Exercise and Senescence

Other than the mere passage of time, senescence results from obesity and insufficient exercise more than from any other causes. Conversely, good nutrition and exercise are the best ways to slow its progress. There is no clear evidence that exercise will prolong your life, but there is little doubt that it improves the quality of life in old age. It maintains endurance, strength, and joint mobility while it reduces the incidence and severity of hypertension, osteoporosis, obesity, and diabetes...

Properties and Types of Sensory Receptors

When you have completed this section, you should be able to define receptor and sense organ list the four kinds of information obtained from sensory receptors, and describe how the nervous system encodes each type and outline three ways of classifying receptors. A receptor is any structure specialized to detect a stimulus. Some receptors are simple nerve endings, whereas others are sense organs nerve endings combined with connective, epithelial, or muscular tissues that enhance or moderate the...

Insight 202 Clinical Application

Normal Blood Pressure Male

An aneurysm is a weak point in a blood vessel or in the heart wall. It forms a thin-walled, bulging sac that pulsates with each beat of the heart and may eventually rupture. In a dissecting aneurysm, blood pools between the tunics of a vessel and separates them, usually because of degeneration of the tunica media. The most common sites of aneurysms are the abdominal aorta, the renal arteries, and the arterial circle at the base of the brain. Even without hemorrhaging, aneurysms can cause pain...

The Digestive System

General Anatomy and Digestive Processes 940 Digestive Function 940 General Anatomy 940 Relationship to the Peritoneum 941 Regulation of the Digestive Tract 942 Saliva and the Salivary Glands 946 The Pharynx 948 The Esophagus 948 Swallowing 948 The Stomach 949 Gross Anatomy 950 Innervation and Circulation 950 The Stomach Wall 950 Gastric Secretions 952 Gastric Motility 955 Vomiting 955 Digestion and Absorption 955 Protection of the Stomach 956 Regulation of Gastric Function 956 The Liver,...

Relaxation

When its work is done, a muscle fiber relaxes and returns to its resting length. This is achieved by the steps shown in figure 11.11. 14. Nerve signals stop arriving at the neuromuscular junction, so the synaptic knob stops releasing ACh. 15. As ACh dissociates (separates) from its receptor, acetylcholinesterase breaks it down into fragments that cannot stimulate the muscle. The synaptic knob reabsorbs these fragments for recycling. All of this happens continually while the muscle is being...

Table 2010 Venous Drainage of the Upper Limb

Table 20.9 briefly noted the subclavian veins that drain each arm. This table begins distally in the forearm and traces venous drainage to the subclavian vein (fig. 20.34). 1. The palmar digital veins drain each finger into the superficial venous palmar arch. 2. The metacarpal veins parallel the metacarpal bones and drain blood from the hand into the deep venous palmar arch. Both the superficial and deep venous palmar arches are anastomoses between the next two veins, which are the major deep...

Review of Key Concepts

The chromatin in a cell nucleus is composed of DNA and protein. The chromatin is elaborately coiled to prevent damage to the DNA. 2. Nucleic acids are polymers of nucleotides. A nucleotide is composed of a sugar, a phosphate group, and a nitrogenous base. 3. Cytosine (C), thymine (T), and uracil (U) are single-ringed nitrogenous bases called pyrimidines. Adenine (A) and guanine (G) are double-ringed bases called purines. 4. The DNA molecule is like a twisted ladder, with backbones of sugar...

The Skin as a Barrier

The skin bears the brunt of most physical injuries to the body, but it resists and recovers from trauma better than other organs do. The toughness of keratin and strength of the epidermal desmosomes make the skin a barrier that is not easily breached. Few infectious organisms can penetrate the skin on their own. Those that do either rely on accidental breaks in the skin or have life cycles that involve vectors animals such as mosquitoes, fleas, lice, and ticks, with mouthparts strong enough to...

Chapter Review

Fertilization and Preembryonic Development (p. 1090) 1. Sperm must travel to the distal one-third of the uterine tube if they are to encounter the egg before it dies. This traveling, or sperm migration, may be aided by the cervical mucus, female orgasm, and chemical attractants emitted by the egg. 2. Freshly ejaculated sperm cannot fertilize an egg. They undergo capacitation, becoming capable of fertilization, as they migrate. 3. When a sperm encounters an egg, it releases enzymes from its...

Hypersensitivity

Hypersensitivity is an excessive, harmful immune reaction to antigens that most people tolerate. It includes reactions to tissues transplanted from another person (alloimmu-nity), abnormal reactions to one's own tissues (autoimmunity), and allergies,21 which are reactions to environmental antigens. Such antigens, called allergens, occur in mold, dust, pollen, vaccines, bee and wasp venoms, toxins from poison ivy and other plants, and foods such as nuts, milk, eggs, and shellfish. Drugs such as...

Forms of Immunity

In the late 1800s, it was discovered that immunity can be transferred from one animal to another by way of the blood serum. In the mid-1900s, however, it was found that serum does not always confer immunity sometimes only donor lymphocytes do so. Thus, we now recognize two types of immunity, called cellular and humoral immunity, although these two mechanisms interact extensively and often respond to the same pathogen. Cellular (cell-mediated) immunity is based on the action of lymphocytes that...

Monoamines

Peptide Anatomy

Melatonin is synthesized from the amino acid tryptophan and the other monoamines from the amino acid tyrosine. Thyroid hormone (TH) is an unusual case in three respects (1) its synthesis begins with the production of a large protein called thyroglobulin, although this protein is not part of the finished TH (2) TH is composed of two tyrosine molecules linked together and (3) the synthesis of TH requires a mineral, iodine. TH is synthesized in the follicles of the thyroid gland by the process...

