Info

Where Image Heart Plumnary Trunk

The cardiovascular system transports blood between the body cells and organs such as the lungs, intestines, and kidneys that communicate with the external environment. posterior of the sternum, the vertebral column, and the large blood vessels emerging from the heart (see figs. 1.9, 15.4 and reference plates 56 and 57). Between the parietal and visceral layers of the pericardium is a space, the pericardial cavity, that contains a small volume of serous fluid that the pericardial membranes...

Simple Squamous Epithelium

Simple squamous epithelium consists of a single layer of thin, flattened cells. These cells fit tightly together, somewhat like floor tiles, and their nuclei are usually broad and thin (fig. 5.1). Substances pass rather easily through simple squa-mous epithelium, which is common at sites of diffusion and filtration. For instance, simple squamous epithelium lines the air sacs (alveoli) of the lungs where oxygen and carbon dioxide are exchanged. It also forms the walls of capillaries, lines the...

L

Labor (la'bor) The process of childbirth. p. 918 labyrinth (lab'i-rinth) The system of connecting tubes within the inner ear, including the cochlea, vestibule, and semicircular canals. p. 471 lacrimal gland (lak'rii-mal gland) Tear- secreting gland. p. 481 lactase (lak'tais) Enzyme that catalyzes breakdown of lactose into glucose and galactose. p. 719 lactate (lak'tait) Lactic acid. p. 309 lactation (lak-ta'shun) Production of milk by the mammary glands. p. 922 lacteal (lak'te-al) A lymphatic...

Sex Hormones

Cells in the inner zone (zona reticularis) of the adrenal cortex produce sex hormones. These hormones are male (adrenal androgens), but some of them are converted Helps regulate the concentration of extracellular electrolytes by conserving sodium ions and excreting potassium ions Electrolyte concentrations in body fluids and renin-angiotensin mechanism Decreases protein synthesis, increases fatty acid release, and stimulates glucose synthesis from noncarbohydrates CRH from the hypothalamus and...

Hormone Action page 504

Endocrine glands secrete hormones that affect target cells possessing specific receptors. a. Each kind of hormone has a special molecular structure and is very potent. b. Chemically, hormones are steroids, amines, peptides, proteins, or glycoproteins. (1) Steroid hormones enter target cells and combine with receptors to form complexes. (2) These complexes activate specific genes in the nucleus, which direct synthesis of specific proteins. (3) The degree of cellular response is proportional to...

Bone

Bone (osseous tissue) is the most rigid connective tissue. Its hardness is largely due to mineral salts, such as calcium phosphate and calcium carbonate, in its matrix. This intercellular material also contains a great amount of collagen, whose fibers flexibly reinforce the mineral components of bone. Bone internally supports body structures. It protects vital structures in the cranial and thoracic cavities and is an attachment for muscles. Bone also contains red marrow, which forms blood...

Characteristics of Red Blood Cells

Red blood cells, or erythrocytes (e-rith'ro-sitz), are tiny, approximately 7.5 im in diameter. They are biconcave disks which means that they are thin near their centers and thicker around their rims (fig. 14.4). This special shape is an adaptation for the red blood cell's function of transporting gases it increases the surface area through which gases can diffuse. The shape also places the cell membrane closer to oxygen-carrying hemoglobin molecules within the cell. Because of its shape, a red...

Lymphatic Capillaries

Lymphatic capillaries are microscopic, closed-ended tubes. They extend into the interstitial spaces, forming complex networks that parallel the networks of the blood capillaries (fig. 16.2). The walls of the lymphatic capillar ies are similar to those of the blood capillaries. Each consists of a single layer of squamous epithelial cells. These thin walls make it possible for tissue fluid (interstitial fluid) from the interstitial space to enter the lymphatic capillaries. Fluid inside a...

Static Equilibrium

Medial Geniculate Body

The organs of static equilibrium are located within the vestibule, a bony chamber between the semicircular canals and the cochlea. More specifically, the membranous labyrinth inside the vestibule consists of two expanded chambers a utricle and a saccule. The larger utricle communicates with the saccule and the membranous portions of the semicircular canals the sac-cule, in turn, communicates with the cochlear duct (fig. 12.18). The utricle and saccule each has a small patch of hair cells and...

Clinical Applications

I.1 Ultrasonography and Magnetic Resonance Imaging 2.1 Radioactive Isotopes Reveal Physiology 42 2.2 Ionizing Radiation A Legacy of the Cold War 46 2.3 CT Scanning and PET Imaging 58 3.1 Faulty Ion Channels Cause Disease 70 3.2 The Blood-Brain Barrier 73 3.3 Disease at the Organelle Level 80 3.4 Cloning 102 4.1 Overriding a Block in Glycolysis 117 4.2 DNA Makes History 126 4.3 Gene Amplification 132 4.4 Phenylketonuria 136 5.1 Abnormalities of Collagen 153 5.2 Tissue Engineering 162 6.1 Skin...

