) sphincter: A physiologic sphincter that helps keep esophagus closed when empty
- Wall has all 4 GI tract tunics:
- Epithelial layer changes at the junction with the stomach from stratified squamous epithelium to simple columnar epithelium
- Esophageal mucous glands lubricate food bolus
- Muscularis externa
- Superior 1/3 of muscularis externa is skeletal muscle
- Middle 1/3 is mixed skeletal and smooth
- Lower 1/3 is smooth muscle
- Adventitia: External covering.
Stomach
- Cardiac region: Narrow, receives food bolus
- Fundus: Bulge that extends superolaterally to the cardia, reaches the diaphragm
- Body: Mid-portion
- Pyloric antrum: Funnel shaped portion narrows to form the
- Pyloric canal > pylorous > pyloric sphincter > small intestine
- Rugae
- longitudinal mucosal folds
- Volume about 4L
- Gastric glands secrete gastric juices
- Mucous neck cells: In the duct portion
- Parietal cells: Mid portion secrete HCl and intrinsic factor for B12 absorption
- Chief cells: Base of gland; secretes pepsinogen a precursor molecule to pepsin (an enzyme that digests protein)
- Enteroendocrine cells: Secrete multiple hormonal products
- Gastrin, histamine, endorphins, serotonin, cholecystokinin, and somatostatin, which influence several digestive system organs
- Mucosal barrier: Protects the stomach from its own secretions
- Viscous mucous overlies a thick coating of HCO3 (rich mucous)
- Tight junctions between epithelial cell PM of glandular cells are impermeable to HCl
- Epithelium is replaced every 3–6 days.
Digestive Processes (Stomach)
- Acts as a holding vessel for ingested food
- Participates in mechanical and chemical digestion
- Propulsion: Delivers its product (chyme) to the small intestine
- Protein digestion: HCl denatures protein
- HCl activates pepsinogen to pepsin
- Pepsin breaks peptide bonds of proteins
- Rennin: An enzyme that breaks down casein (milk protein) secreted in infants
- Intrinsic factor: Required for Vit. B12 absorption (needed to mature RBC);
- Absence of B12 results in pernicious anemia.
Small Intestine: Gross Anatomy
- 6–7 m long: From pyloric sphincter to the ileocecal valve
- Three subdivisions:
- Duodenum
- Jejunum
- Ileum
- Duodenum:
- Curves around the pancreatic head (~25 cm long)
- Contains the hepatopancreatic ampulla: formed by the merger of the bile duct and the pancreatic duct.
- Hepatopancreatic sphincter controls admission of bile and pancreatic enzymes to the duodenum
- Duodenum is retroperitoneal
- Duodenenal regulation of gastric emptying: Feedback mechanisms monitor the contents being delivered from the stomach
- High fat content
- Low pH (high acidity)
- Hypertonicity (high osmolality)
- All result in decreased stomach emptying.
- Jejunum: Extends from duodenum to ileum (~2.5 m long)
- Ileum: From jejunum to ileocecal valve (~3.6 m long)
- Jejunum and ileum function in absorption;
- Intraperitoneal
- Suspended from mesentery whose veins and lymph vessels carry nutrients away from small intestine.
Small Intestine Wall
- Cell types:
- Mostly absorptive cells
- Goblet (mucous) cells increase in number as the small intestine progresses
- Enteroendocrine cells
- T-lymphocytes
- Intestinal crypts with cells that secrete intestinal juice and contain Paneth cells that secrete protective lysozyme (antibacterial)
- Peyer's patches: lymphoid follicle in submucosa
- Brunners glands (duodenum) secrete HCO3− rich mucous to increase the pH of chyme
- Villus epithelium is replaced every 3–6 days
- Intestinal Juice: Isotonic with blood plasma, slightly alkaline, low enzyme content.
Liver and Gallbladder
Liver produces bile (fat emulsifier) that is stored in and concentrated by the gallbladder.
- Largest gland
- Four lobes
- Falciform ligament
- Mesentery supports liver from diaphragm and anterior body wall
- Separates right (R) and left (L) lobes
- Round ligament fibrous remnant of umbilical vein
- Blood supply
- Hepatic artery and hepatic portal vein
- Bile
- drains from biliary ducts to common hepatic duct which fuses with cystic duct from gallbladder to form the bile duct
- Composition of bile: Alkaline solution: Bile salts, bile pigments, cholesterol, fats and phospholipids
- Bile salts and phospholipids participate in fat absorption
- Bile salts are conserved by enterohepatic circulation
- Reabsorbed in the ileum
- Return to liver in hepatic portal blood
- Re-secreted by the liver
- Bile pigments and bilirubin break down to urobilin then stercobilin
- Gallbladder = a muscular pouch that stores bile and expels bile when needed via the cystic duct and the bile duct.
Large Intestine: Gross Anatomy
- Ileocecal valve to anus (~1.5 m)
- Haustra: Pocket-like segments of large intestine
- Epiploic appendages: Fat filled pouches of visceral peritoneum
- Cecum: Blind pouch (below ileocecal valve)
- Appendix: Attached to cecum (lymphoid)
- Colon: Ascending, transverse, descending, sigmoid
- Transverse colon and sigmoid colon are intraperitoneal; anchored by mesentery. The rest of the colon is retroperitoneal
- Rectum
- Anal canal.