Skin Markings

Hemangiomas18 (he-MAN-jee-OH-mas), or birthmarks, are patches of discolored skin caused by benign tumors of the dermal blood capillaries. Capillary hemangiomas (strawberry birthmarks) are bright red to deep purple and are slightly swollen they usually disappear in childhood. Cavernous hemangiomas (port wine stains) are flat, are duller in color, and last for life. Freckles and moles are tan to black aggregations of melanocytes. Freckles are flat melanized patches that vary with heredity and...

Synovial Joints

When you have completed this section, you should be able to describe the anatomy of a synovial joint and its associated structures describe the six types of synovial joints list and demonstrate the types of movements that occur at diarthroses discuss the factors that affect the range of motion of a joint give an anatomical example of a first-, second-, and third-class lever and explain why each is classified as it is and relate the concept of mechanical advantage to the power and speed of joint...

Capacitation

Spermatozoa can reach the distal uterine tube within 5 to 10 minutes of ejaculation, but they cannot fertilize an egg for about 10 hours. While migrating, they undergo a process of capacitation that makes it possible to penetrate an egg. Prior to ejaculation, the membrane of the sperm head contains a substantial amount of cholesterol, which toughens it and prevents premature release of the acroso-mal enzymes. This avoids wastage of sperm and enzymatic damage to the spermatic ducts. After...

Melatonin SAD and PMS

There seems to be a relationship between melatonin and mood disorders, including depression and sleep disturbances. Some people experience a mood dysfunction called seasonal affective disorder (SAD), especially in winter when the days are shorter and they get less exposure to sunlight, and in extreme northern and southern latitudes where sunlight may be dim to nonexistent for months at a time. SAD thus affects about 20 of the population in Alaska but only 2.5 in Florida. The symptoms which...

Table 142 The Cranial Nerves

Picture Testing Cranial Nerve

Origins of proprioceptive fibers are not tabulated they are the muscles innervated by the motor fibers. Nerves listed as mixed or sensory are agreed by all authorities to be either mixed or purely sensory nerves. Nerves classified as predominantly motor or sensory are traditionally classified that way but contain some fibers of the other type. Composition Sensory Function Smell Origin Olfactory mucosa in nasal cavity Termination Olfactory bulbs beneath frontal lobe of brain Cranial passage...

Anaerobic Fermentation

The fate of pyruvic acid depends on whether or not oxygen is available. In an exercising muscle, the demand for ATP may exceed the supply of oxygen, and the only ATP the cells can make under these circumstances is the 2 ATP produced by glycolysis. Cells that lack mitochondria, such as erythro-cytes, are also restricted to making ATP by this method. But glycolysis would quickly come to a halt if the reaction stopped at pyruvic acid. Why Because it would use up the supply of NAD+, which is needed...

Chapter Opener 6 Ed

Reschke Peter Arnold 6.2b, 6.3a The McGraw-Hill Companies, Inc. Dennis Strete, photographer 6.3b From Tissues and Organs A Text-Atlas of Scanning Electron Microscopy, Richard G. Kessel and Randy H. Kardon, published by W.H. Freeman and Company 1979. 6.3c SPL Custom Medical Stock Photos 6.4 Meckes Ottawa Photo Researchers, Inc. 6.6 The McGraw-Hill Companies, Inc. Dennis Strete, photographer 6.7 (top) Tom McHugh Photo Researchers, Inc. 6.7 (bottom) The McGraw-Hill Saladin Anatomy & I End...

Connectiv

Reabsorbed Fetus

Interactions Between the DIGESTIVE SYSTEM and Other Organ Systems indicates ways in which this system affects other systems indicates ways in which other systems affect this one The digestive system provides all other systems with nutrients in a form usable for cellular metabolism and building of tissues Skin plays a role in the synthesis of calcitriol, needed for calcium and phosphorus absorption by the small intestine Small intestine adjusts calcium absorption in proportion to the needs of...

The Integumentary System

Structure of the Skin and Subcutaneous Tissue 192 Types and Distribution of Hair 201 Structure of the Hair and Follicle 202 Connective Issues 212 Chapter Review 213 and Pseudoscience of Hair Analysis 202 Clinical Application UVA, UVB, and Sunscreens 210 Clinical Application Skin Grafts and Artificial Skin 211 To understand this chapter, it is important that you understand or brush up on the following concepts Stratified squamous epithelium (p. 161) Collagenous fibers (p. 167) Areolar and dense...

True or False

Determine which five of the following statements are false, and briefly explain why. 1. The esophagus is protected from abrasion by a keratinized stratified squamous epithelium. 2. All cells of a pseudostratified columnar epithelium contact the basement membrane. 3. Not all skeletal muscle is attached to bones. 4. The stroma of a gland does not secrete anything. 5. In all connective tissues, the matrix occupies more space than the cells do. 6. Adipocytes are limited to adipose tissue. 7. Tight...

The Temporomandibular Joint

The temporomandibular joint (TMJ) is the articulation of the condyle of the mandible with the mandibular fossa of the temporal bone (fig. 9.18). You can feel its action by pressing your fingertips against the jaw immediately anterior to the ear while opening and closing your mouth. This joint combines elements of condyloid, hinge, and gliding joints. It functions in a hingelike fashion when the mandible is elevated and depressed, it glides slightly forward when the jaw is protracted to take a...

Antigens

An antigen15 (Ag) is any molecule that triggers an immune response. Some antigens are free molecules such as venoms and toxins others are components of plasma membranes and bacterial cell walls. Small universal molecules such as glucose and amino acids are not antigenic if they were, our immune systems would attack the nutrients and other molecules essential to our very survival. Most antigens have molecular weights over 10,000 amu and are generally complex molecules that are unique to each...

The Muscular System

The Structural and Functional Organization of Muscles 326 The Functions of Muscles 326 Connective Tissues of a Muscle 326 General Anatomy of Skeletal Muscles 328 Coordinated Action of Muscle Groups 328 Intrinsic and Extrinsic Muscles 329 Muscles of Facial Expression 330 Muscles of Chewing and Swallowing 335 Muscles Acting on the Head 343 Muscles of the Pelvic Floor 350 Muscles Acting on the Shoulder and Upper Limb 352 Muscles Acting on the Scapula 352 Muscles Acting on the Humerus 356 Muscles...