Plantar Flexors

The gastrocnemius (gastrok-ne'me-us) on the back of the leg forms part of the calf. It arises by two heads from the femur. The distal end of this muscle joins the strong cal-caneal tendon (Achilles tendon), which descends to the heel and attaches to the calcaneus. The gastrocnemius is a powerful plantar flexor of the foot that aids in pushing the body forward when a person walks or runs. It also flexes the leg at the knee (figs. 9.40 and 9.41). Strenuous athletic activity may partially or...

Synaptic Potentials

Neuron Mcgraw Hilll Anatomy

Synaptic potentials are graded and can depolarize or hy-perpolarize the receiving cell membrane. For example, if a neurotransmitter binds to a postsynaptic receptor and opens sodium ion channels, the ions diffuse inward, depolarizing the membrane, possibly triggering an action potential. This type of membrane change is called an excitatory postsynaptic potential (EPSP), and it lasts for about 15 milliseconds. If a different neurotransmitter binds other receptors and increases membrane...

Your Link to Media Support

The Online Learning Center is your link to electronic learning resources that will help you review and understand the chapter content. Chapter 6 Skin and the Integumentary System Visit the Student OLC on your text website at http www.mhhe.com shier Chapter Quiz Flashcards Test your mental endurance with the online flashcards. Randomize the deck and practice the definitions of key glossary terms. Review additional readings for a solid tie-in to chapter content. Browse health-related topics and...

Chapter Summary

Chemistry deals with the composition of substances and changes in their composition. Biochemistry is the chemistry of living things. Matter is anything that has weight and takes up space. a. Naturally occurring matter on earth is composed of ninety-two elements. b. Elements occur most frequently in chemical combinations called compounds. c. Elements are composed of atoms. d. Atoms of different elements vary in size, weight, and ways of interacting. a. An atom consists of electrons surrounding a...

Visceral Pain

Visceral Pain Pathway

As a rule, pain receptors are the only receptors in viscera whose stimulation produces sensations. Pain receptors in these organs respond differently to stimulation than those associated with surface tissues. For example, localized damage to intestinal tissue during surgical procedures may not elicit any pain sensations, even in a conscious person. However, when visceral tissues are subjected to more widespread stimulation, as when intestinal tissues are stretched or when the smooth muscles in...

Two Approaches to Gene Therapy

Gene Therapy Side Effects

There are two basic types of gene therapy. Heritable gene therapy, also known as germline gene therapy, introduces the genetic change into a sperm, egg, or fertilized egg, which corrects each cell of the resulting individual. The change is repeated in the person's gametes and can be passed to the next generation. Heritable gene therapy is considered to be impractical and unethical in humans and will likely never be done, at least with government

Muscles that Move the

Muscles That Move The Pectoral Girdle

The arm is one of the more freely movable parts of the body because muscles connect the humerus to regions of the pectoral girdle, ribs, and vertebral column. These muscles can be grouped according to their primary actions flexion, extension, abduction, and rotation (figs. 9.27, 9.28, 9.29 reference plates 62, 63, 64 table 9.7).

Blood Vessel Summary

The cardiovascular system provides oxygen and nutrients to tissues and removes wastes. 1. Size and location of the heart a. The heart is about 14 centimeters long and 9 centimeters wide. b. It is located within the mediastinum and rests on the diaphragm. a. A layered pericardium encloses the heart. b. The pericardial cavity is a space between the visceral and parietal layers of the pericardium. a. The wall of the heart has three layers. b. These layers include an epicardium, a myocardium, and...

Pancreatic Juice

Blood Vessels Pancreas

Pancreatic juice contains enzymes that digest carbohydrates, fats, proteins, and nucleic acids. The carbohydrate-digesting enzyme, pancreatic amylase, splits molecules of starch or glycogen into double sugars (disaccharides). The fat-digesting enzyme, pancreatic lipase, breaks triglyceride molecules into fatty acids and monoglyc-erides. (A monoglyceride molecule consists of one fatty acid bound to glycerol.) The protein-splitting (proteolytic) enzymes are trypsin, chymotrypsin, and...

Central Venous Pressure

Because all the veins, except those of the pulmonary circuit, drain into the right atrium, the pressure within this heart chamber is called central venous pressure. This pressure is of special interest because it affects the pressure within the peripheral veins. For example, if the heart is beating weakly, the central venous pressure increases, and blood backs up in the venous network, raising its pressure too. However, if the heart is beating forcefully, the central venous pressure and the...

Distribution of Ions

Potassium ions (K+) are the major intracellular positive ion (cation), and sodium ions (Na+) are the major extracellular cation. The distribution is created largely by the sodium-potassium pump (Na+ K+ pump), which actively transports sodium ions out of the cell and potassium ions into the cell. It is also in part due to channels in the cell membrane that determine membrane permeability to these ions. These channels, formed by membrane proteins, can be quite selective that is, a particular...

Control of Cell Division

Turtle Salivary Gland

How often a cell divides is strictly controlled and varies with cell type. Skin cells, blood-forming cells, and cells that line the intestine, for example, divide often and continually. In contrast, cells of the liver divide a specific number of times and then cease they are alive and specialized, but no longer divide. If, however, injury or sur gery removes some liver cells, the remaining cells may be stimulated to divide again, regenerating the organ. Some cells, such as certain nerve cells,...

