N A O M I E . B A L A B A N A N D J A M E S B O B I C K

Detroit

THE

HANDY ANATOMYANSWER

BOOK

THE

HANDY ANATOMYANSWER

BOOK

Copyright © 2008 by Visible Ink Press®

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Managing Editor: Kevin S. HileArt Director: Mary Claire KrzewinskiTypesetting: Marco Di VitaISBN 978-1-57859-190-9

Cover images:Cell graphic courtesy of Cohen B.J., and Wood, D.L. Memmler’s The Human Bodyin Health and Disease. 9th Ed. Philadelphia: Lippincott, Williams & Wilkins,2000.

Brain illustration courtesy of Cohen, B.J. Medical Terminology. 4th Ed.Philadelphia: Lippincott, Williams & Wilkins, 2003.

All other images courtesy of iStockphoto.com

Library of Congress Cataloging-in-Publication DataBalaban, Naomi E.The handy anatomy answer book / Naomi E. Balaban and James E. Bobick

p. ; cm.Includes bibliographical references and index.ISBN 978-1-57859-190-9 (alk. paper)1. Human anatomy—Miscellanea. 2. Physiology—Miscellanea. I. Balaban,Naomi E. II. Title. [DNLM: 1. Anatomy—Examination Questions. 2. Anatomy. 3.Physiology—Examination Questions. 4. Physiology. QS 4 B663h 2008]

QM23.2.B62 2008611.0076—dc22

2008001595

Printed in the United States of America

10 9 8 7 6 5 4 3 2 1

BACKGROUND FACTS 1History … Levels of Organization …Anatomical Terminology … ImagingTechniques

BASIC BIOLOGY 17Chemistry for Biology … BiologicalCompounds … Cells … Tissues …Membranes … Homeostasis

INTEGUMENTARYSYSTEM 41Introduction … Skin Structure … SkinFunction … Nails … Hair … AccessoryGlands

SKELETAL SYSTEM 59Introduction … Bone Basics … AxialSkeleton … Appendicular Skeleton … Joints

MUSCULAR SYSTEM 83Introduction … Organization of Muscles …Muscle Structure … Muscle Function

NERVOUS SYSTEM 105Introduction … Neuron Function …Central Nervous System … The Brain …Spinal Cord … Peripheral Nervous System:Somatic Nervous System … PeripheralNervous System: Autonomic NervousSystem … Learning and Memory … Sleepand Dreams

SENSORY SYSTEM 141Introduction … Smell … Taste … Hearing… Vision

ENDOCRINE SYSTEM 161Introduction … Hormones … PituitaryGland … Thyroid and Parathyroid Glands… Adrenal Glands … Pancreas … PinealGland … Reproductive Organs … OtherSources of Hormones

CARDIOVASCULARSYSTEM 185Introduction … Blood … The Heart …Blood Vessels … Circulation ix

Contents

FOREWORD xiACKNOWLEDGMENTS xiii

LYMPHATIC SYSTEM 209Introduction … Lymphatic Vessels andOrgans … Nonspecific Defenses … SpecificDefenses … Allergies

RESPIRATORY SYSTEM 233Introduction … Structure and Function …Respiration and Breathing … SoundProduction

DIGESTIVE SYSTEM 251Introduction … Upper Gastro-IntestinalTract … Lower Gastro-Intestinal Tract …Accessory Glands … Metabolism andNutrition

URINARY SYSTEM 279Introduction … Kidneys … AccessoryOrgans … Urine and Its Formation

REPRODUCTIVESYSTEM 291Introduction … Male Reproductive System… Female Reproductive System … SexualResponse and Conception

HUMAN GROWTH ANDDEVELOPMENT 311Introduction … Prenatal Development—Embryonic Period … PrenatalDevelopment—Fetal Stage … Birth andLactation … Postnatal Development

x

GLOSSARY 335INDEX 341

Pick up a magazine or newspaper, turn on the radio or television, or access med-ical and health information on the Internet and you will find that the human bodyis definitely in the news. Artificial hearts, dietary supplements, stem cell research,genetic engineering, arthroscopic surgery, and many other intriguing subjects onhuman biology and health are talked about daily. Our bodies seem to be constantlyon our minds! The Handy Anatomy Answer Book is here to help you unravel thecomplexities and mysteries of how your body works.

Our interest in and understanding of the human body has a long and detailedhistory going back to the ancient Greeks Aristotle and Galen, who first studied thestructure and function of our species. From this starting point, however, the scien-tific study of the body progressed slowly. It wasn’t until the sixteenth century thatthe foundations of modern anatomy were laid by Andreas Vesalius; and it wasn’tuntil the century after that when William Harvey discovered how blood circulatesin the body. Finally, in the nineteenth century, anatomy and physiology became dis-tinct scientific disciplines.