Overview of Volume Changes

Nurse Unity

An additional perspective on the cardiac cycle can be gained if we review the volume changes that occur. This balance sheet is from the standpoint of the left ventricle, but for reasons explained shortly, these numbers also must be true of the right. The volumes vary somewhat from one person to another and depend on a person's state of activity. Passively added to the ventricle during atrial diastole Total end-diastolic volume (EDV) 130 mL Stroke volume (SV) ejected by ventricular Leaves...

The Circulatory System Blood

Functions and Properties of Blood 680 Nonprotein Nitrogenous Substances 684 Quantities of Erythrocytes and Hemoglobin 691 Erythrocyte Death and Disposal 691 Abnormalities of Leukocyte Count 699 Hemostasis The Control of Bleeding 702 Platelet Plug Formation 703 The Fate of Blood Clots 706 Prevention of Inappropriate Coagulation 706 Clinical Application Starvation and Plasma Protein Deficiency 682 Evolutionary Medicine The Packaging of Hemoglobin 690 Medical History Charles Drew Blood Banking...

What Sets This Book Apart

Those who have not used or reviewed previous editions will want to know how this book differs from others. The sequence of chapters and placement of some topics in this book differ from others. While I felt it was risky to depart from tradition in my first edition, reviewer comments have overwhelmingly supported my intuition that these represent a more logical way of presenting the Saladin Anatomy & I Front Matter I Preface I I The McGraw-Hill Physiology The Unity of Companies, 2003 Form and...

S

Saccule, 600 ,606, 607 Sacral canal, 268 Sacral region of spinal cord, 482, 483 surface anatomy of, 33 , 395 Sacroiliac joint, 268, 1071 Sacrum, 262, 262 , 263, 267-268, 268 Sagittal plane, 31, 31 Sagittal sections, 31, 31 Sagittal suture, 251, 251 St. Martin, Alexis, 977i-978i Saline, 108, 933i Saliva, 946-948 antibodies in, 825t, 946 HIV in, 831 Salivary amylase, 83, 946, 948, 969 Salivary glands, 943 , 946-947, 947 autonomic control of, 526, 568 ,570, 571, 572 , 573, 577 Salivation, 947-948...

The Near Response

Emmetropia52 (EM-eh-TRO-pee-uh) is a state in which the eye is relaxed and focused on an object more than 6 m (20 ft) away, the light rays coming from that object are essentially parallel, and the rays are focused on the retina without effort. (An emmetropic eye does not need a corrective lens to focus the image.) If the gaze shifts to something closer, light rays from the source are too divergent to be focused without effort. In other words, the eye is automatically focused on things in the...

Nitrogenous Wastes

A waste is any substance that is useless to the body or present in excess of the body's needs. A metabolic waste, more specifically, is a waste substance produced by the body. Thus the food residue in feces, for example, is a waste but not a metabolic waste, since it was not produced by the body and, indeed, never entered the body's tissues. Metabolism produces a great quantity of wastes that are lethal to cells if allowed to accumulate. Some of the Saladin Anatomy & I 23. The Urinary System...

Alcohol and Alcoholism

Alcohol is not only a popular mind-altering drug but is also regarded in many cultures as a food staple. As a source of empty calories, an addictive drug, and a toxin, it can have a broad spectrum of adverse effects on the body. Alcohol is rapidly absorbed from the digestive tract about 20 of it in the stomach and 80 in the proximal small intestine. Carbonation, Saladin Anatomy & I 26. Nutrition and I Text I The McGraw-Hill Physiology The Unity of Metabolism Companies, 2003 Form and...

Functions of the Liver

We have seen that the liver plays a central role in carbohydrate metabolism. Additional liver functions (table 26.7) were described in previous chapters and will be described later in this chapter. Except for phagocytosis, all of these are performed by the cuboidal hepatocytes described in chapter 25. Such functional diversity is remarkable in light of the uniform structure of these cells. Because of the wide range of functions performed by the liver, degenerative liver diseases such as...

Testing Your Comprehension

How would glomerular filtration rate be affected by kwashiorkor (see p. 683) 2. A patient produces 55 mL of urine per hour. Urea concentration is 0.25 mg mL in her blood plasma and 8.6 mg mL in her urine. (a) What is her rate of renal clearance for urea (b) About 95 of adults excrete urea at a rate of 12.6 to 28.6 g day. Is this patient above, within, or below this range Show how you calculated your answers. 3. A patient with poor renal perfusion is treated with an ACE inhibitor and goes into...

Glycogen Metabolism

Figure 26.7 Summary of the Sources of ATP Generated by the Complete Oxidation of Glucose. ATP is quickly used after it is synthesized it is an energy-transfer molecule, not an energy-storage molecule. Therefore, if the body has an ample amount of ATP and there is still more glucose in the blood, it does not produce and store excess ATP but converts the glucose to other compounds better suited for energy storage namely glycogen and fat. Fat synthesis is considered later. Here we consider the...

Aging and Senescence

When you have completed this section, you should be able to define senescence and distinguish it from aging describe some major changes that occur with aging in each organ system summarize some current theories of senescence and be able to explain how exercise and other factors can slow the rate of senescence. Like Ponce de Leon searching for the legendary fountain of youth in Florida, people yearn for a way to preserve Figure 29.16 Down Syndrome. (a)A child with Down syndrome (right) plays...

Excitement and Plateau

The excitement phase is characterized by vasocongestion (swelling of the genitals with blood), myotonia (muscle tension), and increases in heart rate, blood pressure, and pulmonary ventilation. The bulbourethral glands secrete their fluid during this phase. The excitement phase can be initiated by a broad spectrum of erotic stimuli sights, sounds, aromas, touch and even by dreams or thoughts. Conversely, emotions can inhibit sexual response and make it difficult to function when a person is...