Lumbosacral Plexuses

The lumbosacral (lumbo-sa'kral) plexuses are formed by the last thoracic nerve and the lumbar, sacral, and coc-cygeal nerves. These networks of nerve fibers extend from the lumbar region of the back into the pelvic cavity, giving rise to a number of motor and sensory fibers associated with the lower abdominal wall, external genitalia, buttocks, thighs, legs, and feet. The major branches of these plexuses include the following (fig. 11.35) 1. The obturator nerves supply the adductor muscles of...

Muscles of the Abdominal Wall

The walls of the chest and pelvic regions are supported directly by bone, but those of the abdomen are not. Instead, the anterior and lateral walls of the abdomen are composed of layers of broad, flattened muscles. These muscles connect the rib cage and vertebral column to the pelvic girdle. A band of tough connective tissue, called the linea alba, extends from the xiphoid process of the sternum to the symphysis pubis. It is an attachment for some of the abdominal wall muscles. Contraction of...

Clinical Terms Related to the Cardiovascular System

Anastomosis (ah-nasto-mo'sis) Connection between two blood vessels, sometimes produced surgically. angiospasm (an'je-o-spazm) Muscular spasm in the wall of a blood vessel. arteriography (arte-re-og'rah-fe) Injection of radiopaque solution into the vascular system for an X-ray examination of arteries. asystole (a-sis'to-le) Condition in which the myocardium fails to contract. cardiac tamponade (kar'de-ak tampo-nad') Compression of the heart by fluid accumulating within the pericardial cavity....

Figure 911

(a) In a resting sarcomere, tropomyosin blocks binding sites on the actin filaments. (b) In the presence of calcium, troponin alters the position of tropomyosin to expose the binding sites. It is important to remember that ATP is necessary for both muscle contraction and for muscle relaxation. The trigger for contraction is the increase in cytosolic calcium in response to stimulation by ACh from a motor neuron. A few hours after death, the skeletal muscles partially contract, fixing the joints....

Actions of Autonomic Neurotransmitters

Ganglion Spinal Cord Tissue

As in the case of stimulation at neuromuscular junctions (see chapter 9, p. 302) and synapses (see chapter 10, p. 363), the actions of autonomic neurotransmitters result from their binding to protein receptors in the membranes of effector cells. Receptor binding alters the membrane. For example, the membrane's permeability to certain ions may increase, and in smooth muscle cells, an action potential followed by muscular contraction may result. Similarly, a gland cell may respond to a change in...

Cardiac Conduction System

Throughout the heart are clumps and strands of specialized cardiac muscle tissue whose fibers contain only a few myofibrils. Instead of contracting, these areas initiate and distribute impulses (cardiac impulses) throughout the myocardium. They comprise the cardiac conduction system, which coordinates the events of the cardiac cycle. A key portion of this conduction system is the sinoatrial node (S-A node), a small, elongated mass of specialized cardiac muscle tissue just beneath the...

Review Exercises

Explain how the lymphatic system is related to the cardiovascular system. 2. Trace the general pathway of lymph from the interstitial spaces to the bloodstream. 3. Identify and describe the locations of the major lymphatic trunks and collecting ducts. 4. Distinguish between tissue fluid and lymph. 5. Describe the primary functions of lymph. 6. Explain why physical exercise promotes lymphatic circulation. 7. Explain how a lymphatic obstruction leads to edema. 8. Describe the structure of a lymph...

1

The trillions of cells in an adult human ultimately derive by mitosis from the original fertilized egg cell. As different genes are turned on or off in different cells, the characteristics of specific cell types emerge. (Relative cell sizes are not to scale.) Shier-Butler-Lewis I. Levels of Organization 3. Cells The McGraw-Hill Human Anatomy and Companies, 2001 The human body is built of more than 200 types of specialized, or differentiated, cell types. Once a cell activates certain subsets of...

Odontoid Process With Blood Vessels

(a) Lateral view of a typical thoracic vertebra. (b) Adjacent vertebrae join at their articulating processes. (c) Superior view of a typical thoracic vertebra. Fovea dentis (facet that articulates with dens of axis) Facet that articulates with occipital condyle Dens (odontoid process) Superior articular facet Anterior articular facet for atlas Dens Dens (odontoid process) Superior articular facet Anterior articular facet for atlas Dens Superior view of the (a) atlas and (b) axis. (c) Lateral...

Transitional Epithelium

Unstretched Transitional Epithelium

Transitional epithelium (uroepithelium) is specialized to change in response to increased tension. It forms the inner lining of the urinary bladder and lines the ureters and part of the urethra. When the wall of one of these organs contracts, the tissue consists of several layers of cuboidal cells however, when the organ is distended, the tissue stretches, and the physical relationships among the cells change. While distended, the tissue appears to contain only a few layers of cells (fig. 5.9)....