As techniques for making more accurate observations and performing carefulexperiments evolved, knowledge of the human body expanded rapidly. And as ourknowledge expanded, so did the vocabulary to describe what medical doctors werediscovering. Using the root languages of Greek and Latin, soon there was a plethoraof complex terms describing body parts, their precise locations, and their functions.

The Handy Anatomy Answer Book helps make the language of anatomy—aswell as physiology and pathology—more understandable and less intimidating tothe general reader, while answering over one thousand questions on all the majorbody systems.

In this informative book, you’ll find answers to such intriguing questions as:Who discovered how muscles work? What is the largest nerve in the body? Howmuch air can your lungs hold? What are the primary sensations of taste? Who isconsidered the founder of physiology? How many bones are in the human body?The Handy Anatomy Answer Book also includes fascinating trivia. Do identicaltwins share the same fingerprints? What tissues in your body can regenerate? Doesbrain size affect intelligence? xi

Foreword

HISTORY

Which scientific disciplines study the human body?The scientific disciplines of anatomy and physiology study the human body. Anato-my (from the Greek ana and temnein, meaning “to cut up”) is the study of thestructure of the body parts, including their form and organization. Physiology(from the Latin, meaning “the study of nature”) is the study of the function of thevarious body parts and organs. Anatomy and physiology are usually studied togeth-er to achieve a complete understanding of the human body.

How is the field of anatomy divided into subdivisions?The field of anatomy is generally divided into macroscopic, or gross anatomy (notrequiring a microscope), and microscopic anatomy. Gross anatomy includes thesubdivisions of regional anatomy, systemic anatomy, developmental anatomy, andclinical anatomy. Regional anatomy studies specific regions of the body, such as thehead and neck or lower and upper limbs. Systemic anatomy studies different bodysystems, such as the digestive system and reproductive system. Developmentalanatomy describes the changes that occur from conception through physical matu-rity. Clinical anatomy includes medical anatomy (anatomical features that changeduring illness) and radiographic anatomy (anatomical structures seen using variousimaging techniques).

The two major subdivisions of microscopic anatomy are cytology and histology.Cytology (from the Greek cyto, meaning “cell”) is the study and analysis of theinternal structure of individual cells. Histology (from the Greek histos, meaning“web”) is the study and examination of tissues. 1

BACKGROUNDFACTS

What are some specialtiesof physiology?Specialties and subdivisions of physiolo-gy include cell physiology, special phys-iology, systemic physiology, and patho-logical physiology, often called simplypathology. Cell physiology is the studyof the functions of cells, including bothchemical processes within cells andchemical interactions between cells.Special physiology is the physiologicalstudy of specific organs, such as cardiacphysiology, which is the study of heartfunction. Systemic physiology is com-parable to systemic anatomy since it isthe study of the functions of differentbody systems, such as renal physiologyand neurophysiology. Pathology (from

the Greek pathos, meaning “suffering” or “disease”) is the study of the effects of dis-eases on organs or systems and diseased cells and tissues.

When did the study of anatomy and physiology first become acceptedas sciences?Anatomy and physiology were first accepted as sciences during ancient Greek times.Hippocrates (c. 460–377 B.C.E.), who is considered the father of medicine, estab-lished medicine as a science, separating it from religion and philosophy. His appli-cation of logic and reason to medicine was the beginning of observational medicine.

What were Aristotle’s contributions to anatomy?Aristotle (384–322 B.C.E.) wrote several works laying the foundations for compara-tive anatomy, taxonomy, and embryology. He investigated carefully all kinds of ani-mals, including humans. His works on life sciences, On Sense and Sensible Objects,On Memory and Recollection, On Sleep and Waking, On Dreams, On Divination byDreams, On Length and Shortness of Life, On Youth and Age, and On Respiration,are collectively called Parva Naturalia.

Who is considered the father of physiology?The Greek physician and anatomist Erasistratus (304–250 B.C.E.) is considered thefather of physiology. Based on his numerous dissections of human cadavers, heaccurately described the brain, including its cavities and membranes, stomachmuscles, and the differences between motor and sensory nerves. He understoodcorrectly that the heart served as a pump to circulate blood. Anatomical researchended with Erasistratus until the thirteenth century, in a large part because of pub-2

Most people consider Hippocrates the founder of thediscipline of medicine; and the Hippocratic oath—the codeof ethics followed by physicians—is also named after him.© iStockphoto.com/Phil Sigin.

lic opinion against the dissection ofhuman cadavers.