The Circulatory System The Heart

Overview of the Cardiovascular System 716 Size, Shape, and Position of the Heart 717 Blood Flow Through the Heart 724 The Coronary Circulation 724 Cardiac Muscle and the Cardiac Conduction System 726 Structure of Cardiac Muscle 726 Metabolism of Cardiac Muscle 727 The Cardiac Conduction System 727 Electrical and Contractile Activity of the Heart 728 Physiology of the SA Node 728 Impulse Conduction to the Myocardium 728 Electrical Behavior of the Myocardium 729 Blood Flow, Heart Sounds, and the...

Think About It

As described, does the previous experiment conclusively prove that the second frog's heart slowed as a result of something released by the vagus nerves If you were Loewi, what control experiment would you do to rule out alternative explanations Following Loewi's work, the idea of electrical communication between cells fell into disrepute. Now, however, we realize that some neurons, neuroglia, and cardiac and single-unit smooth muscle (see chapter 11) do indeed have electrical synapses, where...

Sv

(5) Antigen fragments displayed on macrophage surface IfSjAntigen and '.' A enzyme mix in phagolysosome Figure 21.19 T Cells Inspecting Macrophages in a Lymph Node for Antigen Presentation. From R. G. Kessel and R. H. Kardon, Tissues and Organs A Text-Atlas of Scanning Electron Microscopy (W. H. Freeman & Co., 1979). Figure 21.19 T Cells Inspecting Macrophages in a Lymph Node for Antigen Presentation. From R. G. Kessel and R. H. Kardon, Tissues and Organs A Text-Atlas of Scanning Electron...

Glomerular Filtration Rate

Assessment of kidney disease often calls for a measurement of GFR. We cannot determine GFR from urea excretion for two reasons (1) some of the urea in the urine is secreted by the renal tubule, not filtered by the glomeru-lus, and (2) much of the urea filtered by the glomerulus is reabsorbed by the tubule. To measure GFR ideally requires a substance that is not secreted or reabsorbed at all, so that all of it in the urine gets there by glomerular filtration. There doesn't appear to be a single...

Physiology The Unity ofCompanies 2003 Form and Function Third Edition

Linking of proteins and DNA and the misfolding and other structural defects in proteins may cause increasing cellular dysfunction. The cumulative effects of free radical damage and increased incidence of autoimmune disease may be other factors in senescence. 16. Longevity is known to be partially hereditary. Natural selection has presumably been unable to eliminate genes that cause some of the diseases of old age because such genes have no effects that natural selection can act on until after...

Light and Dark Adaptation

Light adaptation occurs when you go from the dark into bright light. If you wake up in the night and turn on a lamp, at first you see a harsh glare you may experience discomfort from the overstimulated retinas. Your pupils quickly constrict to reduce the intensity of stimulation, but color vision and visual acuity (the ability to see fine detail) remain below normal for 5 to 10 minutes the time needed for pigment bleaching to adjust retinal sensitivity to this light intensity. The rods bleach...

Lungs

After birth, the pulmonary circuit is the only route in which the arterial blood contains less oxygen than the venous blood. The pulmonary arteries have thin distensible walls with less elastic tissue than the systemic arteries. Thus, they have a BP of only 25 10. Capillary hydrostatic Saladin Anatomy & I 20. The Circulatory System I Text I The McGraw-Hill Physiology The Unity of Blood Vessels and Companies, 2003 Form and Function, Third Circulation Edition Chapter 20 The Circulatory System...

M

R., 671 -672 Macromolecules, 72 Macrophage-activating factor, 821 Macrophages, 167, 810 alveolar, 810, 849, 852 antigen-presenting function, 804, 817, 818 cortisol, effect of, 833i in healing, 184 , 186, 235, in inflammation, 812t, 813 in lymphatic tissue, 804, 805 in nervous tissue, 451, 453, 454 in nonspecific defense, 199 origin of, 688 phagocytosis by, 112 stimulated by TH cells, 819 types of, 810 Macula densa, 885 , 890, 890 , 891 Macula lutea, 612 , 615, 615 Macula sacculi,...

The Nerve Muscle Relationship

When you have completed this section, you should be able to explain what a motor unit is and how it relates to muscle contraction describe the structure of a junction where a nerve fiber meets a muscle fiber and explain why a cell has an electrical charge difference across its plasma membrane and, in general terms, how this relates to muscle contraction. Skeletal muscle never contracts unless it is stimulated by a nerve (or artificially with electrodes). If its nerve connections are severed or...

Proteins

Protein constitutes about 12 to 15 of the body's mass 65 of it is in the skeletal muscles. Proteins are responsible for muscle contraction and the motility of cilia and flagella. They are a major structural component of all cellular membranes, with multiple important roles such as membrane receptors, pumps, ion channels, and cell-identity markers. Fibrous proteins such as collagen, elastin, and keratin make up much of the structure of bone, cartilage, tendons, ligaments, skin, hair, and nails....

Nonprotein Nitrogenous Substances

Blood plasma contains several important nitrogenous compounds in addition to protein notably amino acids and nitrogenous wastes. The amino acids come from the digestion of dietary protein or the catabolism of tissue proteins. Nitrogenous wastes are toxic end products of catabolism (see table 18.3). The most abundant is urea, a product of amino acid catabolism. Nitrogenous wastes are normally cleared from the blood and excreted by the kidneys at a rate that balances their rate of production.

Vitamins

Vitamins were originally named with letters in the order of their discovery, but they also have chemically descriptive names such as ascorbic acid (vitamin C) and riboflavin (vitamin B2). Most vitamins must be obtained from the diet (table 26.4), but the body synthesizes some of them from precursors called provitamins niacin from the amino acid tryptophan, vitamin D from cholesterol, and vitamin A from carotene, which is abundantly present in carrots, squash, and other yellow vegetables and...

