Art labeling activity plasma membrane transport

Anatomy Homework Packet

TWELFTH EDITION

Elaine N. Marieb Suzanne M. Keller

Essentials of Human Anatomy & Physiology

GLOBAL EDITION

Learn the Essential What, How & Why of Human Anatomy & Physiology

With the Twelfth Edition of Essentials of Human Anatomy & Physiology, science educator Suzanne Keller joins bestselling author Elaine Marieb in helping learners focus on the What, How & Why of A&P, without getting sidetracked in details.

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When most people hear the term cardio-vascular system, they immediately think of the heart. We have all felt our own heart “pound” from time to time when we are ner- vous. The crucial importance of the heart has been recognized for ages. However, the cardiovascular system is much more than just the heart, and from a scientific and medical standpoint, it is important to understand why this system is so vital to life.

Night and day, minute after minute, our tril- lions of cells take up nutrients and excrete wastes. Although the pace of these exchanges slows dur- ing sleep, they must go on continuously: when they stop, we die. Cells can make such exchanges

only with the interstitial fluid in their immediate vicinity. Thus, some means of changing and “refreshing” these fluids is necessary to renew the nutrients and prevent pollution caused by the buildup of wastes. Like a bustling factory, the body must have a transportation system to carry its various “cargoes” back and forth. Instead of roads, railway tracks, and subways, the body’s delivery routes are its hollow blood vessels.

Most simply stated, the major function of the cardiovascular system is transportation. Using blood as the transport vehicle, the system carries oxygen, nutrients, cell wastes, hormones, and many other substances vital for body homeostasis to and from the cells. The force to move the blood

The Cardiovascular System

WHAT

HoW

WHY

The cardiovascular system delivers oxygen and

nutrients to the body tissues and carries away wastes such as carbon dioxide

via blood.

The heart pumps blood throughout the body in blood vessels. Blood flow

requires both the pumping action of the heart and changes in

blood pressure.

If the cardiovascular system cannot perform its

functions, wastes build up in tissues. Body organs fail to function properly,

and then, once oxygen becomes depleted, they will die.

InSTruCTorS

New Building Vocabulary Coaching Activities for this chapter are assignable in

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NEW! What, How & Why chapter previews introduce key examples of anatomy and physiology concepts that will be covered in the chapter. This technique helps learners hone in on what they are studying, how it functions, and why it is important for them to learn.

NEW! Building Vocabulary Coaching Activities in Pearson Mastering A&P help students learn the essential language of A&P.

See p. 382.

Throughout every chapter, the text’s conversational writing style and straightforward explanations have been strengthened with familiar analogies and abundant mnemonic cues to help students learn and remember concepts.

UPDATED! Exceptionally clear photos and illustrations, including dozens of new and improved figures, present concepts and processes at the right level of detail. Many figures from the text are assignable as Art- Labeling Activities in Pearson Mastering A&P.

Unique Concept Links reinforce previously-learned concepts and help students make connec- tions across body systems while learning new material.

Focus on Essential A&P Concepts

Chapter 4: Skin and Body Membranes 137

4

Cutaneous membrane (skin)

Mucosa

Parietal layer

Visceral layer

Serous fluid

(a) Cutaneous membrane (the skin) covers the body surface.

(d) A fist thrust into a limp balloon demonstrates the relationship between the parietal and visceral serous membrane layers.

(c) Serous membranes line body cavities closed to exterior.

(b) Mucous membranes line body cavities open to the exterior.

Outer balloon wall (comparable to parietal serosa)

Air (comparable to serous cavity)

Inner balloon wall (comparable to visceral serosa)

Figure 4.1 Classes of epithelial membranes.

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282 Essentials of Human Anatomy and Physiology

Figure 7.21 Schematic of ascending (sensory) and descending (motor) pathways between the brain and the spinal cord.

Cerebral cortex (gray matter)

Thalamus

White matter

Interneuron carrying response to motor neuron

Cell body of sensory neuron in sensory ganglion

Skin

Nerve

Sensory receptors

Motor output

Muscle

Interneuron Motor neuron cell body

Gray matter White matter

Interneuron carrying sensory information to cerebral cortex

Interneuron carrying response to motor neurons

Integration (processing and interpretation of sensory input) occurs

Interneuron carrying sensory information to cerebral cortex

Brain stem

Cerebrum

Cervical spinal cord

➔ConCeptLinkThe terms for the connective tissue coverings of a nerve should seem familiar: We discussed similar struc-tures in the muscle chapter (Figure 6.1, p. 209). Names of muscle structures include the root word mys, whereas the root word neuro tells you that the struc- ture relates to a nerve. For example, the endomysium covers one individual muscle fiber, whereas the endo- neurium covers one individual neuron fiber. ➔

Like neurons, nerves are classified according to the direction in which they transmit impulses. Nerves that carry impulses only toward the CNS are called sensory (afferent) nerves, whereas those that carry only motor fibers are motor (efferent) nerves. Nerves carrying both sensory and motor fibers are called mixed nerves; all spi- nal nerves are mixed nerves.

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See p. 137.

See p. 282.

UPDATED! Homeostatic Imbalance discussions are clinical examples that revisit the text’s unique theme by describing how the loss of homeostasis leads to pathology or disease. Related assessment questions are assignable in Pearson Mastering A&P, along with Clinical Case Study coaching activities.

Explore Essential Careers and Clinical Examples

To inspire and inform students who are preparing for future healthcare careers, up-to-date clinical applications are integrated in context with discussions about the human body.

Focus on Careers essays feature conversations with working professionals and explain the relevance of anatomy and physiology course topics across a wide range of allied health careers. Featured careers include:

Ch. 2 Pharmacy Technician Ch. 4 Medical Transcriptionist Ch. 5 Radiologic Technologist Ch. 8 Physical Therapy Assistant Ch. 10 Phlebotomy Technician Ch. 15 Licensed Practical Nurse

Students can visit the Pearson Mastering A&P Study Area for more information about career options that are relevant to studying anatomy and physiology.

See p. 295.

See p. 82.

Pearson Mastering A&P improves results by engaging students before, during, and after class.

Continuous Learning Before, During, and After Class

Instructors can further encourage students to prepare for class by assigning NEW! Building Vocabulary activities, reading questions, art labeling activities, and more.

Before Class

Dynamic Study Modules enable students to study more effectively on their own. With the Dynamic Study Modules mobile app, students can quickly access and learn the concepts they need to be more successful on quizzes and exams. NEW! Instructors can now select which questions to assign to students within each module.

During Class

After Class A wide variety of interactive coaching activities can be assigned to students as homework, including Art-Labeling Activities, Interactive Physiology 2.0 tutorials, Clinical Case Studies, and activities featuring A&P Flix 3-D movie- quality animations of key physiological processes.

with Pearson Mastering A&P

NEW! Learning Catalytics is a “bring your own device” (laptop, smartphone, or tablet) engagement, assessment, and classroom intelligence system. Students use their device to respond to open-ended questions and then discuss answers in groups based on their responses. Visit learningcatalytics.com to learn more.

Media references in the text direct learners to digital resources in the Pearson Mastering A&P Study Area, including practice tests and quizzes, flashcards, a complete glossary, and more.

NEW! Interactive Physiology 2.0

Practice Anatomy Lab (PAL™ 3.0) is a virtual anatomy study and practice tool that gives students 24/7 access to the most widely used lab specimens, including the human cadaver, anatomical models, histology, cat, and fetal pig. PAL 3.0 is easy to use and includes built-in audio pronunciations, rotatable bones, and simulated fill-in-the- blank lab practical exams.

A&P concepts come to life with Pearson Mastering A&P

NEW! Interactive Physiology 2.0 helps students advance beyond memorization to a genuine understanding of complex physiological processes. Fun, interactive tutorials, games, and quizzes give students additional explanations to help them grasp difficult concepts. IP 2.0 features brand-new graphics, quicker navigation, and more robust interactivity.

Access the complete textbook online with the eText on Pearson Mastering A&P

Powerful interactive and customization functions include instructor and student note-taking, highlighting, bookmarking, search, and links to glossary terms.

Additional Support for Students and Instructors

The perfect companion to Essentials of Human Anatomy & Physiology, this engaging interactive workbook helps students get the most out of their study time. The Twelfth Edition includes NEW! crossword puzzles for every chapter, along with coloring activities, self-assessments, “At the Clinic” questions, and unique “Incredible Journey” visualization exercises that guide learners into memorable explorations of anatomical structures and physiological functions.

• All of the figures, photos, and tables from the text in JPEG and PowerPoint® formats, in labelled and unlabeled versions, and with customizable labels and leader lines

• Step-edit Powerpoint slides that present multi-step process figures step-by-step

• Clicker Questions and Quiz Show Game questions that encourage class interaction

• A&PFlix™ animations bring human anatomy and physiology concepts to life

• Customizable PowerPoint® lecture outlines save valuable class prep time

• A comprehensive Instructor’s Guide includes lecture outlines, classroom activities, and teaching demonstrations for each chapter.

• Test Bank provides a wide variety of customizable questions across Bloom’s taxonomy levels. Includes art labeling questions, and available in Microsoft® Word and TestGen® formats.

NEW! Anatomy & Physiology Coloring Workbook Twelfth Edition, Global Edition by Elaine N. Marieb and Simone Brito

The Instructor Resources Area in Pearson Mastering A&P includes the following downloadable tools:

NEW! IN FULL COLOR! Essentials of Human Anatomy & Physiology Laboratory Manual Seventh Edition by Elaine N. Marieb and Pamela B. Jackson

This popular lab manual provides 27 exercises for a wide range of hands-on laboratory experiences, designed especially for a short A&P Lab course. This edition, which includes a Histology Atlas with 55 photomicrographs, features NEW! full-color illustrations, photos, and page design that help students navigate and learn the material faster and easier than ever before. Each concise lab exercise includes a Pre-Lab Quiz, brief background information, integrated learning objectives, student-friendly review sheets, and more.