Whose work during the Roman erabecame the authority on anatomy?Galen (130–200), a Greek physician,anatomist, and physiologist living dur-ing the time of the Roman Empire, wasone of the most influential and authori-tative authors on medical subjects. Hiswritings include On Anatomical Proce-dures, On the Usefulness of the Parts ofthe Body, On the Natural Faculties, andhundreds of other treatises. Sincehuman dissection was forbidden, Galenmade most of his observations on differ-ent animals. He correctly describedbones and muscles and observed muscles working in contracting pairs. He was alsoable to describe heart valves and structural differences between arteries and veins.While his work contained many errors, he provided many accurate anatomicaldetails that are still regarded as classics. Galen’s writings were the accepted stan-dard text for anatomical studies for 1,400 years.

Who became known as the “reformer of anatomy” duringthe Renaissance?Andreas Vesalius (1514–1564) became known as the “reformer of anatomy” duringthe Renaissance. His masterpiece and most famous work, De Humani Corporis Fab-rica, published in 1543, described various body systems and individual organs. Italso included beautiful anatomical illustrations. Vesalius challenged many ofGalen’s teachings, which had become accepted as fact though they were incorrect.

Who improved the microscope in a way that greatly impacted anatomyand physiology studies?Anton van Leeuwenhoek (1632–1723) was a Dutch microscopist and scientist.Although he did not invent the microscope, he greatly improved the capability ofthe microscope. His expert skill in grinding lenses achieved a magnification of 270times, which was far greater than any other microscope of the era. He was able toobserve bacteria, striations in muscle, blood cells, and spermatozoa.

What discovery of the 17th century helped establish the scienceof physiology?The English physician William Harvey (1578–1657) published On the Movement ofthe Heart and Blood in Animals in 1628. This important medical treatise proved 3

The Greek philosopher Aristotle helped lay the foundationsof several scientific fields, including anatomy. ©iStockphoto.com/Phil Sigin.

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that blood continuously circulatedwithin the vessels. Harvey’s dis-coveries contradicted many beliefsabout blood circulation that datedback to the time of Galen. Harveyis considered the father of modernphysiology for introducing theexperimental method of scientificresearch.

Who is considered the founderof experimental medicineand physiology?The French physiologist ClaudeBernard (1813–1878) is creditedwith originating the experimentalapproach to medicine and estab-lishing general physiology as a dis-tinct discipline. His classic work,Introduction to the Study ofExperimental Medicine, was pub-lished in 1865. He was elected tothe Académie Française in 1869for this work.

What was the firstprofessional organization ofphysiologists?

The first organization of physiologists was the Physiological Society founded in1876 in England. In 1878 the Journal of Physiology began publication as the firstjournal dedicated to reporting results of research in physiology. The Americancounterpart, the American Physiological Society, was founded in 1887. The Ameri-can Physiological Society first sponsored publication of the American Journal ofPhysiology in 1898.

LEVELS OF ORGANIZATION

What are the levels of structural organization in vertebrate animals,including humans?Every vertebrate animal has four major levels of hierarchical organization: cell, tis-sue, organ, and organ system. Each level in the hierarchy is of increasing complex-ity, and all organ systems work together to maintain life.4

The development of the modern microscope vastly improvedscientists’ knowledge of bacteria, viruses, cells, and small anatomicalstructures. © iStockphoto.com/Christopher Pattberg Fotodesign.

What is a cell?A cell is a membrane-bound unit that contains hereditary material (DNA) and cyto-plasm; it is the basic structural and functional unit of life. See chapter 2 for more details.

What are the four major types of tissue?A tissue (from the Latin texere,, meaning “to weave”) is a group of similar cells thatperform a specific function. The four major types of tissue are epithelial, connec-tive, muscle, and nerve. Each type of tissue performs different functions. 5

Cells in the human body organize themselves into increasingly complex structures and systems. (From Premkumar K. TheMassage Connection Anatomy and Physiology. Baltimore: Lippincott, Williams & Wilkins, 2004.)

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What are the general characteristics of the different types of tissue?Each of the four major types of tissue have different functions, are located in differ-ent parts of the body, and have certain distinguishing features. The table belowexplains these differences.

