Preliminary Pages

1Anatomy and Physiology for General Nursing

2Anatomy and Physiology for General Nursing

SM Raju BSc, MBBS, MD (Biochemistry) Professor and Head Department of Biochemistry Sri Siddartha Medical College, Tumkur Bindu Madala MD Associate Professor Texas A&M University Department of Medicine Scott and White Clinic

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Jitendar P Vij

Jaypee Brothers Medical Publishers (P) Ltd

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Anatomy and Physiology for General Nursing

All rights reserved. No part of this publication should be reproduced, stored in a retrieval system, or transmitted in any form or by any means: electronic, mechanical, photocopying, recording, or otherwise, without the prior written permission of the authors and the publisher.

First Edition: 2006

9788180615863

Typeset at JPBMP typesetting unit

Printed at Gopsons Papers Ltd., A-14, Sector 60, Noida4

My Students over the years

5Preface

The book Anatomy and Physiology for General Nursing is primarily intended for students of General Nursing, but will also provide a good understanding of physiology as required for nursing practice and for those preparing for CGFNS examination. The book is prepared based on the syllabus recommended for General Nursing by Nursing Council of India.

The book is designed in a comprehensive way to cater the needs of nursing students.

SM Raju

Bindu Madala

6Acknowledgements

At the outset I must express my sincere thanks to Dr Vijay R Madala for having suggested me to write books for nursing students.

It is always a pleasant experience to work with Shri Jitendar P Vij of M/s Jaypee Brothers Medical Publishers (P) Ltd. I also thank the artists of Jaypee Brothers Publishing House for the final touches given to the figures in this book. Indeed the authors thanks every member of the publishing house for his or her sustained efforts in publishing this book.

Finally I like to mention the sustained inspiration provided by my wife Smt Hemavathi AM.

13Introduction to the Study of Anatomy and Physiology

The earliest studies of anatomy and physiology were aimed at treating illnesses and injuries. Such studies set the stage for the development of modern medicine with standardized terms in Greek and Latin.

Anatomy deals with the structure (morphology) of the body and its parts, whereas physiology studies the functions of these parts.

Anatomists rely on observation while physiologists employ experimentation. The functional role of a part depends on how it is constructed.

THE HUMAN BODY PLAN

The human body begins to take shape during the earliest stages of embryonic development. While the embryo is a tiny hallow ball of dividing cells, it begins forming the tissues and organs that compose the human body. By the end of its third week, human embryo has bilateral symmetry (a body plan in which the left and right sides are the mirror images of each other), and is developing vertebrate characteristics that will support an upright body.

The human body is a precisely structured container of chemical reactions.
Biology is the study of living things including the study of the human body.
The study of body structure, which includes size, shape, composition, and perhaps even coloration, is called Anatomy.
The study of how the body function is called Physiology.

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The purpose of this chapter is to enable you to gain an understanding of anatomy and physiology with the emphasis on normal structure and function.

LEVELS OF STRUCTURAL ORGANIZATION () CHEMICAL LEVEL

The chemicals that make up the body may be divided into two major categories: inorganic and organic.

Inorganic chemicals are usually simple molecules made of one or more elements other than carbon. Examples are water, oxygen, carbon dioxide (an exception), and minerals such as iron, calcium, and sodium.
Organic chemicals are often very complex and always contain the elements carbon and hydrogen. Examples are carbohydrates, fats, proteins, and nucleic acids.

Cellular Level

The smallest living units of structure and function are cells. Cells are the smallest living subunits of a multicellular organism such as a human being.

Fig. 1: Levels of structural organization

There are many different types of cells; each is made of chemicals and carries out specific chemical reactions.

Tissue Level

A tissue is a group of cells with similar structure and function. There are four groups of tissue ().

Epithelial tissue cover or line body surfaces; some are capable of producing secretions with specific functions. The outer layer of the skin and sweat glands are examples of epithelial tissue.
Connective tissue connects and supports parts of the body; some transport or store materials. Examples are blood, bone, and adipose tissue (Fat).
Muscle tissue is specialized for contraction, which brings about movement. Examples are skeleton muscles and the heart.
Nerve tissue is specialized to generate and transmit electrochemical impulses that regulate body functions. The examples are brain and optic nerves.