ELAINE N. MARIEB, R.N., Ph.D., hOLYOKE COMMUNITY COLLEGE

SUZANNE M. KELLER, Ph.D., INDIAN hILLS COMMUNITY COLLEGE

ESSENTIALS OF HUMAN ANATOMY

& PHYSIOLOGY

TWELFTH EDITION GLOBAL EDITION

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Authorized adaptation from the United States edition, entitled Essentials of Human Anatomy & Physiology, 12th edition, ISBN 9780134395326, by Elaine N. Marieb and Suzanne M. Keller, published by Pearson Education © 2018.

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About the Authors

Elaine Marieb After receiving her Ph.D. in zoology from the University of Massachusetts at Amherst, Elaine N. Marieb joined the faculty of the Biological Science Division of Holyoke Community College. While teaching at Holyoke Community College, where many of her students were pursu- ing nursing degrees, she developed a desire to bet- ter understand the relationship between the scientific study of the human body and the clinical aspects of the nursing practice. To that end, while continuing to teach full time, Dr. Marieb pursued her nursing education, which culminated in a Master of Science degree with a clinical specializa- tion in gerontology from the University of Massa- chusetts. It is this experience that has informed the development of the unique perspective and acces- sibility for which her publications are known.

Dr. Marieb has given generously to provide oppor- tunities for students to further their education. She funds the E. N. Marieb Science Research Awards at Mount Holyoke College, which promotes research by undergraduate science majors, and has underwritten renovation of the biology labs in Clapp Laboratory at that college. Dr. Marieb also contributes to the Univer- sity of Massachusetts at Amherst, where she gener- ously provided funding for reconstruction and instrumentation of a cutting-edge cytology research laboratory. Recognizing the severe national shortage of nursing faculty, she underwrites the Nursing Schol- ars of the Future Grant Program at the university. In January 2012, Florida Gulf Coast University named a new health professions facility in her honor. The Dr. Elaine Nicpon Marieb Hall houses several specialized laboratories for the School of Nursing, made possible by Dr. Marieb’s generous support.

Suzanne Keller Suzanne M. Keller began her teaching career while she was still in graduate school at the University of Texas Health Science Center in San Antonio, Texas. Inspired by her life- long passion for learning, Dr. Keller quickly adopted a teaching style focused on translating challenging concepts into easily understood parts using analogies and stories from her own experi- ences. An Iowa native, Dr. Keller uses her expertise to teach microbiology and anatomy and physiol- ogy at Indian Hills Community College, where most of her students are studying nursing or other health science programs.

Dr. Keller values education as a way for students to express their values through the careers they pursue. She supports those endeavors both in and out of the classroom by participating in her local Lions Club, by donating money to the Indian Hills Foundation to fund scholarships, and by financially supporting service-learning trips for students. Dr. Keller also enjoys sponsoring children in need with gifts for the holidays.

Dr. Keller is a member of the Human Anatomy and Physiology Society (HAPS) and the Iowa Acad- emy of Science. Additionally, while engaged as an author, Dr. Keller has served on multiple advisory boards for various projects at Pearson and has authored assignments for the Pearson Mastering A&P online program. When not teaching or writ- ing, Dr. Keller enjoys reading, trav eling, family gatherings, and relaxing at home under the watch- ful eyes of her two canine children.

12

New to the Twelfth Edition

This edition has been thoroughly updated. New “What, How, Why” art opens each chapter, highlighting key concepts relating to the chapter topic. Other specific chapter-by-chapter changes include the following:

• New colors used in Figure 3.14 DNA images to help students track new and old strands of DNA.

• New description of each chromosome being composed of two sister chromatids.

• New explanation of protein synthesis includes the role of the large ribosomal subunit in peptide bond formation.

• New Figure 3.18 descriptions of nuclei lining up in simple columnar and not lining up in pseudostratified epithelia.

• New description of cell shapes in different layers of stratified epithelia as “squished” and variable.

• New analogy for mucus produced by goblet cells as a “sticky trap” for dust and debris.

• New Figure 3.19 labels for osteocytes, the elastic and collagen fibers in areolar connective tissue, and the fluid matrix of blood; new art for dense fibrous connective tissue.

• New analogy for reticular tissue as “cellular bleachers” where other cells rest to monitor the body.

• Updated Figure 3.21 to include the term neuroglia to describe supporting cells.

• New information added to Figure 3.22: cartilage added to the connective tissue list and two major hallmarks of each of the four tissue types.

• New example of atrophy: when a broken leg is in a cast, lack of use causes muscles to atrophy during healing.

• Revised “A Closer Look: Cancer—An Intimate Enemy” and updated art. • New “Short Answer Essay” questions on the components of the

plasma membrane and their functions and on contrasting cytokinesis, interphase, and mitosis.

• New “Critical Thinking and Clinical Application” question on IV fluids and tonicity.

• New “Did You Get It?” questions throughout the chapter.

Chapter 4: Skin and Body Membranes • New Figure 4.1 on epithelial membranes. • New description of sensory receptors as part of nervous system

including a list of the stimuli detected. • New text updates on Figure 4.4 on epidermal structure; included a

new figure question on stratum lucidum. • New analogy for epidermal dendritic cells as “sentries” guarding

the skin. • New photo of stage 2 decubitus ulcer added to Homeostatic

Imbalance 4.2. • New layout for Figure 4.7 combining scanning electron micrograph

of hair shaft with existing art of the hair root and follicle. • New discussion of fourth-degree burns. • New criteria for determining whether a burn is critical, including

circumferential burns, burns of the airway, and burns to the genital area.

• New images of basal cell and squamous cell carcinoma in Figure 4.11.

• New component added to ABCDE rule: now includes “Evolution,” changes in a skin lesion over time.

• New “Short Answer Essay” questions on the risks of full-thickness burns, contrasting eccrine and apocrine sweat glands, and the relative severity of different skin infections.

• New “Critical Thinking and Clinical Application” question on burns. • New “Did You Get It?” questions throughout the chapter.

Chapter 5: The Skeletal System • Updated description of long bones. • New analogy comparing lubrication over articular cartilage at

joints to a slick marble floor.

Chapter 1: The Human Body: An Orientation • Updated description of the integumentary system to include

vitamin D production in the presence of sunlight. • Updated definition of the term crural to specify the anterior leg,

or shin. • New “Critical Thinking and Clinical Application” question on blood

clotting and feedback regulation. • New “Critical Thinking and Clinical Application” question on using

anatomical language to describe the location of a spinal injury and identifying the best medical imaging technique to diagnose a spinal problem.

• Updated “A Closer Look: Medical Imaging” with new discussion and images of mammogram and bone densitometry.

• New “Did You Get It?” questions throughout the chapter.

Chapter 2: Basic Chemistry • New example of atomic symbol and Latin derivative for potassium. • Revised discussion of hydrogen bonds to clarify that electrons are

not involved in this type of bond as they are in covalent and ionic bonds.

• New example of importance of hydrogen bond in holding DNA strands together.

• All references to hydroxyl ion have been corrected to hydroxide ion. • New sports analogies for acids and bases: putting electrons “in the

game,” to represent free protons versus taking electrons “out of the game,” to represent binding a proton so it cannot contribute to a shift in pH.

• New “Did You Get It?” question part on the difference in pH between solutions at pH 11 and pH 5.

• Introduced concepts of hydrophilic and hydrophobic in discussion of phospholipids to help explain the functions of the polar head and fatty acid tails in cell membranes.

• Updated “Did You Get It?” question on lipids to include both phospholipids and cholesterol as cell membrane components.

• New analogy comparing the alpha (α)-helix to a metal spring. • New analogy comparing a beta (β)-sheet to a pleated skirt, or

paper folded into a fan. • New analogy comparing enzymes and substrates to scissors and

paper, respectively. • New description of RNA function as DNA’s “molecular assistant.” • New shorthand symbols for messenger (mRNA), transfer (tRNA)

and ribosomal (rRNA) added. • New analogy comparing glucose and ATP to crude oil and gasoline;

energy must be in the proper form before it can be used by cells. • New explanation of why the terminal phosphate bonds in ATP are

high energy. • New “Critical Thinking and Clinical Application” question on sickle

cell anemia.

Chapter 3: Cells and Tissues • New description of the principle of complementarity. • New information about how mitochondria divide. • New “cargo” in the form of a membrane-bound receptor protein

added to pathway 2 of Figure 3.6. • New analogy for lysosomes as “cellular stomachs.” • New art of plasma membrane and new detail of mitochondrial

function including aerobic respiration in Table 3.1. • New analogy of dust “crowd surfing” on the mucus that cilia carry

from the lungs. • New description of neuron function includes production of

neurotransmitters.

• Updated descriptions of red and yellow bone marrow. • Updated descriptions of sagittal and coronal sutures. • Updated description of the capitulum of the humerus. • New analogy comparing the trochlea meeting the trochlear notch

to a curved “tongue-in-groove” joint. • Updated description of buttock injections to include the

consequences of hitting a nerve. • Updated description of a synovial membrane to include areolar

connective tissue. • Updated description of cartilaginous joints. • New description of saddle joints including a reference to

opposable thumbs. • Updated list of triggers for rheumatoid arthritis. • Discussion of the fetal skull and fontanels moved to the

Developmental Aspects section. • New analogy likening skulls of small children to “bobble heads.” • Updated review question on bones that articulate with the

sphenoid to reflect only bones shown in the figures of Chapter 5. • Updated “Short Answer Essay” question on synovial joints to

include osteoarthritis. • New “Short Answer Essay” question contrasting the foramen

magnum and obturator foramen. • New “Critical Thinking and Clinical Application” question on gouty

arthritis. • New statistics, information, and images added to “A Closer Look:

Joint Ventures.” • Updated description of comminuted fractures on Table 5.2. • Updated Figure 5.6 to include osteoblasts and osteoclasts in the

descriptions of bone addition and resorption, respectively. • Updated Systems In Sync with respect to the descriptions of

relationships of cardiovascular and muscular systems to the skeletal system.