Characteristics of Tissues

Tissue Function Location Distinguishing Features

Epithelial Protection, secretion, Covers body surfaces, Lacks blood vesselsabsorption, excretion covers and lines

internal organs,compose glands

Connective Bind, support, protect, Widely distributed Matrix between cells, fill spaces, store fat, throughout the body good blood supplyproduce blood cells

Muscle Movement Attached to bones, Contractilein the walls of hollowinternal organs, heart

Nervous Transmit impulses Brain, spinal cord, Cells connect to each for coordination, nerves other and other bodyregulation, integration, partsand sensory reception

What is an organ?An organ is a group of several different tissues working together as a unit to per-form a specific function or functions. Each organ performs functions that none ofthe component tissues can perform alone. This cooperative interaction of differenttissues is a basic feature of animals, including humans. The heart is an example ofan organ. It consists of cardiac muscle wrapped in connective tissue. The heartchambers are lined with epithelium. Nerve tissue controls the rhythmic contrac-tions of the cardiac muscles.6

What is the cell theory?

The cell theory states that the cell is the fundamental component of all lifeand all organisms are made up of cells. There are three basic principles to

the cell theory. First, the cell is the simplest collection of matter that can live.There are diverse forms of life existing as single-celled organisms. More com-plex organisms, including plants and animals, are multicellular cooperativescomposed of diverse, specialized cells that could not survive for long on theirown. Secondly, all cells come from preexisting cells and are related by divisionto earlier cells that have been modified in various ways during the long evo-lutionary history of life on earth. Finally, all of the life processes of an organ-ism occur fundamentally at the cellular level.

What is an organ system?An organ system is a group of organs working together to perform a vital body func-tion. There are twelve major organ systems in the human body.

Organ Systems and Their Functions

Organ System Components Functions

Cardiovascular and Heart, blood, Transports bloodcirculatory and blood vessels throughout the body, supplying

nutrients and carrying oxygen to thelungs and wastes to kidneys

Digestive Mouth, esophagus, Ingests food and breaks it down intostomach, intestines, smaller chemical unitsliver, and pancreas

Endocrine Pituitary, adrenal, Coordinates and regulates the activitiesthyroid, and other of the bodyductless glands

Excretory Kidneys, bladder, Removes wastes from the bloodstreamand urethra

Immune Lymphocytes, Removes foreign substancesmacrophages, andantibodies

Integumentary Skin, hair, nails, Protects the bodyand sweat glands

Lymphatic Lymph nodes, Captures fluid and returns it to thelymphatic capillaries, cardiovascular systemlymphatic vessels,spleen, and thymus

Muscular Skeletal muscle, Allows body movementscardiac muscle,and smooth muscle

Nervous Nerves, sense organs, Receives external stimuli, processesbrain, and spinal cord information, and directs activities

Reproductive Testes, ovaries, and Carries out reproductionrelated organs

Respiratory Lungs, trachea, and Exchanges gases—captures oxygen (O2)other air passageways and disposes of carbon dioxide (CO2)

Skeletal Bones, cartilage, and Protects the body and provides supportligaments for locomotion and movement

ANATOMICAL TERMINOLOGY

What is the anatomical position?Anatomists universally defined the anatomical position as the body standing erect,facing forward, the feet are together and parallel to each other, the arms are at theside of the body with the palms facing forward. All directional terms that describe 7

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the relationship of one body part to another assume the body is in the anatomicalposition.

What are the commonly used directional terms to describe the location ofone body part in relation to another body part?Standard directional terms are used to describe the location of one body part inrelation to another body part. Most directional terms occur as pairs with one termof the pair having the opposite meaning of the other term.

Directional Terms of the Body

Term Definition Example

Superior (cranial Toward the head The head is superior to the neckor cephalic)Inferior (caudal) Away from the head; The neck is inferior to the head

toward the feetAnterior (ventral) Toward the front The toes are anterior to the heelPosterior (dorsal) Toward the back The heel is posterior to the toesMedial Toward the midline of the body The nose is medial to the eyesLateral Away from the midline of The eyes are lateral to the nose

the body; towards the sidesProximal Toward the trunk of the The shoulder is proximal to the

body; nearer the attachment elbowof an extremity to the trunk

Distal Away from the trunk The wrist is distal to the shoulderof the body; further fromthe attachment of an extremityto the trunk

Superficial Near the surface of the body The skin is superficial to the muscles(external)Deep (internal) Farther from the surface The heart is deeper than the ribs

of the body8

Why are body planes importantfor identifying anatomical structure?

In order to observe and study the structural arrangement of the internalorgans, the body may be divided and sectioned (or cut) along three funda-

mental planes. These planes are the midsagittal (median) plane, the coronal(frontal) plane, and the transverse (horizontal) plane. The midsagittal planedivides the body lengthwise into right and left sides. A sagittal section placedoff-center divides the body into asymmetrical right and left sides. The coronalplane divides the body into front (anterior) and back (posterior) sections. Thetransverse plane divides the body into upper (superior) and lower (inferior)sections. It is at right angles to the sagittal and frontal planes.