Large Intestine: Microscopic Anatomy
- All 4 layers present
- Mucosa: Simple columnar epithelium until anal canal (stratified squamous)
- No folds or villi. No significant enzyme secretions
- Crypts: Invaginations of mucosa contain large numbers of goblet cells that secrete mucous for protection and lubrication
- Bacterial flora
- Ferment indigestible CHO: Produces about 500 mL of gas per day
- Synthesize B complex vitamins and most vitamin K
- Propulsion:
- Haustra contractions: Stretch stimulate haustra to contract moving (and mixing) contents to next haustra
- Mass peristalsis: Long, slow contractile waves moving contents toward rectum (3–4 per day)
- Gastrocolic reflex: Food intake causes mass peristalsis.
URINARY SYSTEM
Urinary System Components
- Kidneys
- Ureters
- Urinary bladder
- Urethra
- Kidneys
- 1% body weight
- Retroperitoneal, posterior abdominal wall
- Adrenal gland anchored superior.
Three Layers CT Anchor Kidneys
- Renal capsule: Collagen fibers covering organ.
- Adipose capsule: Adipose cushion around renal capsule.
- Renal fascia: Collagen fibers fused to renal capsule and deep fascia of body wall and peritoneum.
Renal ptosis = floating kidney: Starvation or injury, kidney loose from body wall, could twist blood vessels or ureters
- Hilum: Where renal arteries, renal, veins, ureters enter/exit
- Hilum opens to renal sinus
- Renal sinus lined with renal apsule, contiguous with outside.
Kidney Has Two Layers
- Cortex: Superficial, contact renal capsule, houses filtration structures (nephrons)
- Medulla: 6–18 renal pyramids, parallel bundles of collection tubules, apex, papilla, points toward renal sinus
- Kidney divided into sections: renal lobes
- Renal lobe = renal pyramid + surrounding cortex called renal columns, lobe is complete site of urine production.
Blood Supply and Innervation to Kidney
- Receives 20–25% cardiac output
- Highly vascularized, many capillaries involved in filtration (nephrons)
- Innervation from renal plexus controlled by ANS
- Most is sympathetic to:
- Adjust rate of urine formation (change BP and flow at nephron)
- Stimulate release of renin (restricts water and Na+ loss at nephron).
Nephron
- Smallest functional unit of kidney
- More than 1 million per kidney
- Two major parts:
- Renal corpuscle = glomerular capsule + glomerulus
- Renal tubule = proximal convoluted tubule (PCT) + nephron loop + distal convoluted tubule (DCT).
Two important capillary beds associated with each nephron:
- Glomerulus: Filtration
- Peritubular capillaries: Reclaim filtrate, concentrate urine
Both connected to arterioles only (not for O2 exchange) afferent arteriole capillary efferent arteriole.
Two Types of Nephrons
- Cortical nephrons: Majority, in cortex, short nephron loops
- Juxtamedullary nephrons: 15%, at cortex/medulla interface, long nephron loops, important for water conservation and concentrated urine.
Renal Corpuscle: Site of Filtration
Two parts:
- Glomerular capsule: Thin parietal epithelium, forms capsule around glomerulus
- Glomerulus: Fenestrated capillaries covered by podocytes = visceral epithelium, intertwine to create filtration slits on surface of capillaries, slits smaller than fenestrations in glomerular capillaries to restrict filtration of large molecules.
Renal Tubule
Reabsorption to process raw filtrate into urine—Three parts:
- PCT: Simple cuboidal epithelium with microvilli, reabsorbs organic nutrients, ions, water, and small plasma proteins from filtrate exiting glomerular capsule.
- DCT: Simple cuboidal epithelium, flat surface, has four important functions:
- Secretion: Removal of wastes from peritubular capillaries into filtrate
- Reabsorb Na+ and Ca2+ from filtrate
- Optional H2O reabsorption from filtrate under hormonal control
- Contribute to formation of juxtaglomerular apparatus.
Juxtaglomerular Apparatus (JGA)
Consists of two cell types:
- Endocrine cells of DCT = macula densa
- Granular cells of afferent arteriole = juxtaglomerular cellsTogether cells monitor blood and produce:
- Renin: Enzyme, restricts Na+ and H2O at nephron
- Erythropoietin: Hormone, stimulates RBC production.
Collecting System
Collecting ducts + papillary ducts nephrons
1 collecting duct (renal pyramid) many collecting ducts 1 papillary duct
- Final osmotic concentration of filtrate adjusted by collecting duct, after this urine is complete and exits kidney:
- Papillary duct (renal papilla) minor calyx major calyx renal pelvis ureter
Polycystic kidney disease = genetic, cysts form that cause swelling of kidney tubules, compression reduces function.
Urine Transport, Storage and Elimination
- Urine production and modification: Renal tubules and collecting system
- Once in renal pelvis, urine complete, excreted
via ureters, bladder, urethra.
Nephrolithiasis = blockage of urinary passage, e.g. calculi (kidney stone); crystalized deposits of calcium, magnesium, or uric acid, form in renal pelvis, can become lodged in ureters. Large ones may need disruption by a lithotripter.
Ureters
Connect renal pelvis to urinary bladder wall layers:
- Mucosa with transitional epithelium
- Muscularis with two layers of smooth muscle
- Adventitia, attaches to posterior body wall
- Contractions occur every 30 sec to force urine toward bladder.
Urinary Bladder
- Wall folded into rugae when empty (expands)
- Wall layers:
- Mucosa with transitional epithelium
- Muscularis with 3 layers of smooth muscle = detrusor muscle (contraction causes expulsion of urine from bladder)
- Detrusor muscle thickened around urethral opening to create the internal urethral sphincter (provides involuntary control over release of urine)
- Adventitia, fibrous, anchors bladder to pelvic floor.
Urethra
- Single tube, connects bladder to environment
- Lined with pseudostratified columnar epithelium
- Passes through band of skeletal muscle that forms external urethral sphincter, under voluntary control, relaxation results in micturition.