Chapter 6: The Muscular System • Updated descriptions of tendons and aponeuroses. • New analogy about running to explain the difference between the

contraction of skeletal muscle (fast) versus smooth muscle (slow). • Updated description of a sarcomere to include its role as the

structural and functional unit of muscle. • Added discussion of titin to the description of a sarcomere as the

elastic filament that attaches myosin to the Z disc. • New Homeostatic Imbalance on ALS (amyotropic lateral sclerosis,

or Lou Gehrig’s disease). • New “Did You Get It?” question on the roles of calcium in muscle

contraction. • Updated descriptions of cross-bridge formation and the sliding

filament theory, including the role of ATP. • New link to IP Essentials for the sliding filament theory. • New description of flaccid versus spastic paralysis. • New mnemonic device for adduction: “add” back to the body by

moving toward the trunk (midline). • New descriptions of dorsiflexion and plantar flexion with respect

to the head: toes point toward the head or away, respectively. • New girdle analogy for abdominal wall muscles “holding guts in.” • New description of the consequences of an injection being too

close to, or hitting, the sciatic nerve. • New description of tailor’s muscle sitting position. • New description of myasthenia gravis as an autoimmune disease. • New “Short Answer Essay” question about the relationship

between wrist flexors and extensors, including their locations. • New figure question for Figure 6.20 on the origin(s) and

insertion(s) of the rectus femoris depending on the action being performed.

• Updated explanation of steps in Figure 6.5.

Chapter 7: The Nervous System • Updated Figure 7.13 to use superior and inferior instead of

cephalad and caudal. • Updated Figure 7.24 to clarify why there are eight cervical nerves

but only seven cervical vertebrae. • New Learning Outcome on the structures and functions of neurons

and neuroglia.

• Updated description of Nissl body function. • New description clarifying the difference between a synapse and

synaptic cleft. • New analogy for a myelin sheath as the wrapping on an electrical

cord. • New explanation clarifying the differences between myelin sheaths

in the CNS and PNS. • New explanation clarifying the “short circuit” event in multiple

sclerosis means that the signal may stop or “jump” to an unmyelinated neuron.

• New analogy for the structure of a unipolar cell body as a “cul-de- sac” off the “main road” that is the axon.

• Replaced references to the term basal ganglia with the more accurate term basal nuclei.

• Replaced the term arachnoid villi with arachnoid granulations. • New statistics on stroke as the fifth leading cause of death in the

United States (formerly identified as the third leading cause). • New statistics regarding the rate of survival after a stroke. • Replaced the phrase “mentally retarded” in the discussion of

cerebral palsy with “intellectually disabled.” • New information included in “A Closer Look: The ‘Terrible Three’”

reflecting the role of calcium in apoptosis, two new drugs for treatment of Parkinson’s disease, and the variation in dopamine levels in patients with Huntington’s disease.

• New information incorporated in “A Closer Look: Tracking Down CNS Problems” to include a new dopamine imaging technique called DaTscan.

Chapter 8: Special Senses • New description of lacrimal caruncle. • New description of optic disc and the resulting blind spot. • New analogy comparing the ability to see intermediate colors

(between the red, green, and blue cones) to mixing paint. • Updated the description of cataracts. • New example of motion detected by dynamic equilibrium: a

spinning carnival ride. • New analogy for bending of the cupula as divers’ fins in water. • New description of foliate papillae on the side of the tongue,

another location for taste buds. • New art showing the retina in Figure 8.5. • New Figure 8.6 showing the graph of rods and cones, and which

wavelengths of light are detected by each. • Updated Figure 8.12b on maculae. • New “Did You Get It?” questions throughout the chapter.

Chapter 9: The Endocrine System • Updated discussion of the mechanism of hormone action,

including Figure 9.1 and its caption, to reflect that steroid hormones can act via either second messenger or direct gene activation.

• Updated explanation of how hormones alter cell activity. • New analogy comparing second-messenger systems to delivering a

letter. • Revised coverage of endocrine glands to reflect their location in

body from superior to inferior; Table 9.1 has also been revised to reflect the new order.

• Updated description explaining why a goiter forms in the absence of iodine.

• Updated description of body proportions in cretinism. • New “Did You Get It?” question on adrenal cortex hormones.

Chapter 10: Blood • Updated explanation of why the normal temperature of blood is a

bit higher than body temperature. • Added definitions for the suffixes -cytosis and -penia. • Updated the analogy comparing the shape of the eosinophil

nucleus to earmuffs. • Updated the role of monocytes to include activation of

lymphocytes. • Updated the list of locations where red marrow is found in adults. • Updated the major anticoagulants to include warfarin. • New description of petechiae includes comparison to a skin rash.

New to the Twelfth Edition 13

14 New to the Twelfth Edition

• Updated Table 12.1 regarding the role of nasal hairs to include filtration of airborne particles.

• Updated Table 12.3 entry for “Cytokines: Perforin and granzymes” to include natural killer (NK) cells.

• New “Did You Get It?” questions throughout the chapter.

Chapter 13: The Respiratory System • New information explaining neural regulation of breathing with

respect to the dorsal and ventral respiratory groups of the medulla. • New Short Answer Essay question contrasting hyperventilation and

hyperpnea. • Updated “A Closer Look” on cleanliness and asthma. • New “Did You Get It?” questions throughout the chapter.

Chapter 14: The Digestive System • New illustration outlining the parietal and visceral layers of the

peritoneum (Figure 14.5). • New illustrations showing both deciduous and permanent teeth in

greater detail (Figure 14.9). • Updated description of circular folds to provide students with a

visual image of a corkscrew that slows progression of food and increases surface area at the same time.

• Added detail that rennin in infants is the same enzyme used to curdle milk in cheesemaking.

• Added narcotic pain medications to the list of causes of constipation, with stool softeners as a method of treatment.

• New “Did You Get It?” question on the four types of teeth and their functions.

• Added brief discussion of nucleic acid digestion, including the source of the enzymes and the reminder that nucleotides are the building blocks.

• Revised “A Closer Look” box on obesity to update references, statistics, and methods used to determine body composition, such as DEXA, the Bod Pod, and underwater weighing.

Chapter 15: The Urinary System • Updated descriptions of the arterioles that connect to the

glomerulus. • Included a new learning tool describing the internal urethral

sphincter as involuntary. • New “Short Answer Essay” question contrasting the homeostatic

imbalances oliguria, anuria, polyuria, and nocturia. • New “Critical Thinking and Clinical Application” question about

the relationship between hypertension and impaired kidney function, and tests that are used for determining impaired kidney function.

• New information included in “A Closer Look: Renal Failure and the Artificial Kidney” about a blood test to determine the creatinine level in order to estimate the rate of glomerular filtration.

• Did You Get It?

Chapter 16: The Reproductive System • New explanation of the purpose of polar bodies: to reduce the

chromosome number during oogenesis. • Update of suggested age range for women to begin having regular

mammograms: between 45 and 54. • New Concept Link on chemotaxis. • New photomicrograph showing sperm swarming an oocyte in

Figure 16.16. • New explanation of how an egg blocks additional sperm from

entering; the surface sperm receptors on an oocyte are shed after the first sperm enters the cell.

• New clarification with updated definitions of miscarriage and abortion.

• Added a learning tool about blood type reminding readers that a person does not make antibodies against their own blood type antigen(s).

• Updated discussion of lack of vitamin B12 as the cause of pernicious anemia and how this relates to intrinsic factor.

Chapter 11: The Cardiovascular System • Updated description of pericardium. • Revised discussion of the function of the atria to clarify that they

assist with ventricular filling. • Arteries and veins are now introduced in terms of the direction of

blood flow with respect to the heart. • New analogy comparing valve cusps filling with blood to a

parachute filling with air. • New analogy comparing the intrinsic conduction system setting

heart rhythm to a drummer setting the beat for a rock band playing a song.

• New discussion of AEDs (automatic external defibrillators) included in the discussion of fibrillation.

• Reorganized section on the cardiac cycle to include five stages. • New “Did You Get It?” question about isovolumetric contraction. • Updated description of the effect of congestive heart failure on

stroke volume. • Updated description of pulmonary congestion. • Updated description of pulmonary embolism. • Discussion of fetal circulation moved to the Developmental

Aspects section. • Updated description of the blood pressure gradient to include a

pressure of zero in the right atrium. • New layout of Figure 11.8 reflecting five stages of the cardiac cycle. • Updated Figure 11.9 description to clarify that any change in heart

rate or stroke volume will also cause a change in cardiac output. • Updated description of Figures 11.13 and 11.14 to include a

statement that all vessels are bilateral unless otherwise stated in the text.

• Updated “A Closer Look” box on atherosclerosis.

Chapter 12: The Lymphatic System and Body Defenses • Updated Figure 12.10 on lysis by complement to reflect water

flowing into the cell to cause lysis. • Added the role of B cells in antigen presentation to Figure 12.19. • New information added regarding discovery of lymphatics in the

central nervous system. • Updated the description of adaptive defenses as defenses that fight

antigens that get past the innate defenses. • New description of how natural killer cells kill: via perforin and

granzymes. • Updated the description of positive chemotaxis to include

movement toward the stimulus. • Revised description of interferon to clarify that interferon fights

only viral pathogens, not bacteria or fungi. • New antibody function has been listed: opsonization. • New description of Graves’ disease explaining that excess

production of thyroxine is in response to antibodies that mimic TSH (thyroid-stimulating hormone).