Other Factors Affecting Bone

At least 20 more hormones, growth factors, and vitamins affect osseous tissue in complex ways that are still not well understood (table 7.2). Bone growth is especially rapid in puberty and adolescence, when surges of growth hormone, estrogen, and testosterone promote ossification. These hormones stimulate rapid multiplication of osteogenic cells, matrix deposition by osteoblasts, and multiplication and hypertrophy of the chondrocytes in the metaphyses. Adolescent girls grow faster than boys and...

The Pancreas

Take Glucose Red Cells

The elongated spongy pancreas is located retroperi-toneally, inferior and dorsal to the stomach (fig. 17.11). It is approximately 15 cm long and 2.5 cm thick. Most of it is an exocrine digestive gland, but scattered through the exocrine tissue are endocrine cell clusters called pancreatic islets (islets of Langerhans20). There are 1 to 2 million islets, but they constitute only about 2 of the pancreatic tissue. The islets secrete at least five hormones and 20Paul Langerhans (1847-88), German...

Anatomy of Selected Diarthroses

When you have completed this section, you should be able to identify the major anatomical features of the jaw, shoulder, elbow, hip, knee, and ankle joints and explain how the anatomical differences between these joints are related to differences in function. We now examine the gross anatomy of certain diarthroses. It is beyond the scope of this book to discuss all of them, but the ones selected here most often require medical attention and many of them have a strong bearing on athletic...

Supportive Cells Neuroglia

When you have completed this section, you should be able to name the cells that aid neuron function and state their functions describe the myelin sheath that is formed around certain nerve fibers and explain its importance describe the relationship of unmyelinated nerve fibers to their supportive cells and explain how damaged nerve fibers regenerate. Saladin Anatomy amp I 12. Nervous Tissue I Text I I The McGraw-Hill Physiology The Unity of Companies, 2003 Form and Function, Third Edition 450...

Social Functions

Pictures Nonverbal Facial Expression

The integumentary system plays an important role in the social relations of all vertebrate animals by enabling them to identify members of their own species and distinguish the sexes. Some mammals recognize each other by the color and distribution of hair. Animals may also accept or reject one another's company and choose mates based on the appearance of the integument, which may indicate an animal's state of health. Thus, it is not surprising that animals allocate a lot of time to grooming....

Hydrogen Ions

Ultimately, pulmonary ventilation is adjusted to maintain the pH of the brain. Hydrogen ions cannot freely cross the blood-CSF barrier, but CO2 does. In the CSF, CO2 reacts with water and releases H . H then strongly stimulates the central chemoreceptors, which transmit signals to the inspiratory center. Normally the blood has a pH of 7.40 0.05. Deviation from this range is called acidosis when the pH falls below 7.35 and alkalosis when it rises above 7.45. The normal PCO2 of the blood is 40 3...

Wwwmhhecomsaladin3

The Online Learning Center provides a wealth of information fully organized and integrated by chapter. You will find practice quizzes, interactive activities, labeling exercises, flashcards, and much more that will complement your learning and understanding of anatomy and physiology. Saladin Anatomy amp I 15. The Autonomic Nervous I Text I The McGraw-Hill Physiology The Unity of and Visceral Reflexes Companies, 2003 Autonomic neurons in the myenteric plexus of the digestive tract The Autonomic...

Heat Production and Loss

Most body heat comes from exergonic energy-releasing chemical reactions such as nutrient oxidation and ATP use. A little heat is generated by joint friction, blood flow, and other movements. At rest, most heat is generated by the brain, heart, liver, and endocrine glands the skeletal muscles contribute about 20 to 30 of the total resting heat. Increased muscle tone or exercise greatly increases heat generation in the muscles, however in vigorous exercise, they produce 30 to 40 times as much...

Testing Your Recall

Which of the following muscles is the prime mover in spitting out a mouthful of liquid 2. Each muscle fiber has a sleeve of areolar connective tissue around it called 3. Which of these is not a suprahyoid muscle 4. Which of these muscles is an extensor of the neck 5. Which of these muscles of the pelvic floor is the deepest a. superficial transverse perineus 6. Which of these actions is not performed by the trapezius 7. Both the hands and feet are acted upon by a muscle or muscles called c....

Use as Fuel

Citric Acid Cycle Diagrams

The first step in using amino acids as fuel is to deaminate them. After the -NH2 group is removed, the remainder of the molecule is called a keto acid. Depending on which amino acid is involved, the resulting keto acid may be converted to pyruvic acid, acetyl-CoA, or one of the acids of the citric acid cycle fig. 26.10 . It is important to note that some of these reactions are reversible. When there is a Saladin Anatomy amp I 26. Nutrition and I Text I The McGraw-Hill Physiology The Unity of...

Body Heat and Thermoregulation

When you have completed this section, you should be able to identify the principal sources of body heat describe some factors that cause variations in body temperature define and contrast the different forms of heat loss describe how the hypothalamus monitors and controls body temperature and describe conditions in which the body temperature is excessively high or low. Heat generation must be matched by heat loss in order to maintain a stable internal body temperature. Hypothermia, an...

Urine Formation III Water Conservation

When you have completed this section, you should be able to explain how the collecting duct and antidiuretic hormone regulate the volume and concentration of urine and explain how the kidney maintains an osmotic gradient in the renal medulla that enables the collecting duct to function. The kidney serves not just to eliminate metabolic waste from the body but to prevent excessive water loss in doing so, and thus to support the body's fluid balance. As the kidney returns water to the tissue...