Micturition Reflex
- When bladder contains ~200 mL urine, stretch receptors triggered, signal conscious awareness of pressure and stimulates contraction of detrusor muscle
- Voluntary maintenance of contracted external urethral sphincter prevents urination, detrusor will relax (opening will open internal urethral sphincter allowing urination)
- Continued increase in urinary volume will repeatedly trigger reflex
- If volume exceeds ~500 mL, forced relaxation of internal and external urethral sphincters will result in non-voluntary urination/micturition Incontinence = inability to voluntarily control urine excretion, due to: loss of muscle tone, damage to sphincters, damage to nerves or control centers in brain.
Age-related Changes
- Decline in functional nephrons
- Reduction in GFR (damage or blood flow)
- Reduced sensitivity to ADH = dilute urine
- Problems with micturition
- Incontinence
- Urinary retention (enlarged prostate).
CRANIAL NERVES AND THEIR FUNCTIONS
The cranial nerves are the 12 pairs of nerves that leave the brain via their own individual apertures in the skull.
List of the Cranial Nerves
- CN I: Olfactory (smell)
- CN II: Optic (sight)
- CN III: Oculomotor (moves eyelid and eyeball and adjusts the pupil and lens of the eye)
- CN IV: Trochlear (moves eyeballs)
- CN V: Trigeminal (facial muscles incl. chewing; facial sensations)
- CN VI: Abducens (moves eyeballs)
- CN VII: Facial (taste, tears, saliva, facial expressions)
- CN VIII: Vestibulocochlear (auditory)
- CN IX: Glossopharyngeal (swallowing, saliva, taste)
- CN X: Vagus (Control of PNS e.g. smooth muscles of GI tract)
- CN XI: Accessory (moving head and shoulders, swallowing)
- CN XII: Hypoglossal (tongue muscles-speech and swallowing).
More information about the names, numbers and functions of the 12 cranial nerves is summarized in the following table.18
S. No. | Cranial nerve (number and name) | Function(s) of cranial nerve | ||
|---|---|---|---|---|
1 | CN I: Olfactory (sensory) | Smell | ||
2 | CN II: Optic (sensory) | Vision, also called eyesight. (Each optic nerve contains approx a million nerve fibers that receive information from the rod and cone cells of the retina.) | ||
3 | CN III: Oculomotor (mixed, mainly motor) | Moves the eyeball and eyelid, adjusts the lens of the eye for near vision and also constricts the pupil of the eye via motor fibers distributed to muscles located in and around the eye. | ||
Parasympathetic fibers adjust the size of the pupil and the shape of the lens of the eye. | Fibers outside the eye extend to the upper eyelid and the extrinsic muscles that turn the eyeball in different directions, (incl. the superior rectus, medial rectus, inferior rectus and inferior oblique muscles). | |||
4 | CN IV: Trochlear (mixed, mainly motor) | Moves the eyeballs by sending nerve impulses to the superior oblique muscles which are among the group of muscles that rotate the eyeballs in their sockets. (The action of this nerve is coordinated with those of the oculomotor and abducens nerves, i.e. cranial nerves III and VI.) | ||
5 | CN V: Trigeminal (mixed) | This is largest cranial nerve and splits into the following three divisions, each of which includes both motor and sensory fibers.
The motor fibers of all 3 divisions control the facial muscles involved in chewing. The sensory fibers convey sensations of touch, pain and temperature from the front of the head including the mouth and also from the meninges. | ||
6 | CN VI: Abducens (mixed, mainly motor) | Moves the eyeballs outwards by sending nerve impulses to the lateral rectus muscles. | ||
7 | CN VII: Facial (mixed) | Sensory fibers are concerned with taste via the taste buds at the front of the tongue. Motor fibers control secretion of tears via the lacrimal glands and saliva via the sublingual salivary glands as well as facial expressions via some of the muscles of facial expression. A branch of the facial nerve regulates the tension on the ear ossicles. | ||
8 | CN VIII: Vestibulocochlear (mixed, mainly sensory) | Two branches: Vestibular nerve (senses equilibrium) and Cochlear nerve (hearing) | ||
Vestibular nerve: Aids equilibrium by carrying impulses from the semicircular canals—providing info about posture, movement and balance | Cochlear nerve: Carries impulses from the cochlea, so is known as the nerve of hearing | |||
9 | CN IX: Glossopharyngeal (mixed) | Motor fibers
| ||
Sensory fibers
| ||||
10 | CN X: Vagus (mixed) | Motor fibers:
| ||
Sensory fibers: | ||||
11 | CN XI: Accessory (mixed, mainly motor) | Arises from two roots, cranial and spinal. | ||
Cranial parts: Controls swallowing movements because nerve fibers (from the cranial root of cranial nerve XI) join the vagus nerve to form the recurrent laryngeal nerve which supplies the internal laryngeal muscles. | Spinal Parts: Governs movement of the head and shoulders by supplying the sternocleidomastoid and trapezius muscles in the (anterior and posterior) regions of the neck. | |||
12 | CN XII: Hypoglossal (mixed, mainly motor) | Supplies the muscles of the tongue—responsible for the tongue movements involved in speech and swallowing | ||
LIST OF HUMAN HORMONES AND THEIR IMPORTANCE
Hormones; we blame them for an awful lot. When a teenager acts out, ‘you know how those hormones are!’ When a pregnant woman starts crying at a hot dog commercial, we claim, ‘Do not mind her, it is all those hormones.’ But how many people actually know what the hormones are that they are referring to? Blaming hormones for all of life's problems has just become a habit instead of something that is really well known.