Fig. 2: Structural organisation in tissue

Organ Level

An organ is a group of two or more different types of tissues precisely arranged so as to accomplish specific functions and usually 16have recognizable shape. The examples are heart, brain, kidneys, liver, and lungs.

Organ Systems (System Level)

An organ system is a group of organs that all contribute to a particular function. Examples are the circulatory, respiratory, and digestive systems. Each organ system carries out its own specific function, but for the organism to survive the organ systems must work together; this is called integration of organ system.

Organism Level

Organism level is the most complex level (). All the organ systems of the body functioning with one another constitute the total organism (one living individual).

Fig. 3: Structural organization at organism level

LIFE PROCESSES OR CHARACTERISTICS OF LIFE

All living organisms carry on certain processes that set them apart from nonliving things. The following are several of the more important life processes of humans:

Metabolism is the sum of all the chemical reactions that occur in the body. One phase of metabolism called catabolism provides the energy needed to sustain life by breaking down substances such as food molecules. The other phase called anabolism uses the energy from catabolism to make various substances that form body structures and enable them to function.
Assimilation is the changing of absorbed substances into forms that are chemically different from those that entered body fluids.
Responsiveness is the ability to detect and respond to changes outside or inside the body. Seeking water to quench thirst is a response to water loss from body tissue.
Movement includes motion of the whole body, individual organs, single cells, or even structures inside cells.
Growth refers to an increase in body size. It may be due to an increase in the size of existing cells, the number of cells, or the amount of substance surrounding cells. It occurs whenever an organism produces new body materials faster than old ones are worn out or replaced.
Differentiation is the process whereby unspecialized cells become specialized cells. Specialized cells differ in structure and function from the cells from which they originated.
Reproduction refers either to the formation of new cells for growth, repair, or replacement or to the making of a new individual.
Others Include:
- Respiration—obtaining oxygen.
- Digestion—chemically and mechanically breaking down food substances.
  
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- Absorption—the passage of substances through certain membranes.
- Circulation—the movement of substances within the body in body fluids.
- Excretion—removal of wastes that the body produces.

MAINTENANCE OF LIFE OR SURVIVAL NEEDS

The structures and functions of almost all body parts help to maintain the life of the organism. The only exceptions are an organism's reproductive structures, which ensure that its species will continue into the future.

Life requires certain environmental factors, which includes the following:

Water is the most abundant chemical in the body and it is required for many metabolic processes and provides the environment in which most of them take place. Water also transports substances within the organism and is important in regulating body temperature.
Food is the substances that provide the body with necessary chemicals (Nutrients) in addition to water. Food is used for energy supply, the raw materials for building new living matter, and still others help to regulate vital chemical reactions.
Oxygen is required to release energy from food substances. This energy, in turn, drives metabolic processes. Approximately 20 percent of the air we breathe is oxygen.
Heat (body temperature) is a form of energy; it is a product of metabolic reactions. Normal body temperature is around 37°C or 98°F. Both low or high body temperatures are dangerous to the organism.
Pressure (atmospheric) is necessary for our breathing.

PRINCIPAL ORGAN SYSTEMS OF THE HUMAN BODY

Integumentary system includes the skin and structures derived from it, such as hair, nails, sweat and oil glands. It protects the 19body and forms a barrier to pathogens and chemicals. Helps regulate body temperature, eliminates waste, helps synthesize vitamin D, and receives certain stimuli such as temperature, pressure, and pain.

Skeletal system includes all the bones of the body (206), their associated cartilage, and the joints of the body. Bones support and protect the body, assist in body movement, they also house cells that produce blood cells, and they store minerals.

Muscular system specifically refers to skeletal muscle tissue and tendons. They participate in bringing about movement, maintaining posture, and produces heat.

Circulatory and cardiovascular system includes the heart, blood and blood vessels. Transports oxygen and nutrients to tissues and removes waste.

Lymphatic system is sometimes included with the immune system or circulatory system because it works closely with both systems. The lymph, lymphatic vessels, and structures are organs (spleen and lymph nodes) containing lymph tissue. It cleans and returns tissue fluid to the blood and destroys pathogens that enter the body.

Nervous system includes the brain, spinal cord, nerves, and sense organs, such as the eye and ear. Its function is to interpret sensory information, regulates body functions such as movement by means of electrochemical impulses.