• New descriptions of two additional types of hypersensitivities: reactions resulting in cell lysis and those forming antigen-antibody complexes.

• New example of when epinephrine is used during acute hypersensitivity: EpiPen® injection.

• New Short Answer Essay question provided on mechanisms of killing used by the immune system, including lysozyme, perforin, and granzymes, and membrane attack complex (MAC).

• Updated “A Closer Look” box on AIDS, including new title.

15

Acknowledgments

University; Amy Goode, Illinois Central College; Jeannette Hafey, Springfield College; Ashley Hagler, Gaston College; Frances Miles, Lake Michigan College–Napier Avenue Campus; Margaret Ott, Tyler Junior College; Heidi Peterson, Indian Hills Commu- nity College–Ottumwa Campus; Laura Ritt, Burling- ton County College; Holly Sanders, Gwinnett Technical College; Leba Sarkis, Aims Community College; Gustavo A. Solis, Forsyth Technical Com- munity College; Ginny Stokes, Nash Community College; Robert Suddith, Cape Fear Community Col- lege; John F. Tarpey, City College of San Francisco; Deborah S. Temperly, Delta College; Claudia Wil- liams, Campbell University.

The entire group from Pearson and beyond deserves our heartfelt thanks for being the best team around! They have provided support, guid- ance, and humor throughout the writing process, which made the process fun and was most appre- ciated. Special thanks to Serina Beauparlant, Edi- tor-In-Chief, Brooke Suchomel, Sr. Acquisitions Editor, and Tiffany Mok, Program Manager who passed the reins to Lauren Harp, Sr. Portfolio Man- ager, for crossing the finish line. Thanks also to Nicky Montalvo, Editorial Coordinator. Thank you to the content development team—Suzanne Olivier, Alice Fugate, and Laura Southworth—for their attention to detail and collaborative minds. Thank you Patrice Fabel, Ziki Dekel, and Lauren Hill for supervising an impressive variety of media content that will benefit both students and instructors. A special thank-you to Gary Hespenheide for the book’s beautiful and creative new interior and cover designs. The work of Kristin Piljay, Photo Researcher, resulted in some striking new photos for this edition; and Sally Peyrefitte, our excellent and diligent copyeditor, ensured a consistent style throughout the book. Proofreader Betsy Dietrich skillfully reviewed every page proof, and Sallie Steele provided a thorough and accurate index. Our talented art house, Imagineering STA Media Services, Inc., and compositor, Aptara, worked tire- lessly to provide stunning artwork and student- friendly page layouts. Stacey Weinberger, Senior Manufacturing Buyer, Allison Rona, and Derek

Many people contributed to our efforts in the cre- ation of this twelfth edition. We offer our profound thanks to the following reviewers, whose thought- ful critiques informed and enhanced our develop- ment of this edition:

• William Brazelle, University of South Florida

• Sheree Daniel, Trinity Valley Community College

• Trevor Day, Mount Royal University

• Camille Di Scala, Chandler-Gilbert Community College

• Pamela Boyter Jackson, Piedmont Technical College

• Roop Jayaraman, Central Michigan University

• Kimberly Kushner, Pueblo Community College

• Frances Mills, Lake Michigan College

• Diane Pelletier, Green River Community College

• Heidi Peterson, Indian Hills Community College

• Kenneth Ryan, Alexandria Technical and Community College

• Holly Sanders, Gwinnett Technical College

• Scott Schaeffer, Harford Community College

• I-Chia Shih, Leeward Community College, University of Hawaii

• K. Dale Smoak, Piedmont Technical College

• Bill Snyder, Bluegrass Community and Technical College

• Greg Tefft, Northwest State Community College

• Sandra Uyeshiro, Modesto Junior College

• Khursheed Wankadiya, Central Piedmont Community College

• Carol T. Wismer, College of Lake County

Thanks are also extended to the reviewers of the Eleventh Edition: Carmen Carpenter, South Univer- sity; Steven D. Collins, Niagara College; Janie Cor- bitt, Central Georgia Technical College–Milledgeville Campus; Eric D. Forman, Sauk Valley Community College; Andrew Goliszek, North Carolina A&T State

16 Acknowledgments

Perrigo deserve special thanks for their expertise in delivering and presenting the final product to the market. A special thank you goes to David Novak, our Production and Art Coordinator, for taking on the role of two people during this edition and flaw- lessly handling every text and art-related production

detail—David made the whole process smooth and successful. And last, but not least, Michele Mangelli—a tremendous thank-you for your skillful oversight of all aspects of the 12th edition, includ- ing assisting a first-time co-author in all things pub- lishing . . . you’re an unflappable rock star!

Suzanne M. Keller

Anatomy and Physiology Pearson Education 1301 Sansome Street San Francisco, CA 94111

Elaine N. Marieb

The publishers would like to thank the following for their contribution to the Global Edition:

Contributor

Christiane Van den Branden, Vrije Universiteit Brussel

Reviewers

Hemant Kumar, MBBS Snezana Kusljic, The University of Melbourne Eva Strandell, Halmstad University

17

1 The Human Body: An Orientation 27 An Overview of Anatomy and Physiology 27

Anatomy 27

Physiology 28

Relationship between Anatomy and Physiology 28

Levels of Structural Organization 28 From Atoms to Organisms 28

Organ System Overview 29 Integumentary System • Skeletal System • Muscular System • Nervous System • Endocrine System • Cardiovascular System • Lymphatic System • Respiratory System • Digestive System • Urinary System • Reproductive System

Maintaining Life 33 Necessary Life Functions 33

Maintaining Boundaries • Movement • Responsiveness • Digestion • Metabolism • Excretion • Reproduction • Growth

Survival Needs 35

The Language of Anatomy 38 Anatomical Position 38

Directional Terms 38

Regional Terms 38 Anterior Body Landmarks • Posterior Body Landmarks

Body Planes and Sections 41

Body Cavities 41 Dorsal Body Cavity • Ventral Body Cavity • Other Body Cavities

Homeostasis 45 Components of Homeostatic Control Systems 45

Feedback Mechanisms 45

SUMMARy 47

REviEw QUESTiONS 48

CRiTiCAL THiNkiNg AND CLiNiCAL APPLiCATiON QUESTiONS 49

A CLOSER LOOk Medical Imaging: Illuminating the Body 36

2 Basic Chemistry 50 Concepts of Matter and Energy 50

Matter 50

Energy 51 Forms of Energy • Energy Form Conversions

Composition of Matter 52 Elements and Atoms 52

Atomic Structure 52 The Basic Atomic Subparticles • Planetary and Orbital Models of an Atom

Identifying Elements 54 Atomic Number • Atomic Mass Number • Atomic Weight and Isotopes

Molecules and Compounds 57

Chemical Bonds and Chemical Reactions 58

Bond Formation 58 Role of Electrons • Types of Chemical Bonds

Patterns of Chemical Reactions 62 Synthesis Reactions • Decomposition Reactions • Exchange Reactions • Factors Influencing the Rate of Chemical Reactions

Biochemistry: The Chemical Composition of Living Matter 64

Inorganic Compounds 65 Water • Salts • Acids and Bases

Contents

Organic Compounds 68 Carbohydrates • Lipids • Proteins • Nucleic Acids • Adenosine Triphosphate (ATP)

SUMMARy 83

REviEw QUESTiONS 85

CRiTiCAL THiNkiNg AND CLiNiCAL APPLiCATiON QUESTiONS 87

FOCUS ON CAREERS Pharmacy Technician 82

3 Cells and Tissues 88 PART i: CELLS 88

Overview of the Cellular Basis of Life  88

Anatomy of a generalized Cell 89 The Nucleus 89

Nuclear Envelope • Nucleolus • Chromatin

The Plasma Membrane 90 The Fluid Mosaic Model • Cell Membrane Junctions

The Cytoplasm 93 Cytosol and Inclusions • Organelles

Cell Extensions 97 Cilia and Flagella • Microvilli

Cell Diversity 100

Cell Physiology 102 Membrane Transport 102

Passive Processes: Diffusion and Filtration • Active Processes

Cell Division 108 Preparations: DNA Replication • Events of Cell Division

Protein Synthesis 111 Genes: The Blueprint for Protein Structure • The Role of RNA • The Process of Protein Synthesis

PART ii: BODy TiSSUES 114

Epithelial Tissue 114 Hallmarks of Epithelium 114

Classification of Epithelia 115 Simple Epithelia • Stratified Epithelia • Glandular Epithelium

Connective Tissue 119 Hallmarks of Connective Tissue 119

Extracellular Matrix 120

Types of Connective Tissue 120 Bone • Cartilage • Dense Connective Tissue • Loose Connective Tissue • Blood

Muscle Tissue 124 Skeletal Muscle 124

Cardiac Muscle 124

Smooth Muscle 126

Nervous Tissue 126

Tissue Repair (wound Healing) 126

PART iii: DEvELOPMENTAL ASPECTS OF CELLS AND TiSSUES 128

SUMMARy 130

REviEw QUESTiONS 133

CRiTiCAL THiNkiNg AND CLiNiCAL APPLiCATiON QUESTiONS 134

A CLOSER LOOk IV Therapy and Cellular “Tonics” 105

A CLOSER LOOk Cancer—An Intimate Enemy 130

4 Skin and Body Membranes 135 Classification of Body Membranes 135

Epithelial Membranes 136 Cutaneous Membrane • Mucous Membranes • Serous Membranes