Some hormones you may have heard of and same may sound like gibberish. The functions of some are relatively easy to understand, while others require a science major. We have assembled a list of some of the more commonly known hormones that are responsible for some of the most major functions of the body. It is about time we got to know the 20hormones that we place the blame on, and know which one is to blame for what, so that next time your moody teenager talks back, you'll know the serotonin is to blame.
- Melatonin: Think of melatonin as your biological clock. This hormone is responsible for the way you feel throughout the day as far as alertness is concerned. All those drowsy feelings? Blame the melatonin.
- Serotonin: This is the one you can blame for PMS and your moody teenager. Serotonin controls your mood, appetite, and your sleep cycles.
- Thyroxin: A form of thyroid hormone, thyroxin increases the rate of your metabolism and also affects protein synthesis, which is the process that cells go through to build protein.
- Epinephrine: This is one that you have most likely heard of; it is also called adrenaline. Among a whole list of other things, epinephrine is responsible for what is known as the, ‘fight or flight’ response. This is the hormone that tells you when to fight and when it is best to run. Some of the bodily responses demonstrated when this hormone kicks in are dilated pupils, increased heart rate, and tensing of the muscles.
- Norepinephrine: Also called noradrenaline, this hormone controls the heart and blood pressure. Norepinephrine also contributes to the control of sleep, arousal, and emotions. Obvious effects take place when there is too much or too little of this hormone. Too much gives you an anxious feeling while too little can leave you feeling depressed or sedated.
- Dopamine: This controls the heart rate and also assists in perception; deciphering what is real and what is not.
- Antimullerian hormone: An inhibitor for the release of prolactin, the protein responsible mainly for lactation.
- Adrenocorticotropic hormone: This assists in synthesizing corticosteroids, which are responsible for stress response, blood electrolyte levels, and other physiologic systems.
- Angiotensinogen: Responsible for the narrowing of blood vessels; a process known as vasoconstriction.
- Antidiuretic hormone: This hormone is also known by other names, but it is mainly responsible for retaining water within the kidneys.
- Atrial natriuretic peptide: A peptide hormone secreted by the cells of the heart and other muscles. It is mostly involved with the control of water, sodium, potassium, and fat within the body.
- Calcitonin: Aids in constructing bone and reducing blood calcium.
- Cholecystokinin: Aids in the release of digestive enzymes for the pancreas and acts as an appetite suppressant.
- Corticotropin-releasing hormone: Releases cortisol in response to stress.
- Erythropoietin: Stimulates the production of erythrocytes, which are blood cells responsible for delivering oxygen.
- Follicle-stimulating hormone: Stimulates the follicles within the sex organs of both males and females.
- Gastrin: Secretes gastric acid.
- Ghrelin: Hunger stimulant as well as aiding in the secretion of the growth hormone.
- Glucagon: Helps to increase the blood glucose level.
- Growth hormone-releasing hormone: As its name clearly implies, this hormone releases the growth hormone.
- Human chorionic gonadotropin: Keeps the immune system from attacking a forming embryo during pregnancy.
- Growth hormone: Helps to stimulate growth and the reproduction of cells.
- Insulin: Responsible for several anabolic effects, primarily glucose intake.
- Insulin-like growth factor: Has the same effects as insulin while also regulating the growth and development of cells.
- Leptin: Slows down the appetite while simultaneously speeding up metabolism.
- Luteinizing hormone: Aids ovulation in women and testosterone production in men.
- Melanocyte stimulating hormone: Produce melanocytes, which are responsible for the pigment in skin and hair.
- Orexin: Increases the appetite while also increasing your alertness and energy levels.
- Oxytocin: A hormone that plays a major role in reproduction, it aids in orgasm and is also responsible for the release of breast milk.
- Parathyroid hormone: Among other functions, this hormone is mainly responsible for the activation of Vitamin D.
- Prolactin: A major contributor in sexual satisfaction and the production of breast milk.
- Secretin: Inhibits gastric acid production.
- Aldosterone: Mainly responsible for absorbing sodium in the kidneys to increase the volume of blood within the body.
- Testosterone: The major male hormone, testosterone is responsible for sex drive, development of the sex organs, and the changes that take place during puberty.
- Androstenedione: Essentially estrogen.
- Estradiol: In males, this hormone is responsible for preventing what is basically known as cell death of the germ cells. In females, this hormone is in overdrive. Among other things, estradiol accelerates height and metabolism, maintains the blood vessels and skin, aids in water retention, and even aids in hormone-sensitive cancers.
- Progesterone: A major contributor to the body's support of pregnancy.
- Lipotropin: Stimulates the production of pigment by aiding in melanin production.
- Brain natriuretic peptide: Aids in reducing blood pressure.
- Histamine: A hormone based in the stomach, histamine aids in the secreting of gastric acid.
- Endothelin: Controls muscle contractions within the stomach.
- Enkephalin: Simply a pain regulator.
These are only examples of some of the hormones within the body; there are more complex hormones whose functions are not easily understood. Our bodies (when in proper working order) function like well-oiled machines, and the hormones are a major part of nearly every process. Clearly, hormones are responsible for much more than angry teens, squeaky voices, and weepy pregnant women.