Side Upper Body Muscles

Sternocleidomastoid And Rectus Abdominis

Human female torso, showing the anterior surface on one side and the superficial muscles exposed on the other side. (m. stands for muscle v. stands for vein.) .Common carotid a. . Internal jugular v. . Thyroid gland External intercostal m. Coracobrachialis m. .Common carotid a. . Internal jugular v. . Thyroid gland External intercostal m. Coracobrachialis m. Human male torso, with the deeper muscle layers exposed. (n. stands for nerve a. stands for artery.) Human male torso, with the deeper...

Part A

Briefly describe the early development of knowledge about the human body. 2. Distinguish between anatomy and physiology. 3. How does a biological structure's form determine its function Give an example. 4. List and describe ten characteristics of life. 6. List and describe five requirements of organisms. 7. Explain how the idea of homeostasis relates to the five requirements you listed in item 6. 8. Distinguish between heat and temperature. 9. What are two types of pressures that may act upon...

Composition of Bile

Composition Bile

Bile (bil) is a yellowish-green liquid that hepatic cells continuously secrete. In addition to water, it contains bile salts, bile pigments, cholesterol, and electrolytes. Of these, bile salts are the most abundant. They are the only bile substances that have a digestive function. Branch Branch of hepatic of hepatic portal vein artery The paths of blood and bile within a hepatic lobule. Central canal (blood flow out of liver)

Reticular Connective Tissue

Reticular Tissue Labeled Liver

Reticular connective tissue is composed of thin, collage-nous fibers in a three-dimensional network. It supports Adipose tissue cells contain large fat droplets that push the nuclei close to the cell membranes (75x micrograph enlarged to 300x). Adipose tissue cells contain large fat droplets that push the nuclei close to the cell membranes (75x micrograph enlarged to 300x). Reticular connective tissue is a network of thin collagenous fibers, which contains numerous fibroblasts and white blood...

Olfactory Nerve Pathways

Once olfactory receptors are stimulated, nerve impulses travel along their axons through tiny openings in the cribriform plates of the ethmoid bone. These fibers (which form the first cranial nerves) synapse with neurons located in the enlargements of the olfactory bulbs, structures that lie on either side of the crista galli of the ethmoid bone (see figs. 7.26 and 12.6). Within the olfactory bulbs, the sensory impulses are analyzed, and as a result, additional impulses travel along the...

Plate Forty Seven

Shaped neuroglial cell. ax-, axle axon cylindrical nerve fiber that carries impulses away from a neuron cell body. dendr-, tree dendrite branched nerve fiber that serves as the receptor surface of a neuron. ependym-, tunic ependyma neuroglial cells that line spaces within the brain and spinal cord. -lemm, rind or peel neurilemma sheath that surrounds the myelin of a nerve fiber. moto-, moving motor neuron neuron that stimulates a muscle to contract or a gland to release a secretion. multi-,...

Jpp

Abdominal (ab-dom'i-nal) Pertaining to the portion of the body between the diaphragm and the pelvis. p. 24 abdominal cavity (ab-dom'i-nal kav'i-te) The space between the diaphragm and the pelvic inlet that contains the abdominal viscera. p. 12 abdominopelvic cavity (ab-domi-no-pel'vik kav'i-te) The space between the diaphragm and the lower portion of the trunk of the body. p. 11 abduction (ab-duk'shun) Movement of a body part away from the midline. p. 276 absorption (ab-sorp'shun) The taking in...

Clinical Terms Related to the Digestive System

Achalasia (akah-la'ze-ah) Failure of the smooth muscle to relax at some junction in the digestive tube, such as that between the esophagus and stomach. achlorhydria (ahklor-hi'dre-ah) Lack of hydrochloric acid in gastric secretions. aphagia (ah-fa'je-ah) Inability to swallow. cholecystitis (kole-sis-ti'tis) Inflammation of the gallbladder. cholelithiasis (kole-li-thi'ah-sis) Stones in the gallbladder. cholestasis (kole-sta'sis) Blockage in bile flow from the gallbladder. cirrhosis (si-ro'sis)...

Muscles that Move the Hand

Extensor Carpi Radialis Longus

Movements of the hand include movements of the wrist and fingers. Many muscles move the wrist, hand, and fingers. They originate from the distal end of the humerus and from the radius and ulna. The two major groups of these muscles are flexors on the anterior side of the forearm and extensors on the posterior side. Figures 9.30, 9.31, 9.32, reference plate 65, and table 9.9 concern these muscles. The muscles that move the hand include the following Flexor carpi radialis longus Flexor carpi...

Regulation of the Cardiac Cycle

The volume of blood pumped changes to accommodate cellular requirements. For example, during strenuous exercise, skeletal muscles require more blood, and heart rate increases in response. Since the S-A node normally controls heart rate, changes in this rate often involve fac tors that affect the pacemaker, such as the motor impulses carried on the parasympathetic and sympathetic nerve fibers (see figs. 11.39, 11.40, 15.23, and 15.38). The parasympathetic fibers that innervate the heart arise...