Endocrine system includes all hormone producing glands and cells such as the pituitary gland, thyroid gland, and pancreas. Hormones regulate body functions.

Respiratory system includes the lungs and a series of associated passageways such as the pharynx (throat), larynx (voice box), trachea (windpipe), and bronchial tubes leading into and out of them. Its function is to exchange oxygen and carbon dioxide between the air and blood.20

Digestive system is a long tube called the gastrointestinal (GI) tract and associated organs such as the salivary glands, liver, gallbladder, and pancreas. It breaks down and absorbs food for use by cells and eliminates solid and other waste.

Urinary and excretory systems include the kidneys, urinary bladder, and urethra that together produce, store, and eliminate urine.

Removes waste products from the blood and regulate volume and pH of blood.

Immune system consists of several organs, as well as white blood cells in the blood and lymph. It includes the lymph nodes, spleen, lymph vessels, blood vessels, bone marrow, and white blood cells (lymphocytes). Provides protection against infection and disease.

Reproductive system are the organs that produce, store, and transport reproductive cells (sperm and eggs). Produces eggs and sperm. In women, provides a site for the developing embryo-fetus.

HOMEOSTASIS

All of the above systems function together to help the human body to maintain homeostasis.
A person who is in good health is in a state of homeostasis.
Homeostasis reflects the ability of the body to maintain relative stability and to function normally despite constant changes.
Changes may be external or internal, and the body must respond appropriately.
As we continue to study the human body, keep in mind that the proper functioning of each organ and organ system has a role to perform in maintaining homeostasis.
The human body uses homeostasis mechanisms to maintain its stable internal environment.

Homeostasis mechanisms work much like a thermostat (negative feedback) that is sensitive to temperature and maintains a relative constant water temperature in a water boiler.

ANATOMICAL TERMINOLOGY

To communicate effectively with one another, researchers and clinicians have developed a set of terms to describe anatomy that have precise meaning. Use of these terms assumes the body in the anatomical position (). This means that the body is standing erect, face forward with upper limbs at the sides and with the palms forward.

Fig. 4: Anatomical position

As a standard point or frame of reference, the human body is described as being in the anatomical position when it is standing erect, facing you, feet together flat on the floor, the arms slightly raised from the sides with the palms facing forward. Here is a list of useful directional terms. Know not only what they mean, but also how to correctly use them.

Anatomical Planes ()

Sagittal plane divides the body into right and left halves.
- Midsagittal divides the body right down the middle into equal halves, and
- Parasagittal divides the body into unequal parts.
Coronal (Frontal) plane divides the body into front and back.
Transverse plane divides the body into superior (top) and inferior (bottom) parts.
Supine is lying on the back.
Prone is lying on the abdomen.

Fig. 5: Anatomical planes

RELATIVE POSITION (ORIENTATION AND DIRECTIONAL TERMS)

Terms of relative position describe the location of one body part with respect to another (). This include the following:

Fig. 6: Orientation and directional terms

Superior—means that a body part is above another part or is closer to the head.
Inferior—means that a body part is below another body part or toward the feet.
Anterior—means toward the front.
Ventral—also means toward the front.
Posterior—is the opposite of anterior; it means toward the back.
Dorsal—also is the opposite of anterior; it means toward the back.
Medial—relates to an imaginary midline dividing the body in equal right and left halves, e.g. the nose is medial to the eyes.
Lateral—means toward the side with respect to the imaginary midline, e.g. the ears are lateral to the eyes.
Proximal—describes a body part that is closer to a point of attachment or closer to the trunk of the body than another part, e.g. the elbow is proximal to the wrist.
Distal—is the opposite of proximal. It means that a particular body part is farther from the point of attachment or farther from the trunk of the body than another part, e.g. the fingers are distal to the wrist.

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Superficial—means situated near the surface.
Peripheral—also means outward or near the surface.
Deep—describes parts that are more internal.
Cortex—the outer layer of an organ
Medulla—the inner portion of an organ.

Terms for Common Movements

Flexion: Bending at a joint to approximate the two connected parts together.

Extension: Straightening out from a position of flexion

Abduction: Drawing away from the median axis of the body

Adduction: Bringing towards the median line of the body.