MULTIPLE CHOICE QUESTIONS
- The endocrine part of pancreas consist of:
- Islet of Langerhans
- Tubular acne
- Columnar cells
- Transitional cells
- Cirrhosis of liver means:
- Necrosis of liver cells
- Inflammation of liver cells
- Fibrosis of liver cells
- Edema of liver cells
- 80% of blood supply to liver is by:
- Hepatic artery
- Hepatic vein
- Splenic artery
- Portal vein
- Artery supplying visual area of brain is:
- Posterior cerebral
- Middle cerebral
- Anterior cerebral
- Interior carotid
- All the statements are true about coronary arteries EXCEPT:
- Are functionally end arteries
- Get filled during systole
- Are enlarged Vasa vosa
- Are most prone of any arteries to develop atherosclerosis
- Paired skull bone are:
- Frontal, parietal
- Occipital, temporal
- Parietal, temporal
- Sphenoid, ethmoid
- Fracture of floor of anterior cranial fossa may cause:
- Discharge of CSF through nose
- Black eyes
- Bleeding through nose
- All of the above
- The internal supporting framework of cell is:
- Cytoskeleton
- Ribosome
- Plasma membrane
- Microfilament
- Total number of true ribs in human body are:
- 10
- 20
- 12
- 24
- The strongest muscle in human body is:
- Porns major
- Masseter
- Quadratus femoris
- Biceps brachii
- Following are the connective tissue EXCEPT:
- Cartilage
- Blood
- Myocardium
- White fibrous tissue
- The only bone in human body that does not articulate with any other bone:
- Patella
- Coccyx
- Hyoid
- Stapes
- Total pair of spinal nerves are:
- 28
- 30
- 31
- 32
- Central nervous system consist of:
- Brain, spinal cord and afferent nerves
- Brain and spinal cord
- Brain, spinal cord and efferent nerves
- Cerebrum, cerebellum and medulla
- Bone containing large air spaces lined by epithelium is:
- Long bone
- Irregular bone
- Pneumatic bones
- Sesamoid bones
- Elastic cartilage is present in:
- Trachea
- Bronchus
- Epiglottis
- Intervertebral disc
- Nerve supply of biceps brachial muscle is:
- Musculocutaneous nerve
- Radial nerve
- Ulnar nerve
- Median nerve
- Artey used for measuring of blood pressure is:
- Brachial artery
- Radial artery
- Ulnar nerve
- Median nerve
- Extension of knee joint is brought about by:
- Quadriceps femoris
- Hamstring
- Gluteus maximus
- Popliteus
- Foot drop is due to injury to:
- Femoral nerve
- Obturator nerve
- Deep peroneal nerve
- Tibial nerve
- Right lung contains:
- Eight bronchopulmonary segments
- Nine bronchopulmonary segments
- Ten bronchopulmonary segments
- None of the above
- Sternal puncture is done through:
- Upper part of sternal body
- Lower half of manubrium
- Upper half of manubrium
- None of the above
- Bile duct opens into the following part of duodenum:
- Superior
- Descending
- Horizontal
- Ascending
- Right testicular vein open into:
- Inferior vena cava
- Right renal vein
- Left renal vein
- None of the above
- Following are the muscle of mastication EXCEPT:
- Massester
- Temporalis
- Buccinator
- Lateral and medial pterygoid
- Following air sinuses open into the middle meatus of the nose EXCEPT:
- Frontal
- Maxillary
- Anterior ethmoidal
- Posterior ethmoidal
- Occipital lobe of cerebrum contains:
- Somatomotor area
- Somatosensory area
- Visual area
- Auditory area
- Usually lumbar puncture is done by inserting LP needle between:
- 12th thoracic and 1st lumbar vertebra
- 1st and 2nd lumbar vertebra
- 3rd and 4th lumbar vertebra
- 1st and 2nd sacral vertebra
- Superior radio lunar joint is a _____ joint.
- Ball and socket
- Pivot
- Condylar joint
- Fibrous
- Injury to the radial nerve in arm causes:
- Claw hand
- Erbs paralysis
- Wrist drop
- Apr thumb deformity
- Anterior part of interventricular septum is supplied by the branch of ____________ artery.
- Right coronary
- Left coronary
- Circumflex
- Right marginal
- Inferior vena caval opening in the diaphragm is at the level of ________ vertebra.
- T8
- T9
- T10
- T11
- Most dangerous position of appendix is ___.
- Pelvic
- Splenic
- Paracolic
- Promontoric
- Deep inguinal ring is an apparent opening in:
- Fascia transversalis
- Peritoneum
- Internal oblique
- External oblique
- Injury to the common peroneal nerve at the level of neck devils will cause:
- Foot drop
- Inability to evert foot
- Sensory loss over anterior and lateral aspect of leg and foot
- All the above
- All are true about sesamoid bone except:
- Developed after birth
- Develop in tendons
- Periosteum is present
- After the pull of muscle
- Intramuscular injection in the gluteal regions are given in the________ quadrant.
- Superio medial
- Superio lateral
- Inferio medial
- Inferio lateral
- Hairpin bend are associated with _________ artery.
- Nutrient
- Periosteal
- Epiphyseal
- Metaphyseal
- Blood supply to superio lateral surface of cerebral hemisphere is largely given by _________ artery.
- Anterior cerebral
- Middle cerebral
- Posterior cerebral
- Anterior choroidal
- Age of closure of anterior fontanelle is:
- One month
- Six months
- One year
- One and half year
- Taste of sensation from anterior 2/3 of the tongue is carried by __________ nerve.