Ytc

Tracheostomy Blood Vessels

Lung cancer may begin as a tiny tumor growing in an alveolus, a microscopic air sac (125x). the tiny, conelike corniculate cartilages. These cartilages are attachments for muscles that help regulate tension on the vocal cords during speech and aid in closing the larynx during swallowing. The cuneiform cartilages are small, cylindrical structures in the mucous membrane between the epiglot-tic and the arytenoid cartilages. They stiffen the soft tissues in this region. Inside the larynx, two pairs...

Smooth Muscle Tissue

Fetal Skeletal Muscle

Smooth muscle tissue (fig. 5.29) is called smooth because its cells lack striations. Smooth muscle cells are shorter than those of skeletal muscle and are spindle-shaped, each with a single, centrally located nucleus. This tissue comprises the walls of hollow internal organs, such as the stomach, intestines, urinary bladder, uterus, and blood vessels. Unlike skeletal muscle, smooth muscle usually cannot be stimulated to contract by conscious efforts. Thus, its actions are involuntary. For...

Cardiac Muscle Fibers

Functional Syncytium Heart

Recall that cardiac muscle fibers function like those of skeletal muscles, but the fibers connect in branching When Tina Orbacz was pregnant with her second child in 1990, she attributed her increasing fatigue to her pregnant state. But a month after her son's birth, she was even more exhausted. Plus, she had lost weight during her pregnancy, not gained it. Finally, cardiologists discovered that she was suffering from heart failure due to a birth defect, called an atrial septal defect, that...

Lifespan Changes

In a sense, aging of the immune system actually begins before birth, when nonself T cells are selected for destruction, via programmed cell death (apoptosis), in the thymus. The immune system begins to decline early in life. The thymus gland reaches its maximal size in adolescence and then slowly shrinks. By age seventy, the thymus is one-tenth the size it was at the age of ten, and the immune system is only 25 as powerful. The declining strength of the immune response is why elderly people...

Liver Functions

Liver Hepatic Vessels

The liver carries on many important metabolic activities. Recall from chapter 13 (p. 532) that the liver plays a key role in carbohydrate metabolism by helping maintain the This transverse section of the abdomen reveals the liver and other organs within the upper portion of the abdominal cavity. This transverse section of the abdomen reveals the liver and other organs within the upper portion of the abdominal cavity. Inferior vena cava Coronary ligament Inferior vena cava Coronary ligament...

Macula Densa Function In Kidney

Juxtaglomerular Apparatus Consists

(a) Light micrograph of a section of the human renal cortex (220x). (b) Light micrograph of the renal medulla (80x micrograph enlarged to 200x). (a) Location of the juxtaglomerular apparatus. (b) Enlargement of a section of the juxtaglomerular apparatus, which consists of the macula densa (darker yellow) and the juxtaglomerular cells. Black arrows indicate direction of blood flow. Blue arrows indicate flow of glomerular filtrate and tubular fluid.

Critical Thinking Questions

What acidic and alkaline substances do you encounter in your everyday life What foods do you eat regularly that are acidic What alkaline foods do you eat 2. Using the information on page 51 to distinguish between saturated and unsaturated fats, try to list all of the sources of saturated and unsaturated fats you have eaten during the past twenty-four hours. 3. How would you reassure a patient who is about to undergo CT scanning for evaluation of a tumor, and who fears becoming a radiation...

Cpf

Calcification (kalsi-fi-ka-shun) Deposition of calcium salts in a tissue. p. 209 calcitonin (kalsi-to'-nin) Hormone secreted by the thyroid gland that helps regulate the level of blood calcium. p. 522 calorie (kal'o-re) A unit used to measure heat energy and the energy contents of foods. p. 745 calorimeter (kalo-rim'ei-ter) A device used to measure the heat energy content of foods bomb calorimeter. p. 746 canaliculus (kanah-lik'u-lus) Microscopic canals that connect the lacunae of bone tissue....

Ure 2325

Although many biological changes ensue as we grow older, photographs of actress Katharine Hepburn at various stages of her life indicate that we can age with great grace and beauty. Newborn begins to carry on respiration, obtain nutrients, digest nutrients, excrete wastes, regulate body temperature, and make circulatory adjustments Growth rate is high teeth begin to erupt muscular and nervous systems mature so that coordinated activities are possible communication begins Growth rate is high...

Reticular Formation

Scattered throughout the medulla oblongata, pons, and midbrain is a complex network of nerve fibers associated with tiny islands of gray matter. This network, the reticular formation (re-tik'u-lar for-ma'shun) or reticular activating system, extends from the superior portion of the spinal cord into the diencephalon (fig. 11.21). Its intricate system of nerve fibers connects centers of the hypothalamus, basal nuclei, cerebellum, and cerebrum with fibers in all the major ascending and descending...

Cheeks and Lips

Tissue Layers The Alimentary Canal

The cheeks form the lateral walls of the mouth. They consist of outer layers of skin, pads of subcutaneous fat, muscles associated with expression and chewing, and inner linings of moist, stratified squamous epithelium. Because cheek cells are easily removed, for many years biology laboratory classes have had students collect them and use them to study cell structure. More recently, similar cheekbrush tests have been developed to identify carriers of certain inherited disorders. The patient...