Connective Tissue Membranes 136

Chapter 2, continued

18 Contents

Cervical Vertebrae • Thoracic Vertebrae • Lumbar Vertebrae • Sacrum • Coccyx

Thoracic Cage 182 Sternum • Ribs

Appendicular Skeleton 184 Bones of the Shoulder Girdle 184

Bones of the Upper Limbs 184 Arm • Forearm • Hand

Bones of the Pelvic Girdle 188

Bones of the Lower Limbs 190 Thigh • Leg • Foot

Joints 192 Fibrous Joints 195

Cartilaginous Joints 195

Synovial Joints 195

Types of Synovial Joints Based on Shape 196

Developmental Aspects of the Skeleton 199

Birth to Adulthood 199

Older Adults 201

SUMMARy 203

REviEw QUESTiONS 204

CRiTiCAL THiNkiNg AND CLiNiCAL APPLiCATiON QUESTiONS 206

FOCUS ON CAREERS Radiologic Technologist 169

A CLOSER LOOk Joint Ventures 192

SySTEMS iN SyNC 202

6 The Muscular System 207 Overview of Muscle Tissues 207

Muscle Types 207 Skeletal Muscle • Smooth Muscle • Cardiac Muscle

Muscle Functions 211 Produce Movement • Maintain Posture and Body Position • Stabilize Joints • Generate Heat • Additional Functions

The integumentary System (Skin) 138 Functions of the Integumentary System 138

Structure of the Skin 139 Epidermis • Dermis

Skin Color 144

Appendages of the Skin 145 Cutaneous Glands • Hair and Hair Follicles • Nails

Homeostatic Imbalances of Skin 149 Infections and Allergies • Burns • Skin Cancer

Developmental Aspects of Skin and Body Membranes 153

SUMMARy 156

REviEw QUESTiONS 157

CRiTiCAL THiNkiNg AND CLiNiCAL APPLiCATiON QUESTiONS 158

A CLOSER LOOk A Wrinkle Out of Time 143

FOCUS ON CAREERS Medical Transcriptionist 154

SySTEMS iN SyNC 155

5 The Skeletal System 160 Bones: An Overview 160

Functions of the Bones 161

Classification of Bones 161

Structure of Bone 163 Gross Anatomy of a Long Bone • Microscopic Anatomy

Bone Formation, Growth, and Remodeling 167

Bone Formation and Growth • Bone Remodeling

Bone Fractures 170

Axial Skeleton 172 Skull 172

Cranium • Facial Bones • The Hyoid Bone

Vertebral Column (Spine) 178

Contents 19

Chapter 6, continued A CLOSER LOOk Anabolic Steroids: Dying to Win? 231

SySTEMS iN SyNC 246

7 The Nervous System 251 Organization of the Nervous System 252

Structural Classification 253

Functional Classification 253

Nervous Tissue: Structure and Function 253

Supporting Cells 253

Neurons 255 Anatomy • Classification • Physiology: Nerve Impulses • Physiology: Reflexes

Central Nervous System 265 Functional Anatomy of the Brain 265

Cerebral Hemispheres • Diencephalon • Brain Stem • Cerebellum

Protection of the Central Nervous System 273 Meninges • Cerebrospinal Fluid • The Blood-Brain Barrier

Brain Dysfunctions 277

Spinal Cord 278 Gray Matter of the Spinal Cord and Spinal Roots • White Matter of the Spinal Cord

Peripheral Nervous System 281 Structure of a Nerve 281

Cranial Nerves 283

Spinal Nerves and Nerve Plexuses 283

Autonomic Nervous System 290 Somatic and Autonomic Nervous Systems Compared • Anatomy of the Parasympathetic Division • Anatomy of the Sympathetic Division • Autonomic Functioning

Developmental Aspects of the Nervous System 295

SUMMARy 299

Microscopic Anatomy of Skeletal Muscle 211

Skeletal Muscle Activity 213 Stimulation and Contraction of Single Skeletal Muscle Fibers 213

The Nerve Stimulus and the Action Potential • Mechanism of Muscle Contraction: The Sliding Filament Theory

Contraction of a Skeletal Muscle as a Whole 217

Graded Responses • Providing Energy for Muscle Contraction • Muscle Fatigue and Oxygen Deficit • Types of Muscle Contractions—Isotonic and Isometric • Muscle Tone • Effect of Exercise on Muscles

Muscle Movements, Roles, and Names 222

Types of Body Movements 222 Special Movements

Interactions of Skeletal Muscles in the Body 226

Naming Skeletal Muscles 228

Arrangement of Fascicles 228

gross Anatomy of Skeletal Muscles 229

Head and Neck Muscles 229 Facial Muscles • Neck Muscles

Trunk Muscles 232 Anterior Muscles • Posterior Muscles

Muscles of the Upper Limb 235 Muscles Causing Movement at the Elbow Joint

Muscles of the Lower Limb 235 Muscles Causing Movement at the Hip Joint • Muscles Causing Movement at the Knee Joint • Muscles Causing Movement at the Ankle and Foot

Developmental Aspects of the Muscular System 244

SUMMARy 245

REviEw QUESTiONS 248

CRiTiCAL THiNkiNg AND CLiNiCAL APPLiCATiON QUESTiONS 249

20 Contents

PART iii: CHEMiCAL SENSES: SMELL AND TASTE 324

Olfactory Receptors and the Sense of Smell  324

Taste Buds and the Sense of Taste 326

PART iv: DEvELOPMENTAL ASPECTS OF THE SPECiAL SENSES 327 SUMMARy 329

REviEw QUESTiONS 331

CRiTiCAL THiNkiNg AND CLiNiCAL APPLiCATiON QUESTiONS 332

A CLOSER LOOk Visual Pigments—The Actual Photoreceptors 311

A CLOSER LOOk Bringing Things into Focus 315

FOCUS ON CAREERS Physical Therapy Assistant 321

9 The Endocrine System 334 The Endocrine System and Hormone Function—An Overview 335

The Chemistry of Hormones 335

Hormone Action 335 Direct Gene Activation • Second-Messenger System

Stimuli for Control of Hormone Release 337

Hormonal Stimuli • Humoral Stimuli • Neural Stimuli

The Major Endocrine Organs 338 Pituitary Gland and Hypothalamus 339

Pituitary-Hypothalamus Relationships

Pineal Gland 343

Thyroid Gland 343

Parathyroid Glands 345

Thymus 346

REviEw QUESTiONS 301

CRiTiCAL THiNkiNg AND CLiNiCAL APPLiCATiON QUESTiONS 303

A CLOSER LOOk The “Terrible Three” 278

A CLOSER LOOk Tracking Down CNS Problems 296

SySTEMS iN SyNC 298

8 Special Senses 304 PART i: THE EyE AND viSiON 305

Anatomy of the Eye 305 External and Accessory Structures 305

Internal Structures: The Eyeball 307 Layers Forming the Wall of the Eyeball • Lens

Physiology of vision 313 Pathway of Light through the Eye and Light Refraction 313

Visual Fields and Visual Pathways to the Brain 314

Eye Reflexes 316

PART ii: THE EAR: HEARiNg AND BALANCE 316

Anatomy of the Ear 317 External (Outer) Ear 317

Middle Ear 318

Internal (Inner) Ear 318

Equilibrium 318 Static Equilibrium 319

Dynamic Equilibrium 319

Hearing 322

Hearing and Equilibrium Deficits 323

Contents 21

Chapter 9, continued Developmental Aspects of Blood 378

SUMMARy 379

REviEw QUESTiONS 380

CRiTiCAL THiNkiNg AND CLiNiCAL APPLiCATiON QUESTiONS 381

FOCUS ON CAREERS Phlebotomy Technician 376

11 The Cardiovascular System 382 The Heart 383

Anatomy of the Heart 383 Size, Location, and Orientation • Coverings and Walls of the Heart

Chambers and Associated Great Vessels 384

Heart Valves 387 Cardiac Circulation

Physiology of the Heart 390 Intrinsic Conduction System of the Heart: Setting the Basic Rhythm • Cardiac Cycle and Heart Sounds • Cardiac Output

Blood vessels 396 Microscopic Anatomy of Blood Vessels 396

Tunics • Structural Differences in Arteries, Veins, and Capillaries

Gross Anatomy of Blood Vessels 399 Major Arteries of the Systemic Circulation • Major Veins of the Systemic Circulation • Special Circulations

Physiology of Circulation 406 Arterial Pulse • Blood Pressure • Capillary Exchange of Gases and Nutrients • Fluid Movements at Capillary Beds

Developmental Aspects of the Cardiovascular System 415

SUMMARy 418

REviEw QUESTiONS 420

CRiTiCAL THiNkiNg AND CLiNiCAL APPLiCATiON QUESTiONS 422

A CLOSER LOOk Electrocardiography: (Don’t) Be Still My Heart 393

Adrenal Glands 346 Hormones of the Adrenal Cortex • Hormones of the Adrenal Medulla

Pancreatic Islets 349

Gonads 353 Hormones of the Ovaries • Hormones of the Testes

Other Hormone-Producing Tissues and Organs 353

Developmental Aspects of the Endocrine System 357

SUMMARy 359

REviEw QUESTiONS 361

CRiTiCAL THiNkiNg AND CLiNiCAL APPLiCATiON QUESTiONS 362

A CLOSER LOOk Potential Uses for Growth Hormone 342

SySTEMS iN SyNC 358

10 Blood 363 Composition and Functions of Blood  363

Components 364

Physical Characteristics and Volume 364

Plasma 364

Formed Elements 366 Erythrocytes • Leukocytes • Platelets

Hematopoiesis (Blood Cell Formation) 371 Formation of Red Blood Cells • Formation of White Blood Cells and Platelets