- Glossopharyngeal
- Hypoglossal
- Chorda tympani
- Vagus
- Axillary artery is continuation of:
- Brachiocephalic artery
- Subclevian artery
- Common carotid artery
- Aorta
- The safe site for giving intranet muscular injection in gluteal region is:
- Upper and inner quadrant
- Lower and inner quadrant
- Upper and outer quadrant
- Lower and outer quadrant
- Metacarpal bones are examples of:
- Short bones
- Irregular bones
- Miniature bone
- Supernumerary bone
- The cells lacking nucleus are:
- Mast cells
- Erythrocytes
- Neurons
- Muscle cells
- The member of hematopoietic-lymphoid system is:
- Spleen
- Adrenal medulla
- Kidney
- Pancreas
- The part of male reproductive system, ligated in family planning operation is:
- Testis
- Prostate
- Vas deferens
- Epididymis
- Bile is synthesized in:
- Gallbladder
- Liver
- Bile duct
- Duodenum
- The vein carrying oxygenated blood is:
- Portal vein
- Renal vein
- Great cerebral vein
- Pulmonary vein
- The taste sensation from posterior 1/3rd of tongue are carried by:
- Hypoglossal nerve
- Facial nerve
- Vagus nerve
- Glossopharyngeal nerve
- A muscle of leg which is called peripheral heart:
- Poplitial
- Soleus
- Tibialis posterior
- Gastrocnemius
- The safety muscle of the tongue is:
- Genioglossus
- Hyoglossus
- Styloglossus
- Palatoglossus
- The part of lung where exchange of gases takes place is:
- Bronchus
- Alveoli
- Bronchioles
- Stromal
- The insuline is secreted by:
- Pituitary gland
- Pancreas
- Liver
- Stomach
- The fovea on the head of femur gives attachment to:
- Gluteus medius
- Iliofemoral ligament
- Round ligament
- Pubofemoral ligament
- An example of compound synovial joint is:
- Shoulder joint
- Knee joint
- Hip joint
- Interphalangeal joint
- All are unpaired cartilages of larynx EXCEPT:
- Thyroid
- Cricoid
- Epiglottis
- Arytenoid
- Cerebrospinal fluid is formed by:
- Arachnoid villi
- Arachnoid granulation
- Choroid plexus
- Cisterna magna
- Cervical vertebrae adequate recognised by the presence of:
- Foramen transversarium
- Foramen ovals
- Foramen magnum
- Vertebral foramen
- All are the branches of facial artery EXCEPT:
- Submental
- Superior labial
- Transverse facials
- Lateral nasal
- The receptors for hearing are located in:
- Utricle
- Saccule
- Ampulla of semicircular canals
- Spiral organ of Corti
- The only long bone lying horizontally is:
- Rib
- Clavicle
- Pelvis
- Radius
- The inner visual layer of serous pericardium is called:
- Endocardium
- Epicardium
- Myocardium
- Mediastinum
- The muscle of the back of the thigh is called:
- Gluteal muscle
- Popliteal muscle
- Hamstring muscle
- Quadriceps muscle
- The total genetic information in a cell is carried by its:
- Mitochondria
- Ribosome
- Chromosome
- Golgi complex
- The arterial supply to retina is by:
- Cilliary artery
- Central artery
- Opthlamic artey
- Fascial artery
- The content of femoral canal is:
- Femoral artery
- Femoral nerve
- Femoral vein
- Femoral lymph node
- All are intracapsular structure of knee joint except:
- Cruciate ligament
- Coronary ligament
- Meniscofemoral ligament
- Tibial collateral ligament
- Wrist drop is a result of injury to _______nerve.
- Median nerve
- Radial nerve
- Ulnar nerve
- Musculocutaneous nerve
- Lymphatic from the testis drain into:
- Internal iliac node
- Superficial inguinal node
- External iliac node
- Para-aortic node
- All are site of portacaval anastomosis EXCEPT:
- Lower end of esophagus
- Ileocecal junction
- Posterior abdominal wall
- Base area of liver
- Right border of the heart is formed by:
- Right atrium
- Right ventricle
- Right atrium and right ventricle
- Superior vena cava
- Sensory supply to face is predominantly by branches of:
- Oculomotor nerve
- Facial nerve
- Trigeminal nerve
- Accessory nerve
- Tongue is supplied by all EXCEPT:
- Lingual
- Cords tympani
- Glossopharyngeal
- Hypoglossal
- Retraction of the protruded mandible is done by:
- Medial pterygoid
- Lateral pterygoid
- Masseter
- Temporalis
- Facial artery is a branch of:
- Common carotid artery
- Internal carotid artery
- External carotid artery
- Subclavian artery
- The life span of an RBC is:
- 100 days
- 120 days
- 180 days
- 80 days
- Hypothyroidism in infants leads to:
- Addison's disease
- Myxedema
- Cretinism
- Thyrotoxicosis
- The bond of protein structure that is not broken in denaturation is:
- Hydrogen
- Peptide
- Ionic
- Disulfide
- Sphingomyelins are:
- Essential fatty acids
- Simple lipids
- Compound lipids
- Derived lipids
- Hormone secretion increase:
- Gastric secretion
- Salivary secretion
- Pancreatic secretion
- Intestinal secretion
- Control of motor movement and coordination is due to:
- Vestibular organ
- Cerebellum
- Limbic system
- Hypothalamus
- Correction of hypermetropia is done by prescribing:
- Concave lenses
- Cylindrical lenses
- Convex lenses
- Planoconcave lenses
- Approximate tidal volume is:
- 150 mL
- 750 mL
- 500 mL
- 1000 mL
- Diabetes mellitus is caused by:
- Less secretion of insulin
- Excess of glucose intake
- Excess of insulin
- Excess of protein intake
- Functional unit of kidney:
- Sinusoid
- Pelvis
- Glomerulus
- Calyces
- Normal serum bilirubin concentration is:
- 0.2 to 1.0 mg%
- 2.0 to 3.0 mg%
- 1.0 to 2.0 mg %
- None of the above
- Decrease in platelet count is known as:
- Leucopenia
- Polycythemia
- Anemia
- Thrombocytopenia
- Which vitamin is required for clotting mechanism?