Control of Hormonal Secretions page 512

The concentration of each hormone in the body fluids is precisely regulated. a. Some endocrine glands secrete in response to nerve impulses. b. Other glands secrete hormones in response to releasing hormones the hypothalamus secretes. a. In a negative feedback system, a gland is sensitive to the concentration of a substance it regulates. b. When the concentration of the regulated substance reaches a certain concentration, it inhibits the gland. c. As the gland secretes less hormone, the...

Life Span Changes page 53

Endocrine glands tend to shrink and accumulate fibrous connective tissue, fat, and lipofuscin, but hormonal activities usually remain within the normal range. 1. GH levels even out, as muscular strength declines. 2. ADH levels increase due to slowed breakdown. 3. The thyroid shrinks but control of metabolism continues. 4. Decreasing levels of calcitonin and parathyroid hormone increase osteoporosis risk. 5. The adrenal glands show aging-related changes, but negative feedback maintains...

Gnrh Enters Blood Vessels In

Labium Minus

Production and secretion of male sex hormones Storage and maturation of sperm cells conveys sperm cells to vas deferens Conveys sperm cells to ejaculatory duct Secretes an alkaline fluid containing nutrients and prostaglandins fluid helps neutralize acidic semen Secretes an alkaline fluid that helps neutralize the acidic components of semen and enhances motility of sperm cells Secretes fluid that lubricates end of the penis Conveys urine and semen to outside of body inserted into the vagina...

Regulation of Metabolic Pathways

Enzyme Off Position

The rate at which a metabolic pathway functions is often determined by a regulatory enzyme responsible for one of its steps. This regulatory enzyme is present in limited quantity. Consequently, it can become saturated when the substrate concentration exceeds a certain level. Once this happens, increasing the substrate concentration no longer affects the reaction rate. In this way, a single enzyme can control a whole pathway. As a rule, such a rate-limiting enzyme is the first enzyme in a...

Divergence

Although a neuron has a single axon, axons may branch many times. Thus, impulses leaving a neuron of a neuronal pool may exhibit divergence di-ver'jens by reaching several other neurons. For example, one neuron may stimulate two others each of these, in turn, may stimulate several others, and so forth. Such a pattern of diverging axons can amplify an impulse that is, spread it to increasing numbers of neurons within the pool fig. 10.20b . As a result of divergence, an impulse originating from a...

Allergic Reactions

Both allergic reactions and immune responses entail sensitizing of lymphocytes or combining of antigens with antibodies. An allergic reaction, however, is an immune attack against a nonharmful substance, and can damage tissues. An allergy is also called a hypersensitivity reaction. One form of allergic reaction can occur in almost anyone, but another form affects only people who have inherited an ability to produce exaggerated immune responses. The antigens that trigger allergic responses are...

Closer Look at Cellular Respiration

Figure D.1 illustrates the chemical reactions of glycolysis. In the early steps of this metabolic pathway, the original glucose molecule is altered by the addition of phosphate groups phosphorylation and by the rearrangement of its atoms. ATP supplies the phosphate groups and the energy to drive these reactions. The result is a molecule of fructose bound to two phosphate groups fructose-1,6-bisphosphate . This molecule is split through two separate reactions into two 3-carbon molecules...

Middle Ear Blood Vessels

The tympanic membane is thought of as the boundary between the outer ear and the middle ear, but it is technically part of the middle ear. The middle ear includes the tympanic membrane, the tympanic cavity, and three small bones called auditory ossicles. The tympanic cavity is an air-filled space in the temporal bone that separates the external and internal ears. The tympanic membrane is a semitransparent membrane covered by a thin layer of skin on its outer surface and by mucous membrane on...

Connective Tissue Fibers

Fibroblasts produce three types of connective tissue fibers collagenous fibers, elastic fibers, and reticular fibers. Of these, collagenous and elastic fibers are the most abundant. Collagenous kol-lajce-nus fibers are thick threads of the protein collagen, which is the major structural protein of the body. Collagenous fibers are grouped in long, parallel bundles, and they are flexible but only slightly elastic fig. 5.16 . More importantly, they have great tensile strength that is, they can...

Tote Blood Vessels In

Capillary Network

Schematic representation of lymphatic vessels transporting fluid from interstitial spaces to the bloodstream. Schematic representation of lymphatic vessels transporting fluid from interstitial spaces to the bloodstream. Lymph capillaries are microscopic, closed-ended tubes that begin in the interstitial spaces of most tissues. The black arrows indicate blood flow while the white arrows indicate the flow of lymph. Shier-Butler-Lewis I IV. Transport I 16. Lymphatic System and I I The McGraw-Hill...

Ure 1542

Blood is carried to the lungs through branches of the pulmonary arteries, and it returns to the heart through pulmonary veins. 1. Slight net outflow of fluid from capillary 2. Solutes fail to enter alveoli but contribute to the osmotic pressure of the interstitial fluid 4. Fluid from the interstitial space enters lymphatic capillary or alveolar blood capillary 4. Fluid from the interstitial space enters lymphatic capillary or alveolar blood capillary 3. Any excess water in alveolus is drawn out...