The whole body is built around the bony framework and consists of three main parts:

The head and neck
The trunk that includes chest, abdomen and pelvis
Limbs that includes upper and lower limbs.

Skull

The skull consists of cranium that protects brain and eyes, and the mandible that is hinged to the skull. The movement of mandible is essential for chewing and speech.

THORAX

Thorax is the upper part of the trunk, its wall is made of bony frame work that houses the lungs and heart apart from the contents of the mediastinum.

Anteriorly the thorax is bounded by sternum, costal cartilage and front ends of the ribs.
Posteriorly it is bounded by dorsal part of the vertebral column made of twelve thoracic vertebral bones and intervertebral discs.

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Laterally bounded by twelve ribs and intervertebral muscles.
Superiorly bounded by the root of the neck with its muscles and blood vessels.
Inferiorly it is bounded by the diaphragm, which separates the thorax from the abdomen. Diaphragm is a dome shaped muscular structure through the esophagus, aorta and inferior vena cava pass through.

Contents of Thorax

The central part of the thoracic cavity is occupied by the mediastinum that extends anteriorly from behind the sternum to vertebral column posteriorly. On either side of the sternum lungs are situated.
The heart is situated in the left side of the mediastinum enclosed in a fibrous bag called pericardium.
Trachea enters the thorax through its superior opening from the neck and passes down along the posterior aspect of the mediastinum until it divides into left and right bronchus that enter the two lungs.
Esophagus as continuation of pharynx enters the thorax through its superior opening from the neck. It lies just in front of and to the left of the vertebral column and behind the trachea. It enters the abdomen through an opening in the diaphragm to join the stomach.
Aorta the continuation of arch of the aorta, the superior and inferior vena cava, the thoracic duct and the lymph nodes are the other contents of the thorax.

Abdomen

Abdomen is the biggest cavity in the body, which is arbitrarily divided into abdomen proper and pelvis. The pelvis is bounded posteriorly by the sacrum, ischium on either sides, pubic bone in the front and muscles of the pelvic floor inferiorly.26

Abdomen is bounded anteriorly by the muscles of the abdominal wall; the rectus, internal and external oblique, and transverses on either side.
It is bounded posteriorly by the lumbar part of the vertebral column, psoas, quadratum lumborum and iliacus muscles.
Superiorly it is bounded by the diaphragm.
Inferiorly the abdominal cavity is continuous with the superior opening of the pelvis.

Contents of the Abdomen

Stomach and intestine
Liver, gall-bladder and spleen
The pancreas, kidneys, adrenal glands, abdominal aorta and inferior vena cava. All of these structures lie posterior to the peritoneum.

Contents of the Pelvic Cavity

The sigmoid colon, pelvic colon and the rectum
The urinary bladder
Reproductive organs in the female
Some loops of the small intestine.

BODY CAVITIES

Many organs and organ systems in the human body are housed in compartments called body cavities ().
These cavities protect delicate internal organs from injuries and from the daily wear of walking, jumping, or running.
The body cavities also permit organs such as the lungs, the urinary bladder, and the stomach to expand and contract while remaining securely supported.
The body can be divided into an appendicular portion (upper and lower limbs) and an axial portion (head, neck, and trunk), which contains a dorsal and a ventral cavity.

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Fig. 7: Anatomical cavities

Organs within these cavities are called viscera.
- The dorsal cavity can be divided into the cranial cavity and vertebral canal.
- The ventral cavity is made up of a thoracic cavity (mediastinum divides the thorax into right and left halves) and an abdominopelvic cavity (divided into the abdominal cavity and the pelvic cavity) separated by the diaphragm.
- Smaller cavities within the head include the oral cavity, nasal cavity, orbital cavities, and middle ear cavities.

REVIEW

Define anatomy and physiology, and explain how they are related. List and describe the major characteristics of life. Define homeostasis, and explain its importance to survival. Describe a 28homeostatic mechanism, list and describe the four types of tissues that make up the human body. Explain how tissues, organs, and organ systems are organized. Summarize the functions of the primary organ systems in the human body. Name and locate four human body cavities, and describe the organs that each contain. Properly use terms that describe relative positions, body sections, and body regions.

Chapter Notes