Hemostasis 373 Phases of Hemostasis 373

Disorders of Hemostasis 374

Blood groups and Transfusions 375 Human Blood Groups 375

Blood Typing 378

22 Contents

SUMMARy 457

REviEw QUESTiONS 459

CRiTiCAL THiNkiNg AND CLiNiCAL APPLiCATiON QUESTiONS 461

A CLOSER LOOk AIDS: An Ongoing Pandemic 454

SySTEMS iN SyNC 456

13 The Respiratory System 462 Functional Anatomy of the Respiratory System 462

The Nose 463

The Pharynx 464

The Larynx 465

The Trachea 466

The Main Bronchi 466

The Lungs 467 The Bronchial Tree • Respiratory Zone Structures and the Respiratory Membrane

Respiratory Physiology 471 Mechanics of Breathing 471

Inspiration • Expiration

Respiratory Volumes and Capacities 474

Nonrespiratory Air Movements 475

Respiratory Sounds 475

External Respiration, Gas Transport, and Internal Respiration 475

External Respiration • Gas Transport in the Blood • Internal Respiration

Control of Respiration 478 Neural Regulation: Setting the Basic Rhythm • Nonneural Factors Influencing Respiratory Rate and Depth

Respiratory Disorders 480

Developmental Aspects of the Respiratory System 483

SUMMARy 485

A CLOSER LOOk Atherosclerosis? Get Out the Cardiovascular Drāno! 412

SySTEMS iN SyNC 417

12 The Lymphatic System and Body Defenses 424

PART i: THE LyMPHATiC SySTEM 424

Lymphatic vessels 425

Lymph Nodes 426

Other Lymphoid Organs 428

PART ii: BODy DEFENSES 429

innate Body Defenses 430 Surface Membrane Barriers 430

Internal Defenses: Cells and Chemicals 432 Natural Killer Cells • Inflammatory Response • Phagocytes • Antimicrobial Proteins • Fever

Adaptive Body Defenses 436 Antigens 438

Cells of the Adaptive Defense System: An Overview 438

Lymphocytes • Antigen-Presenting Cells

Humoral (Antibody-Mediated) Immune Response 441

Active and Passive Humoral Immunity • Antibodies

Cellular (Cell-Mediated) Immune Response 446

Organ Transplants and Rejection 448

Disorders of Immunity 451

PART iii: DEvELOPMENTAL ASPECTS OF THE LyMPHATiC SySTEM AND BODy DEFENSES 455

Contents 23

Chapter 13, continued PART ii: NUTRiTiON AND METABOLiSM 513

Nutrition 513 Dietary Recommendations 513

Dietary Sources of the Major Nutrients 514 Carbohydrates • Lipids • Proteins • Vitamins • Minerals

Metabolism 516 Carbohydrate, Fat, and Protein Metabolism in Body Cells 516

Carbohydrate Metabolism • Fat Metabolism • Protein Metabolism

The Central Role of the Liver in Metabolism 520

General Metabolic Functions • Cholesterol Metabolism and Transport

Body Energy Balance 523 Regulation of Food Intake • Metabolic Rate and Body Heat Production • Body Temperature Regulation

PART iii: DEvELOPMENTAL ASPECTS OF THE DigESTivE SySTEM AND METABOLiSM 527 SUMMARy 532

REviEw QUESTiONS 534

CRiTiCAL THiNkiNg AND CLiNiCAL APPLiCATiON QUESTiONS 536

A CLOSER LOOk Peptic Ulcers: “Something Is Eating at Me” 512

A CLOSER LOOk Obesity: Magical Solution Wanted 529

SySTEMS iN SyNC 531

15 The Urinary System 537 kidneys 538

Location and Structure 538 Kidney Structure • Blood Supply

Nephrons 539

REviEw QUESTiONS 487

CRiTiCAL THiNkiNg AND CLiNiCAL APPLiCATiON QUESTiONS 488

A CLOSER LOOk Too Clean for Our Own Good? 482

SySTEMS iN SyNC 484

14 The Digestive System and Body Metabolism 489

PART i: ANATOMy AND PHySiOLOgy OF THE DigESTivE SySTEM 489

Anatomy of the Digestive System 489

Organs of the Alimentary Canal 490 Mouth • Pharynx • Esophagus • Stomach • Small Intestine • Large Intestine

Accessory Digestive Organs 500 Teeth • Salivary Glands • Pancreas • Liver and Gallbladder

Functions of the Digestive System 502

Overview of Gastrointestinal Processes and Controls 503

Activities Occurring in the Mouth, Pharynx, and Esophagus 506

Food Ingestion and Breakdown • Food Propulsion— Swallowing and Peristalsis

Activities of the Stomach 507 Food Breakdown • Food Propulsion

Activities of the Small Intestine 509 Chyme Breakdown and Absorption • Chyme Propulsion

Activities of the Large Intestine 511 Nutrient Breakdown and Absorption • Propulsion of Food Residue and Defecation

24 Contents

Epididymis • Ductus Deferens • Urethra

Accessory Glands and Semen 567 Seminal Vesicles • Prostate • Bulbo-urethral Glands • Semen

External Genitalia 568

Male Reproductive Functions 569 Spermatogenesis 569

Testosterone Production 571

Anatomy of the Female Reproductive System 573

Ovaries 573

Duct System 573 Uterine Tubes • Uterus • Vagina

External Genitalia and Female Perineum 576

Female Reproductive Functions and Cycles 577

Oogenesis and the Ovarian Cycle 577

Hormone Production by the Ovaries 579

Uterine (Menstrual) Cycle 580

Mammary glands 580

Pregnancy and Embryonic Development 583

Accomplishing Fertilization 584

Events of Embryonic and Fetal Development 585

Effects of Pregnancy on the Mother 589 Anatomical Changes • Physiological Changes

Childbirth 591 Initiation of Labor • Stages of Labor

Developmental Aspects of the Reproductive System 593

SUMMARy 598

REviEw QUESTiONS 600

CRiTiCAL THiNkiNg AND CLiNiCAL APPLiCATiON QUESTiONS 602

A CLOSER LOOk Contraception: Preventing Pregnancy 594

SySTEMS iN SyNC 597

Urine Formation and Characteristics 542 Glomerular Filtration • Tubular Reabsorption • Tubular Secretion • Nitrogenous Wastes • Characteristics of Urine

Ureters, Urinary Bladder, and Urethra  546

Ureters 546

Urinary Bladder 547

Urethra 548

Micturition 548

Fluid, Electrolyte, and Acid-Base Balance 550

Maintaining Water Balance of Blood 550 Body Fluids and Fluid Compartments • The Link between Water and Electrolytes • Regulation of Water Intake and Output

Maintaining Electrolyte Balance 553

Maintaining Acid-Base Balance of Blood 555 Blood Buffers • Respiratory Mechanisms • Renal Mechanisms

Developmental Aspects of the Urinary System 557

SUMMARy 561

REviEw QUESTiONS 562

CRiTiCAL THiNkiNg AND CLiNiCAL APPLiCATiON QUESTiONS 563

A CLOSER LOOk Renal Failure and the Artificial Kidney 549

FOCUS ON CAREERS Licensed Practical Nurse (LPN) 558

SySTEMS iN SyNC 560

16 The Reproductive System 564 Anatomy of the Male Reproductive System 565

Testes 565

Duct System 565

Contents 25

Appendix D Key Information about Vitamins and Many Essential Minerals 613

Glossary 617

Credits 630

Subject Index 631

Appendixes Appendix A: Answers to Did You Get It?

Questions and Multiple Choice Review Questions 603

Appendix B: Word Roots, Prefixes, and Suffixes 610

Appendix C: Periodic Table of the Elements 612

26 Contents

27

1

the seeds. Adults become upset when their hearts pound, when they have uncontrollable hot flashes, or when they cannot keep their weight down.

Anatomy and physiology, subdivisions of biol- ogy, explore many of these topics as they describe how our bodies are put together and how they work.

Anatomy Anatomy (ah-nat′o-me) is the study of the structure and shape of the body and its parts and their rela- tionships to one another. Whenever we look at our own body or study large body structures such as the heart or bones, we are observing gross anatomy;

An Overview of Anatomy and Physiology ➔ Learning Objectives

□□ Define anatomy and physiology.

□□ Explain how anatomy and physiology are related.

Most of us are naturally curious about our bodies; we want to know what makes us tick. Infants can keep themselves happy for a long time staring at their own hands or pulling their mother’s nose. Older children wonder where food goes when they swallow it, and some believe that they will grow a watermelon in their belly if they swallow

The Human Body: An Orientation

WHAT

HOW

WHY

Anatomy is the study of the structure, or

physical form, of the body.

The function, or physiology, of each body

part and the body as a whole is dependent on the anatomy of

those parts; in other words, structure determines

function.

This text will help you learn structures and functions

so you can understand the role of individual organs and body

systems and how they interact to support life.

InsTrucTOrs

New Building Vocabulary coaching Activities for this chapter are assignable in

28 Essentials of Human Anatomy and Physiology

Levels of structural Organization ➔ Learning Objectives

□□ name the six levels of structural organization that make up the human body, and explain how they are related.

□□ name the organ systems of the body, and briefly state the major functions of each system.

□□ Identify and classify by organ system all organs discussed.

From Atoms to Organisms The human body exhibits many levels of structural complexity (Figure 1.1). The simplest level of the structural ladder is the chemical level (covered in Chapter 2). At this level, atoms, tiny building blocks of matter, combine to form molecules such as water, sugar, and proteins, like those that make up our muscles. Molecules, in turn, associate in specific ways to form microscopic cells, the small- est units of all living things. (We will examine the cellular level in Chapter 3.) All cells have some common structures and functions, but individual cells vary widely in size, shape, and their particu- lar roles in the body.

The simplest living creatures are composed of single cells, but in complex organisms such as trees or human beings, the structural ladder con- tinues on to the tissue level. Tissues consist of groups of similar cells that have a common func- tion. There are four basic tissue types, and each plays a definite but different role in the body. (We discuss tissues in Chapter 3.)