Tools and Targets of Gene Therapy

Ada Deficiency Symptoms

Researchers use several methods to introduce therapeutic genes into cells. Healing DNA is given linked to viruses that have had their disease-causing genes removed in fatty bubbles called liposomes or complexed with other lipid molecules shot along with metal particles into cells and as naked preparations of DNA alone. The challenge in any nonheritable gene therapy is to target sufficient numbers of affected cells for a long enough time to exert a noticeable effect. A look at some specific gene...

Medulla Oblongata

The medulla oblongata is an enlarged continuation of the spinal cord, extending from the level of the foramen magnum to the pons see fig. 11.20 . Its dorsal surface flattens to form the floor of the fourth ventricle, and its ventral surface is marked by the corticospinal tracts, most of whose fibers cross over at this level. On each side of the medulla oblongata is an oval swelling called the olive, from which a large bundle of nerve fibers arises and passes to the cerebellum. Because of the...

Stretch Receptors

Blood Vessel Receptors

Stretch receptors are proprioceptors that send information to the spinal cord and brain concerning the lengths and tensions of muscles. The two main kinds of stretch receptors are muscle spindles and Golgi ten don organs however, no sensation results when they are stimulated. Muscle spindles are located in skeletal muscles near their junctions with tendons. Each spindle consists of one or more small, modified skeletal muscle fibers intrafusal fibers enclosed in a connective tissue sheath. Near...

Structure of the Wall

Blood Vessels Teeth

The wall of the alimentary canal consists of four distinct layers that are developed to different degrees from region to region. Although the four-layered structure persists throughout the alimentary canal, certain regions are specialized for particular functions. Beginning with the innermost tissues, these layers, shown in figure 17.3, include the following 1. Mucosa, or mucous membrane mu'kus mem'bran . This layer is formed of surface epithelium, underlying connective tissue lamina propria ,...

Sex Chromosomes and Their Genes

Sperm Blood Vessels

The X and Y chromosomes carry genes, but they are inherited in different patterns than are autosomal genes because of the different sex chromosome constitutions in males and females. Traits transmitted on the X chromosome are said to be X-linked, and on the Y, Y-linked. The X chromosome has more than one thousand genes the Y chromosome has only a few dozen genes. Y-linked genes are considered in three groups, based on their similarity to X-linked genes. One group consists of genes at the tips...

Inferior Vena Cava

Fetal Interrupted Inferior Vena Cava

Twenty-first through thirty-eighth week Body gains weight, subcutaneous fat deposited eyebrows and lashes appear eyelids reopen testes descend Size 21 inches 53 centimeters , weight 6 to 10 pounds 2.7 to 4.5 kilograms Blood flow from fetus, branch of umbilical artery Blood flow to fetus, branch of umbilical vein Oxygen and nutrients diffuse into the fetal blood from the maternal blood. Waste diffuses into the maternal blood from the fetal blood. Oxygen and nutrients into fetal blood Blood flow...

Cortisol

Cortisol hydrocortisone is a glucocorticoid, which means it affects glucose metabolism. It is produced in the middle zone zona fasciculata of the adrenal cortex and has a molecular structure similar to aldosterone fig. 13.30 . In addition to affecting glucose, cortisol influences protein and fat metabolism. Among the more important actions of cortisol are the following 1. It inhibits the synthesis of protein in various tissues, increasing blood concentration of amino acids. The set point of the...

Veins from the Abdominal and Thoracic Walls

Tributaries of the brachiocephalic and azygos veins drain the abdominal and thoracic walls. For example, the brachiocephalic vein receives blood from the internal thoracic vein, which generally drains the tissues the internal thoracic artery supplies. Some intercostal veins also empty into the brachiocephalic vein fig. 15.56 . The azygos az'i-gos vein originates in the dorsal abdominal wall and ascends through the mediastinum on the right side of the vertebral column to join the superior vena...

Movements of the Small Intestine

Like the stomach, the small intestine carries on mixing movements and peristalsis. The major mixing movement is called segmentation, in which small, ringlike contractions occur periodically, cutting the chyme into segments and moving it back and forth. Segmentation also slows the movement of chyme through the small intestine. Peristaltic waves propel chyme through the small intestine. These waves are usually weak, and they stop after pushing the chyme a short distance. Consequently, chyme moves...

Autonomic Neurotransmitters

The preganglionic fibers of the sympathetic and parasympathetic divisions all secrete acetylcholine, and for this reason they are called cholinergic kolin-er'jik fibers. The parasympathetic postganglionic fibers are also cholinergic fibers. Most sympathetic postganglionic fibers, however, secrete norepinephrine noradrenalin and are called adrenergic adren-er'jik fibers see fig. 11.41 . Exceptions to this include the sympathetic postganglionic fibers that stimulate sweat glands and a few...