Composition of

Air is a mixture of gases, each of which contributes a share, called its partial pressure, to the total atmospheric pressure table 22.4 . Partial pressure is abbreviated P followed Saladin Anatomy amp I 22. The Respiratory System I Text I The McGraw-Hill Physiology The Unity of Companies, 2003 Form and Function, Third Edition 860 Part Four Regulation and Maintenance by the formula of the gas. The partial pressure of nitrogen is Pn2, for example. Nitrogen constitutes about 78.6 of the atmosphere...

Which Taste Sensations Would Be Lost After Damage To The Facial Nerve

Which taste sensations could be lost after damage to 1 the facial nerve or 2 the glossopharyngeal nerve A fracture of which cranial bone would most likely eliminate the sense of smell Answer the following questions to test your understanding of the preceding section 10. What is the difference between a lingual papilla and a taste bud Which is visible to the naked eye 11. List the primary taste sensations and discuss their adaptive significance survival value . 12. Which cranial nerves carry...

Metabolic States and Metabolic Rate

When you have completed this section, you should be able to define the absorptive and postabsorptive states explain what happens to carbohydrates, fats, and proteins in each of these states describe the hormonal and nervous regulation of each state define metabolic rate and basal metabolic rate and describe some factors that alter the metabolic rate. Your metabolism changes from hour to hour depending on how long it has been since your last meal. The absorptive fed state lasts about 4 hours...

Bones Associated with the Skull

Seven bones are closely associated with the skull but not considered part of it. These are the three auditory ossicles in each middle-ear cavity and the hyoid bone beneath the chin. The auditory ossicles29 named the malleus hammer , incus anvil , and stapes STAY-peez stirrup are discussed in connection with hearing in chapter 16. The hyoid30 bone is a slender bone between the chin and larynx fig. 8.16 . It is one of the few bones that does not articulate with any other. The hyoid is suspended...

Orgasm and Ejaculation

The orgasm,36 or climax, is a short but intense reaction that lasts 3 to 15 seconds and usually is marked by the discharge of semen. The heart rate increases to as high as 180 beats per minute, blood pressure rises proportionately, and the respiratory rate becomes as high as 40 breaths per minute. From the standpoint of producing offspring, the Saladin Anatomy amp I 27. The Male Reproductive I Text I The McGraw-Hill Physiology The Unity of System Companies, 2003 Form and Function, Third Edition...

Blood Pressure

Blood pressure BP is the force that the blood exerts against a vessel wall. It can be measured within a blood vessel or heart chamber by inserting a catheter or needle connected to an external manometer pressure-measuring device . For routine clinical purposes, however, the measurement of greatest interest is the systemic arterial BP at a point close to the heart. As mentioned in chapter 19, we customarily measure it with a sphygmomanometer at the brachial artery of the arm. It is easy to...

The General Senses

When you have completed this section, you should be able to list several types of somesthetic receptors describe the projection pathways for the general senses and explain the mechanisms of pain and the spinal blocking of pain signals. Receptors for the general senses are relatively simple in structure and physiology. They consist of one or a few sensory nerve fibers and, usually, a sparse amount of connective tissue. These receptors are shown in table 16.1.

Sperm and Semen

When you have completed this section, you should be able to describe the stages of meiosis and contrast meiosis with mitosis describe the sequence of cell types in spermatogenesis, and relate these to the stages of meiosis describe the role of the sustentacular cell in spermatogenesis draw or describe a sperm cell and describe the composition of semen and functions of its components. The most significant event of puberty is the onset of sper-matogenesis. This is a process in which germ cells...

The Middle

The auditory ossicles provide no amplification vibrations of the stapes against the inner ear normally have the same amplitude as vibrations of the eardrum against the malleus. Why have auditory ossicles, then There are two answers to this. One is that the eardrum, which moves in air, vibrates easily, whereas the stapes footplate must vibrate against the fluid of the inner ear. This fluid puts up a much greater resistance to motion than air does. If airborne sound waves struck the footplate...

Regulation of Intake

Intake Ium Nursing School

Fluid intake is governed mainly by thirst, which is controlled by the mechanisms shown in figure 24.3. Dehydration reduces blood volume and pressure and raises blood osmolarity. The hypothalamus has a nucleus called the thirst center that responds to multiple signs of dehydration 1 angiotensin II, produced in response to falling blood pressure 2 antidiuretic hormone, released in response to rising blood osmolarity and 3 signals from osmoreceptors, neurons in the hypothalamus that monitor the...

Achondroplastic Dwarfism

Achondroplastic24 ah-con-dro-PLAS-tic dwarfism is a condition in which the long bones of the limbs stop growing in childhood, while the growth of other bones is unaffected. As a result, a person has a short stature but a normal-sized head and trunk fig. 7.12 . As its name implies, achondroplastic dwarfism results from a failure of cartilage growth specifically, failure of the chondrocytes in zones 2 and 3 of the metaphysis to multiply and enlarge. This is different from pituitary dwarfism, in...

Glossary

This glossary defines approximately 1,000 terms. They are not necessarily the most important ones in the book, but they are terms that are reintroduced most often and, for lack of space, are not redefined each time they arise. The index indicates where you can find definitions or explanations of additional terms. Terms are defined only in the sense that they are used in this book. Some have broader meanings, even within biology and medicine, that are beyond its scope. Terms that are commonly...

General Properties of Receptors

Receptive Field Skin

All sensory receptors are transducers. A transducer is any device that converts one form of energy to another a microphone, light bulb, or gasoline engine, for example. Sensory transducers convert stimulus energy into electrochemical energy a meaningful pattern of action potentials. This process of conversion is called sensory transduction. The effect of a stimulus on a receptor is to produce a type of local potential called a receptor potential a graded voltage change across the plasma...

Blood Cell Production

When you have completed this section, you should be able to explain where blood is produced in fetuses, children, and adults describe the stages of blood cell production and state the factors that influence its rate and explain how uncommitted stem cells become committed to forming specific types of blood cells. Saladin Anatomy amp I 18. The Circulatory System I Text I The McGraw-Hill Physiology The Unity of Blood Companies, 2003 Form and Function, Third Edition A knowledge of hemopoiesis4...