An organ is a structure composed of two or more tissue types that performs a specific function for the body. At the organ level of organization, extremely complex functions become possible. For example, the small intestine, which digests and absorbs food, is composed of all four tissue types. An organ system is a group of organs that work together to accomplish a common purpose. For example, the heart and blood vessels of the cardiovascular system circulate blood continuously to carry nutrients and oxygen to all body cells.

In all, 11 organ systems make up the living human being, or the organism, which represents the highest level of structural organization, the organismal level. The organismal level is the sum total of all structural levels working together to keep us alive. The major organs of each system

that is, we are studying large, easily observable structures. Indeed, the term anatomy, derived from the Greek words meaning to cut (tomy) apart (ana), is related most closely to gross anatomical studies because in such studies, preserved animals or their organs are dissected (cut up) to be exam- ined. Microscopic anatomy, in contrast, is the study of body structures that are too small to be seen with the naked eye. The cells and tissues of the body can only be seen through a microscope.

Physiology Physiology (fiz″e-ol′o-je) is the study of how the body and its parts work or function ( physio = nature; ology = the study of). Like anatomy, physi- ology has many subdivisions. For example, neu- rophysiology explains the workings of the nervous system, and cardiac physiology studies the func- tion of the heart.

relationship between Anatomy and Physiology Anatomy and physiology are always inseparable. The parts of your body form a well-organized unit, and each of those parts has a job to do to make the body operate as a whole. Structure determines what functions can take place. For example, the lungs are not muscular chambers like the heart and so cannot pump blood through the body, but because the walls of their air sacs are very thin, they can exchange gases and provide oxygen to the body. We stress the intimate relationship between anatomy and physiology throughout this text to make your learning meaningful.

Did You Get It? 1. Why would you have a hard time learning and

understanding physiology if you did not also understand anatomy?

2. Kidney function, bone growth, and beating of the heart are all topics of anatomy. True or false?

For answers, see Appendix A.

➔ConCeptLinkThroughout this text, Concept Links will highlight links between concepts and/or organ systems. Keep in mind that although discussions of the systems are separated into chapters for detailed study, the overall goal of this text is for you not only to gain an understanding of each individual system, but also to learn how the body systems interact to sustain life. ➔

Chapter 1: The Human Body: An Orientation 29

1

waterproofs the body and cushions and protects the deeper tissues from injury. With the help of sunlight, it produces vitamin D. It also excretes salts in perspiration and helps regulate body tem- perature. Sensory receptors located in the skin alert us to what is happening at the body surface.

skeletal system

The skeletal system consists of bones, cartilages, and joints (Figure 1.2b). It supports the body and

are shown in Figure 1.2 on pp. 31–32. Refer to the figure as you read through the following descrip- tions of the organ systems.

Organ system Overview Integumentary system

The integumentary (in-teg″u-men′tar-e) system is the external covering of the body, or the skin, including the hair and fingernails (Figure 1.2a). It

Molecules

Atoms

Smooth muscle tissue

Epithelial tissue

Blood vessels

Heart

Smooth muscle tissue

Connective tissue

Blood vessel (organ)

Cardio– vascular system

1

3

4

5 6

Chemical level Atoms combine to form molecules.

Smooth muscle cell

2 Cellular level Cells are made up of molecules.

Tissue level Tissues consist of similar types of cells.

Organ level Organs are made up of different types of tissues.Organ system level

Organ systems consist of different organs that work together closely.

Organismal level Human organisms are made up of many organ systems.

Figure 1.1 Levels of structural organization. In this diagram, components of the cardiovascular system are used to illustrate the levels of structural organization in a human being.

30 Essentials of Human Anatomy and Physiology

provides a framework that the skeletal muscles use to cause movement. It also has protective func- tions (for example, the skull encloses and protects the brain), and the cavities of the skeleton are the sites where blood cells are formed. The hard sub- stance of bones acts as a storehouse for minerals.

Muscular system

The muscles of the body have only one function— to contract, or shorten. When this happens, move- ment occurs. The mobility of the body as a whole reflects the activity of skeletal muscles, the large, fleshy muscles attached to bones (Figure 1.2c). When these contract, you are able to stand erect, walk, jump, grasp, throw a ball, or smile. The skel- etal muscles form the muscular system. These muscles are distinct from the muscles of the heart and of other hollow organs, which move fluids (such as blood or urine) or other substances (such as food) along definite pathways within the body.

nervous system

The nervous system is the body’s fast-acting con- trol system. It consists of the brain, spinal cord, nerves, and sensory receptors (Figure 1.2d). The body must be able to respond to stimuli com- ing from outside the body (such as light, sound, or changes in temperature) and from inside the body (such as decreases in oxygen or stretching of tissue). The sensory receptors detect changes in temperature, pressure, or light, and send messages (via electrical signals called nerve impulses) to the central nervous system (brain and spinal cord) so that it is constantly informed about what is going on. The central nervous system then assesses this information and responds by activating the appro- priate body effectors (muscles or glands, which are organs that produce secretions).

Endocrine system

Like the nervous system, the endocrine (en′do-krin) system controls body activities, but it acts much more slowly. Endocrine glands produce chemi- cal molecules called hormones and release them into the blood to travel to relatively distant target organs.

The endocrine glands include the pituitary, thyroid, parathyroids, adrenals, thymus, pancreas, pineal, ovaries (in the female), and testes (in the male) (Figure 1.2e). The endocrine glands are not connected anatomically in the same way that the parts of other organ systems are. What they have

in common is that they all secrete hormones, which regulate other structures. The body func- tions controlled by hormones are many and var- ied, involving every cell in the body. Growth, reproduction, and the use of nutrients by cells are all controlled (at least in part) by hormones.

cardiovascular system

The primary organs of the cardiovascular sys- tem are the heart and blood vessels (Figure 1.2f). Using blood as a carrier, the cardiovascular system delivers oxygen, nutrients, hormones, and other substances to, and picks up wastes such as carbon dioxide from, cells near sites of exchange. White blood cells and chemicals in the blood help to protect the body from such foreign invaders as bacteria, viruses, and tumor cells. The heart pro- pels blood out of its chambers into blood vessels to be transported to all body tissues.

Lymphatic system

The role of the lymphatic system comple- ments that of the cardiovascular system. Its organs include lymphatic vessels, lymph nodes, and other lymphoid organs such as the spleen and tonsils (Figure 1.2g). When fluid is leaked into tissues from the blood, lymphatic vessels return it to the bloodstream so that there is enough blood to con- tinuously circulate through the body. The lymph nodes and other lymphoid organs help to cleanse the blood and house white blood cells involved in immunity.

respiratory system

The job of the respiratory system is to keep the body supplied with oxygen and to remove car- bon dioxide. The respiratory system consists of the nasal passages, pharynx, larynx, trachea, bron- chi, and lungs (Figure 1.2h). Within the lungs are tiny air sacs. Gases are exchanged with the blood through the thin walls of these air sacs.

Digestive system

The digestive system is basically a tube running through the body from mouth to anus. The organs of the digestive system include the oral cavity (mouth), esophagus, stomach, small and large intestines, and rectum plus a number of accessory organs (liver, salivary glands, pancreas, and oth- ers) (Figure 1.2i). Their role is to break down food and deliver the resulting nutrients to the blood for dispersal to body cells. The breakdown activities

1

Forms the external body covering; protects deeper tissue from injury; synthesizes vitamin D; location of sensory receptors (pain, pressure, etc.) and sweat and oil glands.

(a) Integumentary System

Skin

Hair

Fingernails

Allows manipulation of the environment, locomotion, and facial expression; maintains posture; produces heat.

(c) Muscular System

Skeletal muscles

Protects and supports body organs; provides a framework the muscles use to cause movement; blood cells are formed within bones; stores minerals.

(b) Skeletal System

Cartilages

Joint

Bones

Glands secrete hormones that regulate processes such as growth, reproduction, and nutrient use by body cells.

Blood vessels transport blood, which carries oxygen, nutrients, hormones, carbon dioxide, wastes, etc.; the heart pumps blood.

Fast-acting control system of the body; responds to internal and external changes by activating appropriate muscles and glands.

Heart

Blood vessels

Thyroid gland (parathyroid glands on posterior aspect)

Pineal gland

Pituitary gland

Thymus gland

Adrenal glands

Pancreas

Testis (male)

Ovary (female)

Brain

Sensory receptor

Spinal cord

Nerves

(d) Nervous System (e) Endocrine System (f) Cardiovascular System

Figure 1.2 The body’s organ systems. (Figure continues on page 32.)

Lymph nodes

Lymphatic vessels

Trachea

Larynx

Bronchi

Lungs

Nasal cavity

Pharynx Esophagus

Stomach

Small intestine

Large intestine

Rectum

Oral cavity

Ovary

Uterine tube

Uterus

Vagina

Mammary glands (in breasts)

Seminal vesicles

Prostate gland

Penis Testis

Scrotum

Ureter

Urinary bladder

Urethra

Kidney

Picks up fluid leaked from blood vessels and returns it to blood; disposes of debris in the lymphatic stream; houses white blood cells involved in immunity.

(g) Lymphatic System

Keeps blood constantly supplied with oxygen and removes carbon dioxide; the gaseous exchanges occur through the walls of the air sacs of the lungs.

(h) Respiratory System

Breaks food down into absorbable nutrients that enter the blood for distribution to body cells; indigestible foodstuffs are eliminated as feces.

(i) Digestive System

Eliminates nitrogen-containing wastes from the body; regulates water, electrolyte, and acid-base balance of the blood.

(j) Urinary System Overall function of the reproductive system is production of offspring. Testes produce sperm and male sex hormone; ducts and glands aid in delivery of viable sperm to the female reproductive tract. Ovaries produce eggs and female sex hormones; remaining structures serve as sites for fertilization and development of the fetus. Mammary glands of female breasts produce milk to nourish the newborn.