- Vitamin K
- Vitamin A
- Vitamin B
- Intrinsic factors
- Decrease in WBC county is known as:
- Leukemia
- Leukocytosis
- Leucopenia
- All the above
- 4 kcal of energy is liberated after oxidation EXCEPT for:
- Carbohydrates
- Fats
- Protein
- Glycogen
- Following are the pneumatic bones EXCEPT:
- Maxilla
- Mandible
- Frontal
- Sphenoid
- Following vein open into right atrium EXCEPT:
- Superior vena cava (SVC)
- Coronary sinus
- Inferior vena cava (IVC)
- Great cardiac vein
- Fertilization of ovum occur in the ___ of fallopian tube.
- Infundibulum
- Ampulla
- Isthmus
- Intramural part
- Hypoglossal nerve supplies all the following muscle EXCEPT:
- Genioglossus
- Hypoglossus
- Palatoglossus
- Styloglossus
- Medial plane divides body into:
- Anterior and posterior plane
- Right and left equally
- Superior and inferior halves
- Also called transverse plane
- Mental foramen is an opening in:
- Frontal bone
- Maxilla
- Zygomatic
- Mandible
- Deltoid muscle:
- Insert on deltoid tuberosity of humerus
- Initiate abduction
- Innervated by musculocutaneous nerve
- Forms border of qudrangular space
- The femoral canal:
- The medial most compartment of femoral sheet
- Contains femoral canal
- Is wider in male than female
- Has inferior epigastric vessel
- Medial longitudinal arch of foot is formed by all EXCEPT:
- Calcaneus
- Cuboid
- Talus
- Navicular
- Head of pancreas is closely related to:
- Second part of duodenum
- Left lobe of liver
- Spleen
- Ascending colon
- One of the following is not a carpel bone:
- Capitate
- Cuboid
- Lunate
- Hamate
- Foramen magnum is opening in:
- Parietal bone
- Sphenoid bone
- Occipital bone
- Temporal bone
- Content of carotid sheet are all EXCEPT:
- Internal jugular vein
- Common carotid artery
- Sympathetic trunk
- Vagus nerve
- Portal vein is formed by union of:
- Superior mesentric and splenic vein
- Splenic vein and inferior vena cava
- Superior mesentric and inferior venal cava
- Infertvena cava n hepatic vein
- Vertebra is _________ type of bone.
- Short
- Flat
- Sesamoid
- Irregular
- The muscle that unlocks the knee joint is:
- Popliteus
- Gastrocnemius
- Quadriceps femoris
- Plantaris
- Coronary arteries are the branches of:
- Ascending aorta
- Left pulmonary artery
- Right pulmonary artery
- Brachiocephalic trunk
- Transitional epithelium lines the following organ:
- Skin
- Jejunum
- Second part of duodenum
- Urinary bladder
- Auditory tube opens into:
- Nasopharynx
- Nasal cavity
- Oral cavity
- Larynx
- Deltoid muscle is supplied by:
- Musculocutaneous nerve
- Axillary nerve
- Radial nerve
- Supracapsular nerve
- Covering of the bone is called:
- Perichondrium
- Periosteum
- Endosteum
- Endocardium
- Nerve supply of biceps brachii is:
- Radial
- Median
- Musculocutaneous
- Axillary
- Winging of scapula is due to paralysis of:
- Serratus anterior
- Latissimus dorsi
- Pectoralis major
- Deltoid
- Nerve supply of gluteus maximus:
- Superior gluteal
- Inferior gluteal
- Femoral
- Obturator
- Floating rib is:
- 7th
- 8th
- 9th
- 12th
- Left lung consist of:
- 2 lobes
- 3 lobes
- 4 lobes
- 5 lobes
- Apex of the heart is formed by:
- Right atrium
- Left atrium
- Right ventricle
- Left ventricle
- Humerus is which type of bone:
- Long
- Irregular
- Short
- Sesamoid
- Nerve related to surgical neck of humerus is:
- Radial
- Musculocutaneous
- Median
- Axillary
- Lining epithelium of the skin is:
- Startified squamous epithelium
- Simple squamous epithelium
- Transitional epithelium
- Simple cuboidal epithelium
- Following is an example of elastic cartilage:
- Pinna of the ear
- Intervertebral disc
- Menisci of knee joint
- Articular disc of temporomandibular joint
- Following are the features of interior of right atrium EXCEPT:
- Sulcus terminalis
- Fossa ovalis
- Opening of coronary sinus
- Moderator band
- Scapula is a ________ type of bone.
- Sesamoid
- Flat
- Irregular
- Long
- One of the following artery is used for measuring BP:
- Ulnar
- Axillary
- Subclavian
- Brachial
- Hip joint is following type of joint:
- Condylar
- Ball and socket
- Plane
- Saddle
- Following opening are present in the right atrium EXCEPT:
- Superior vena cava (SVC)
- Inferior vena cava (IVC)
- Coronary sinus
- Pulmonary trunk
- Ulnar nerve is a branch of:
- Medial cord of brachial plexus
- Lateral cord of brachial plexus
- Posterior cord of brachial plexus
- Lower trunk of brachial plexus
- How many lumbar vertebrae are present in vertebral column?
- 5
- 7
- 10
- 12
- The serious membrane lining the thoracic cavity is called:
- Pericardium
- Pleura
- Synovial membrane
- Peritoneum
- Which of the following is a part of large intestine?
- Jejunum
- Ileum
- Duodenum
- Cecum
- Pulmonary vein open into which chamber of heart:
- Left atrium
- Left ventricle
- Right atrium
- Right ventricle
- Movement towards midline of the body is called as:
- Flexion
- Abduction
- Extension
- Addiction
- Which cavity is present within the cerebral hemispheres?