Electrophysiology of Neurons

When you have completed this section, you should be able to explain why a cell has an electrical charge difference voltage across its membrane explain how stimulation of a neuron causes a local electrical change in its membrane explain how local electrical changes generate a nerve signal and explain how the nerve signal is transmitted down an axon. The nervous system has intrigued scientists and philosophers since ancient times. The Roman physician Galen thought that the brain pumped a vapor...

Body Temperature

Normal body temperature depends on when, where, and in whom it is measured. Body temperature fluctuates about 1 C 1.8 F in a 24-hour cycle. It tends to be lowest in the early morning and highest in the late afternoon. Temperature also varies from one place in the body to another. The most important body temperature is the core temperature the temperature of organs in the cranial, thoracic, and abdominal cavities. Rectal temperature is relatively easy to measure and gives an estimate of core...

Muscular Dystrophy and Myasthenia Gravis

Famous People With Myasthenia Gravis

Muscular dystrophy14 is a collective term for several hereditary diseases in which the skeletal muscles degenerate, lose strength, and are gradually replaced by adipose and fibrous tissue. This new connective tissue impedes blood circulation, which in turn accelerates muscle degeneration in a fatal spiral of positive feedback. The most common form of the disease is Duchenne15 muscular dystrophy DMD , caused by a sex-linked recessive allele. Like other sex-linked traits see chapter 4 , DMD is...

Pedagogy

Several features of this book are designed to facilitate the student's learning. I divide each chapter into typically five or six segments of just a few pages each, with a list of learning objectives at the beginning and a list of Before You Go On content review questions at the end of each one. This enables students to set tangible goals for short study periods and to assess their progress before moving on. A amp P students must assimilate a large working vocabulary. This is far easier and...

Pitch

Audible Frequency Range

Pitch is our sense of whether a sound is high treble or low bass . It is determined by the frequency at which the sound source, eardrum, and other parts of the ear vibrate. One movement of a vibrating object back and forth is called a cycle, and the number of cycles per second cps or hertz, Hz is called frequency. The lowest note on a piano, for example, is 27.5 Hz, middle C is 261 Hz, and the highest note is 4,176 Hz. The most sensitive human ears can hear frequencies from 20 to 20,000 Hz. The...

Functions of the Kidneys

Metabolism constantly produces a variety of waste products that can poison the body if not eliminated. The most fundamental role of the kidneys is to eliminate these wastes and homeostatically regulate the volume and composition of the body fluids. All of the following processes are aspects of kidney function They filter blood plasma, separate wastes from the useful chemicals, and eliminate the wastes while returning the rest to the bloodstream. They regulate blood volume and pressure by...

Central Control of Autonomic Function

When you have completed this section, you should be able to describe how the autonomic nervous system is regulated by the brain and somatic nervous system. In spite of its name, the ANS is not an independent nervous system. All of its output originates in the CNS, and it receives input from the cerebral cortex, hypothalamus, medulla oblongata, and somatic branch of the PNS. In this section we briefly consider how the ANS is influenced by these other levels of the nervous system. Figure 15.10...

Thyroid and Parathyroid Disorders

Endemic Goiter

Congenital hypothyroidism is thyroid hyposecretion present from birth it was formerly called cretinism, now regarded as an insensitive term. Severe or prolonged adult hypothyroidism can cause myxedema MIX-eh-DEE-muh . Both syndromes are described in table 17.8, and both can be treated with oral thyroid hormone. A goiter is any pathological enlargement of the thyroid gland. Endemic goiter fig. 17.25 is due to dietary Figure 17.25 Endemic Goiter. The thyroid gland has hypertrophied as a result of...

Hearing and Equilibrium

When you have completed this section, you should be able to identify the properties of sound waves that account for pitch and loudness describe the gross and microscopic anatomy of the ear explain how the ear converts vibrations to nerve signals and discriminates between sounds of different intensity and pitch explain how the vestibular apparatus enables the brain to interpret the body's position and movements and describe the pathways taken by auditory and vestibular signals to the brain....

Leukocyte Production

Leukopoiesis LOO-co-poy-EE-sis is the production of white blood cells see fig. 18.4 . It begins when some hemocytoblasts differentiate into three types of committed cells 1. B progenitors, destined to become B lymphocytes 2. Tprogenitors, which become T lymphocytes and 3. granulocyte-macrophage colony-forming units, which become granulocytes and monocytes. These committed cells have receptors for colony-stimulating factors CSFs . Mature lymphocytes and macrophages secrete several types of CSFs...

Adrenal Disorders

Cushing26 syndrome is excess cortisol secretion owing to any of several causes ACTH hypersecretion by the pituitary, ACTH-secreting tumors, or hyperactivity of the adrenal cortex independently of ACTH. Cushing syndrome disrupts carbohydrate and protein metabolism, leading to hyperglycemia, hypertension, muscular weakness, and edema. Muscle and bone mass are lost rapidly as protein is catabolized. Some patients exhibit abnormal fat deposition between the shoulders buffalo hump or in the face...

The Spinal Cord

Such autonomic responses as the defecation and micturition urination reflexes are integrated in the spinal cord see details in chapters 23 and 25 . Fortunately, the brain is able to inhibit these responses consciously, but when injuries sever the spinal cord from the brain, the auto-nomic spinal reflexes alone control the elimination of urine and feces. Table 15.6 describes some dysfunctions of the auto-nomic nervous system. Answer the following questions to test your understanding of the...

Galvani Volta and Animal Electricity

The invention of modern dry cells can be traced to studies of frog muscle by Italian anatomist Luigi Galvani 1737-98 . He suspended isolated frog legs from a copper hook and noticed that they twitched when touched with an iron scalpel. He attributed this to animal electricity in the legs. The physicist Alessandro Volta 1745-1827 investigated Galvani's discovery further. He concluded that when two different metals such as the copper hook and iron scalpel are separated by an electrolyte solution...