(k) Male Reproductive System (l) Female Reproductive System

Figure 1.2 (continued) The body’s organ systems.

Chapter 1: The Human Body: An Orientation 33

1Maintaining Life ➔ Learning Objectives

□□ List eight functions that humans must perform to maintain life.

□□ List the five survival needs of the human body.

necessary Life Functions Now that we have introduced the structural levels composing the human body, a question naturally follows: What does this highly organized human body do? Like all complex animals, human beings maintain their boundaries, move, respond to envi- ronmental changes, take in and digest nutrients, carry out metabolism, dispose of wastes, repro- duce themselves, and grow.

Organ systems do not work in isolation; instead, they work together to promote the well-being of the entire body (Figure 1.3). Because this theme is emphasized throughout this text, it is worthwhile to identify the most important organ systems contrib- uting to each of the necessary life functions. Also, as you study this figure, you may want to refer to the more detailed descriptions of the organ systems just provided (pp. 29–33 and in Figure 1.2).

Maintaining Boundaries

Every living organism must be able to maintain its boundaries so that its “inside” remains distinct from its “outside.” Every cell of the human body is surrounded by an external membrane that sepa- rates its contents from the outside interstitial fluid (fluid between cells) and allows entry of needed substances while generally preventing entry of potentially damaging or unnecessary substances. The body as a whole is also enclosed by the integumentary system, or skin. The integumen- tary system protects internal organs from drying out (which would be fatal), from pathogens, and from the damaging effects of heat, sunlight, and an unbelievable number of chemical substances in the external environment.

Movement

Movement includes all the activities promoted by the muscular system, such as propelling ourselves from one place to another (by walking, swim- ming, and so forth) and manipulating the exter- nal environment with our fingers. The skeletal system provides the bones that the muscles pull on as they work. Movement also occurs when substances such as blood, foodstuffs, and urine

that begin in the mouth are completed in the small intestine. From that point on, the major function of the digestive system is to reabsorb water. The undigested food that remains in the tract leaves the body through the anus as feces. The liver is considered a digestive organ because the bile it produces helps to break down fats. The pan- creas, which delivers digestive enzymes to the small intestine, has both endocrine and digestive functions.

urinary system

A normal part of healthy body function is the production of waste by-products, which must be disposed of. One type of waste contains nitro- gen (examples are urea and uric acid), which results when the body cells break down proteins and nucleic acids, which are genetic information molecules. The urinary system removes the nitrogen-containing wastes from the blood and flushes them from the body in urine. This sys- tem, often called the excretory system, is com- posed of the kidneys, ureters, bladder, and urethra (Figure 1.2j). Other important functions of this sys- tem include maintaining the body’s water and salt (electrolyte) balance, regulating the acid-base bal- ance of the blood, and helping to regulate normal blood pressure.

reproductive system

The role of the reproductive system is to pro- duce offspring. The male testes produce sperm. Other male reproductive system structures are the scrotum, penis, accessory glands, and the duct system, which carries sperm to the outside of the body (Figure 1.2k). The female ovaries produce eggs, or ova; the female duct system consists of the uterine tubes, uterus, and vagina (Figure 1.2l). The uterus provides the site for the development of the fetus (immature infant) once fertilization has occurred.

Did You Get It? 3. At which level of structural organization is the

stomach? At which level is a glucose molecule? 4. Which organ system includes the trachea, lungs,

nasal cavity, and bronchi? 5. Which system functions to remove wastes and help

regulate blood pressure?

For answers, see Appendix A.

pan). You do not need to think about it—it just happens! Likewise, when the amount of carbon dioxide in your blood rises to a dangerously high level, your breathing rate speeds up to blow off the excess carbon dioxide.

Because nerve cells are highly irritable and can communicate rapidly with each other via elec- trical impulses, the nervous system bears the major responsibility for responsiveness. However, all body cells are responsive to some extent.

are propelled through the internal organs of the cardiovascular, digestive, and urinary systems, respectively.

responsiveness

Responsiveness, or irritability, is the ability to sense changes (stimuli) in the environment and then to react to them. For example, if you acci- dentally touch a hot pan, you involuntarily pull your hand away from the painful stimulus (the

Interstitial fluid

Heart

Nutrients

Food

Feces are excreted

Urine is excreted

O2

O2

CO2

CO2

Digestive system Takes in nutrients, digests them (part of metabolism), and excretes unabsorbed matter (feces)

Integumentary system Protects the body as a whole from the external environment by maintaining boundaries

Urinary system Excretes nitrogen-containing wastes and excess ions

Nutrients and wastes pass between blood and cells via the interstitial fluid

Cardiovascular system Via the blood, distributes oxygen and nutrients to all body cells and delivers wastes and carbon dioxide to disposal organs

Respiratory system Takes in oxygen, which is required for metabolism, and excretes carbon dioxide

Blood

Figure 1.3 Examples of interrelationships among organ systems that illustrate life functions.

Chapter 1: The Human Body: An Orientation 35

1 by an increase in the number of cells. For growth to occur, cell-constructing activities must occur at a faster rate than cell-destroying ones. Hormones released by the endocrine system play a major role in directing growth.

survival needs The goal of nearly all body systems is to maintain life. However, life is extraordinarily fragile and requires that several factors be available. These factors, which we will call survival needs, include nutrients (food), oxygen, water, and appropriate temperature and atmospheric pressure.

Nutrients, which the body takes in through food, contain the chemicals used for energy and cell building. Carbohydrates are the major energy- providing fuel for body cells. Proteins and, to a lesser extent, fats are essential for building cell structures. Fats also cushion body organs and pro- vide reserve fuel. Minerals and vitamins are required for the chemical reactions that go on in cells and for oxygen transport in the blood.

All the nutrients in the world are useless unless oxygen is also available. Because the chemical reactions that release energy from foods require oxygen, human cells can survive for only a few minutes without it. It is made available to the blood and body cells by the cooperative efforts of the respiratory and cardiovascular systems.

Water accounts for 60 to 80 percent of body weight, depending on the age of the individual. It is the single most abundant chemical substance in the body and provides the fluid base for body secre- tions and excretions. We obtain water chiefly from ingested foods or liquids, and we lose it by evapora- tion from the lungs and skin and in body excretions.

If chemical reactions are to continue at life- sustaining levels, normal body temperature must be maintained. If body temperature drops below 37°C (98.6°F), metabolic reactions become slower and slower and finally stop. If body tem- perature is too high, chemical reactions proceed too rapidly, and body proteins begin to break down. At either extreme, death occurs. Most body heat is generated by the activity of the skeletal muscles and dissipated via blood circulating close to the skin surface or by the evaporation of sweat.

The force exerted on the surface of the body by the weight of air is referred to as atmospheric pressure. Breathing and the exchange of oxygen and carbon dioxide in the lungs depend on

Digestion

Digestion is the process of breaking down ingested food into simple molecules that can then be absorbed into the blood. The nutrient-rich blood is then distributed to all body cells by the cardiovascular system, where body cells use these simple molecules for energy and raw materials.

Metabolism

Metabolism is a broad term that refers to all chemical reactions that occur within the body and all of its cells. It includes breaking down com- plex substances into simpler building blocks (as in digestion), making larger structures from smaller ones, and using nutrients and oxygen to produce molecules of adenosine triphosphate (ATP), the energy-rich molecules that power cellular activi- ties. Metabolism depends on the digestive and respiratory systems to make nutrients and oxygen available to the blood and on the cardiovascu- lar system to distribute these needed substances throughout the body. Metabolism is regulated chiefly by hormones secreted by the glands of the endocrine system.

Excretion

Excretion is the process of removing excreta (ek-skre′tah), or wastes, from the body. Several organ systems participate in excretion. For exam- ple, the digestive system rids the body of indigest- ible food residues in feces, the urinary system disposes of nitrogen-containing metabolic wastes in urine, and the skin disposes of various waste products as components of sweat.

reproduction

Reproduction, the production of offspring, can occur on the cellular or organismal level. In cel- lular reproduction, the original cell divides, pro- ducing two identical daughter cells that may then be used for body growth or repair. Reproduction of the human organism is the task of the organs of the reproductive system, which produce sperm and eggs. When a sperm unites with an egg, a fertilized egg forms, which then develops into a baby within the mother’s body. The function of the reproductive system is regulated very precisely by hormones of the endocrine system.

Growth

Growth can be an increase in cell size or an increase in body size that is usually accomplished (Text continues on page 38.)

36

Currently PET can reveal signs of trou- ble in people with undiagnosed Alzheimer’s disease (AD) because regions of beta-amyloid accumulation (a defining characteristic of AD) show up in brilliant red and yellow when that molecule is tagged. By tagging glucose, we can observe that brain tissue in areas of impairment or areas with Alzheimer’s plaques use far less glucose compared to normal brain tissue as shown in photo (d).

Perhaps the best known of these newer imaging devices is computed tomography (cT), a refined version of X ray that eliminates the confusion resulting from images of overlapping structures. A CT scanner takes “pic- tures” of a thin slice of the body, about as thick as a dime. Different tis- sues absorb the radiation in varying amounts. The device’s computer translates this information into a detailed, cross-sectional picture of the body region scanned; see photo (e). CT scans are at the forefront in evalu- ating most problems that affect the brain and abdomen, and their clarity has all but eliminated exploratory sur- gery. Special ultrafast CT scanners have produced a technique called dynamic spatial reconstruction (Dsr), which provides three- dimensional images of body organs from any angle. It also allows organ movements and changes in internal volumes to be observed at normal speed, in slow motion, and at a spe- cific moment in time. The greatest value of DSR has been to visualize the heart beating and blood flowing through blood vessels. This allows medical personnel to assess heart defects, constricted blood vessels, and the status of coronary bypass grafts.