- Third ventricle
- Fourth ventricle
- Lateral ventricle
- Cerebral aqueduct
- Which of the following is a long bone?
- Vertebrae
- Metacarpals
- Tibia
- Frontal
- The central tendon of respiratory diaphragm is associated with heart:
- Inferiorly
- Anteriorly
- Posteriorly
- Laterally
- Which of the following is not a part of brainstem:
- Midbrain
- Pond
- Medulla oblongata
- Cerebellum
- The length of adult esophagus (in cm) is about:
- 25
- 26
- 27
- 29
- Posterior boundary of cranial cavity is formed by which bone?
- Temporal
- Occipital
- Frontal
- Parietal
- Spinal cord extends from foramen magnum to lower border of vertebra:
- T11
- T12
- L1
- L3
- All are the layers of scalp EXCEPT:
- Skin and convective tissue
- Endosteal layer of dura mater
- Aponeurosis
- Loose areolar tissue
- Superior radio-ulnar joint is ________ variety of joint.
- Ball and socket
- Condylar
- Pivot
- Fibrous
- All the following veins drain into coronary sinus EXCEPT:
- Great cardiac vein
- Small cardiac vein
- Middle cardiac vein
- Anterior cardiac vein
- Left Suprarenal vein drains into:
- Inferior vena cava
- Left testicular vein.
- Left renal vein
- Splenic vein
- All the muscles are abductors of eyeball EXCEPT:
- Medial rectus
- Superior rectus
- Inferior oblique
- Inferior rectus
- Septomarginal band is found in:
- Right atrium
- Right ventricle
- Left atrium
- Left ventricle
- Stomach bed includes all EXCEPT:
- Spleen
- Pancreas
- Splenic artery
- Right kidney
- All of the following are projection fibers EXCEPT:
- Corona radiata
- Pyramidal tract
- External capsule
- Internal capsule
- Following is the fixed part of urinary bladder:
- Base
- Apex
- Neck
- None of the above
- Thyroid gland produces:
- T3
- T4
- Calcitonin
- All the above
- All of the following are nuclei of cerebellum EXCEPT:
- Dentate
- Emboliform
- Olivary
- Fastigial
- Pisiform is an example of:
- Short bone
- Irregular bone
- Sesamoid bone
- Flat bone
- Apex beat of heart is felt in:
- 3rd Intercostal space
- 4th Intercostal space
- 5th Intercostal space
- 6th Intercostal space
- Hilum of the right lung show:
- Two bronchus
- One bronchial
- One vein
- Two arteries
| ANSWERS |
1. | (a) | 21. | (c) | 41. | (c) | 61. | (c) | 81. | (c) | 101. | (a) | 121. | (a) | 141. | (b) |
2. | (c) | 22. | (a) | 42. | (a) | 62. | (d) | 82. | (b) | 102. | (b) | 122. | (d) | 142. | (c) |
3. | (d) | 23. | (b) | 43. | (c) | 63. | (b) | 83. | (a) | 103. | (a) | 123. | (a) | 143. | (b) |
4. | (d) | 24. | (a) | 44. | (a) | 64. | (b) | 84. | (c) | 104. | (b) | 124. | (a) | 144. | (c) |
5. | (d) | 25. | (c) | 45. | (b) | 65. | (c) | 85. | (c) | 105. | (c) | 125. | (a) | 145. | (d) |
6. | (c) | 26. | (c) | 46. | (a) | 66. | (c) | 86. | (a) | 106. | (c) | 126. | (b) | 146. | (a) |
7. | (a) | 27. | (c) | 47. | (c) | 67. | (c) | 87. | (c) | 107. | (c) | 127. | (d) | 147. | (a) |
8. | (a) | 28. | (c) | 48. | (b) | 68. | (d) | 88. | (a) | 108. | (d) | 128. | (b) | 148. | (b) |
9. | (d) | 29. | (b) | 49. | (d) | 69. | (d) | 89. | (c) | 109. | (a) | 129. | (d) | 149. | (d) |
10. | (b) | 30. | (c) | 50. | (d) | 70. | (b) | 90. | (d) | 110. | (a) | 130. | (a) | 150. | (c) |
11. | (c) | 31. | (b) | 51. | (c) | 71. | (d) | 91. | (a) | 111. | (d) | 131. | (d) | 151. | (c) |
12. | (c) | 32. | (a) | 52. | (a) | 72. | (b) | 92. | (c) | 112. | (a) | 132. | (b) | 152. | (d) |
13. | (c) | 33. | (b) | 53. | (b) | 73. | (c) | 93. | (b) | 113. | (b) | 133. | (d) | 153. | (c) |
14. | (b) | 34. | (a) | 54. | (b) | 74. | (c) | 94. | (b) | 114. | (b) | 134. | (a) | 154. | (c) |
15. | (c) | 35. | (a) | 55. | (c) | 75. | (a) | 95. | (b) | 115. | (c) | 135. | (d) | 155. | (c) |
16. | (c) | 36. | (c) | 56. | (b) | 76. | (c) | 96. | (b) | 116. | (a) | 136. | (b) | 156. | (c) |
17. | (a) | 37. | (b) | 57. | (d) | 77. | (c) | 97. | (b) | 117. | (b) | 137. | (c) | ||
18. | (a) | 38. | (b) | 58. | (c) | 78. | (b) | 98. | (b) | 118. | (d) | 138. | (a) | ||
19. | (a) | 39. | (a) | 59. | (b) | 79. | (a) | 99. | (d) | 119. | (a) | 139. | (d) | ||
20. | (b) | 40. | (d) | 60. | (a) | 80. | (b) | 100. | (d) | 120. | (d) | 140. | (a) |