Voluntary Control

Although breathing usually occurs automatically, without our conscious attention, we obviously can hold our breath, take a deep breath, and control ventilation while speaking or singing. This control originates in the motor cortex of the frontal lobe of the cerebrum, which sends impulses down the corticospinal tracts to the respiratory neurons in the spinal cord, bypassing the brainstem respiratory centers. There are limits to voluntary control. Temperamental children may threaten to hold their...

Visual Pigments

The visual pigment of the rods is called rhodopsin ro-DOP-sin , or visual purple. Each molecule consists of two major parts moieties a protein called opsin and a vitamin A derivative called retinal rhymes with pal , also known as retinene fig. 16.34 . Opsin is embedded in the disc membranes of the rod's outer segment. All rod cells contain a single kind of rhodopsin with an absorption peak at a wavelength of 500 nm. The rods are less sensitive to light of other wavelengths. In cones, the...

Atrial Natriuretic Peptide

Atrial natriuretic peptide ANP is secreted by the atrial myocardium of the heart in response to high blood pressure. ANP has four actions that result in the excretion of more salt and water in the urine, thus reducing blood volume and pressure 1. It dilates the afferent arteriole and constricts the efferent arteriole, thus increasing the glomerular filtration rate. 2. It antagonizes the angiotensin-aldosterone mechanism by inhibiting the adrenal cortex from secreting aldosterone and inhibiting...

Electrolyte Balance

When you have completed this section, you should be able to describe the physiological roles of sodium, potassium, calcium, chloride, and phosphate describe the hormonal and renal mechanisms that regulate the concentrations of these electrolytes and state the term for an excess or deficiency of each electrolyte and describe the consequences of these imbalances. Electrolytes are physiologically important for multiple reasons They are chemically reactive and participate in metabolism, they...

Carbohydrate Metabolism

When you have completed this section, you should be able to describe the principal reactants and products of each major step of glucose oxidation contrast the functions and products of anaerobic fermentation and aerobic respiration explain where and how cells produce ATP and describe the production, function, and use of glycogen. Most dietary carbohydrate is burned as fuel within a few hours of absorption. Although three monosaccharides are absorbed from digested food glucose, galactose, and...

Carbohydrates

A well-nourished adult has about 440 g of carbohydrate in the body, most of it in three places about 325 g of muscle glycogen, 90 to 100 g of liver glycogen, and 15 to 20 g of blood glucose. Sugars function as a structural component of other molecules including nucleic acids, glycoproteins, glyco-lipids, ATP, and related nucleotides GTP, cAMP, etc. , and they can be converted to amino acids and fats. Most of the body's carbohydrate, however, serves as fuel an easily oxidized source of chemical...

Parathyroid Hormone

Pth And Renal Funciton

Parathyroid hormone PTH is secreted by the parathyroid glands, which adhere to the posterior surface of the thyroid gland see fig. 17.9 . These glands release PTH when the blood calcium is too low. A mere 1 drop in the blood calcium level doubles the secretion of PTH. Saladin Anatomy amp 7. Bone Tissue Text The McGraw-Hill Physiology The Unity of Companies, 2003 Form and Function, Third Edition Figure 7.15 Calcitriol Synthesis and Action. Starting at the upper left, ultraviolet rays stimulate...

Table 142 The Cranial Nerves continued

Orbital Nerve Info

Oculomotor OC-you-lo-MO-tur Nerve Function Eye movements, opening of eyelid, constriction of pupil, focusing, proprioception Termination Somatic fibers lead to levator palpebrae superioris, superior, medial, and inferior rectus, and inferior oblique muscles parasympathetic fibers enter eyeball and lead to constrictor of iris and ciliary muscle of lens Cranial passage Superior orbital fissure Effects of damage Drooping eyelid, dilated pupil, inability to move eye in certain directions,...

Electrical and Contractile Activity of the Heart

When you have completed this section, you should be able to explain why the SA node fires spontaneously and rhythmically explain how the SA node excites the myocardium describe the unusual action potentials of cardiac muscle and relate them to the contractile behavior of the heart and interpret a normal electrocardiogram. In this section, we examine how the electrical events in the heart produce its cycle of contraction and relaxation. Contraction is called systole SIS-toe-lee and relaxation is...

Neurotransmitters and Related Messengers

Pictures Microcephaly Infants

More than 100 confirmed or suspected neurotransmitters have been identified since Loewi discovered acetylcholine. Neurotransmitters fall into three major categories according to chemical composition fig. 12.18 . Some of the best-known ones are listed in table 12.3. Parts of the brain referred to in this table will become familiar to you as you study chapter 14, and you may wish to refer back to this table then to enhance your understanding of brain function. 1. Acetylcholine is in a class by...

The Urinary Bladder

The urinary bladder fig. 23.20 is a muscular sac on the floor of the pelvic cavity, inferior to the peritoneum and posterior to the pubic symphysis. It is covered by parietal peritoneum on its flattened superior surface and by a fibrous adventitia elsewhere. Its muscularis, called the detrusor27 deh-TROO-zur muscle, consists of three lay ers of smooth muscle. The mucosa has a transitional epithelium, and in the relaxed bladder it has conspicuous wrinkles called rugae28 ROO-gee . The openings of...

P

Pancreas PAN-cree-us A gland of the upper abdominal cavity, near the stomach, that secretes digestive enzymes and sodium bicarbonate into the duodenum and secretes hormones into the blood. pancreatic islets PAN-cree-AT-ic EYE-lets Small clusters of endocrine cells in the pancreas that secrete insulin, glucagon, somatostatin, and other intercellular messengers also called islets of Langerhans. fig. 17.11 papilla pa-PILL-uh A conical or nipplelike structure, such as a lingual papilla of the...