Cranial Nerves

Nerf Lacrymal

Twelve pairs of cranial nerves arise from the underside of the brain. Except for the first pair, which begins within the cerebrum, these nerves originate from the brain stem. They pass from their sites of origin through foramina of the skull and lead to areas of the head, neck, and trunk. Although most cranial nerves are mixed nerves, some of those associated with special senses, such as smell and vision, contain only sensory fibers. Others that innervate muscles and glands are primarily...

Feces

Feces fe'sez are composed of materials that were not digested or absorbed, with water, electrolytes, mucus, and bacteria. Usually the feces are about 75 water, and their color derives from bile pigments altered by bacterial action. The pungent odor of the feces results from a variety of compounds that bacteria produce. These compounds include phenol, hydrogen sulfide, indole, skatole, and ammonia. Clinical Application 17.5 examines conditions affecting the large intestine. 99 How does...

M

Macromineral mak'ro-miner-al An inorganic substance that is necessary for metabolism and is one of a group that accounts for 75 of the mineral elements within the body major mineral. p. 757 macromolecule mak'ro-mol'e-kul A very large molecule. p. 9 macrophage mak'ro-faj A large phagocytic cell. p. 151 macula mak'u-lah A group of hair cells and supporting cells associated with an organ of static equilibrium. p. 475 macula lutea mak'u-lah lu'te-ah A yellowish depression in the retina of the eye...

Mm M

Seminal Vessels Prostate

Crossing-over mixes up traits. a Pairing of homologous chromosomes, b chromatids crossing over, c results of crossing-over. The different colors represent the fact that one homologous chromosome comes from the individual's father and one from the mother. 2. Metaphase I. During the first metaphase, chromosome pairs line up about midway between the poles of the developing spindle, and they are held under great tension, like two groups of people playing tug-of-war. Each chromosome pair consists of...

Flexors

Cross Section Medial Forearm

The flexor carpi radialis flek'sor kar-pi'rade-a'lis is a fleshy muscle that runs medially on the anterior side of the forearm. It extends from the distal end of the humerus into the hand, where it is attached to metacarpal bones. The flexor carpi radialis flexes and abducts the hand at the wrist fig. 9.30 . The flexor carpi ulnaris flek'sor kar-pi' ul-na'ris is located along the medial border of the forearm. It con nects the distal end of the humerus and the proximal end of the ulna to carpal...

Cellular Respiration

Blood Vessels Figures

Cellular respiration occurs in three distinct, yet interconnected, series of reactions glycolysis gli-kol' i-sis , the citric acid cycle, and the electron transport chain oxidative phosphorylation fig. 4.6 . The products of these reactions include CO2, water, and energy. Although most of the energy is lost as heat, almost half is captured in a form that the cell can use through the synthesis of ATP adenosine triphosphate , an energy-rich molecule. Cellular respiration includes aerobic reactions...

Plasma Proteins

By weight, plasma proteins are the most abundant dissolved substances solutes in plasma. These proteins remain in the blood and interstitial fluids and ordinarily are not used as energy sources. The three main plasma protein groups are albumins, globulins, and fibrinogen. The groups differ in chemical composition and physiological function. Albumins al-bu'minz are the smallest of the plasma proteins, yet account for 60 of these proteins by weight. They are synthesized in the liver, and because...

Obstruction of Lymph Movement

The continuous movement of fluid from interstitial spaces into blood capillaries and lymphatic capillaries stabilizes the volume of fluid in these spaces. Conditions that interfere with lymph movement cause tissue fluid to accumulate within the interstitial spaces, producing edema. For example, surgery to remove a cancerous breast tumor also usually removes nearby axillary lymph nodes, because associated lymphatic vessels can transport cancer cells to other sites metastasis . Removing the...

Transplantation and Tissue Rejection

Immune Suppressing Drugs For Transplants

When a car breaks down, replacing the damaged or malfunctioning part often fixes the trouble. The same is sometimes true for the human body. Transplanted tissues and organs include corneas, kidneys, lungs, pancreases, bone marrow, pieces of skin, livers, and hearts. The danger the immune system poses to transplanted tissue is that the recipient's cells may recognize the donor's tissues as foreign and attempt to destroy the transplanted tissue. Such a response is called a tissue rejection reac...

Major Cell Types

Connective tissues contain a variety of cell types. Some of them are called fixed cells because they are usually present in stable numbers. These include fibroblasts and mast cells. Other cells, such as macrophages, are wandering cells. They temporarily appear in tissues, usually in response to an injury or infection. The fibroblast ficbro-blast is the most common kind of fixed cell in connective tissues. It is a large, star-shaped cell. Fibroblasts produce fibers by secreting protein into the...

Electrolyte and Acid Base Balance

Dehydration removal of water from the cells or body fluids. edem-, swelling edema swelling due to an abnormal accumulation of extracellular fluid. -emia, a blood condition hypoproteinemia abnormally low concentration of blood plasma protein. extra-, outside extracellular fluid fluid outside of the body cells. im- or in- , not imbalance condition in which factors are not in equilibrium. intra-, within intracellular fluid fluid within the body cells. neutr-, neither one nor the other neutral...

RNA Molecules

Rna Molecule Base

RNA ribonucleic acid molecules differ from DNA molecules in several ways. RNA molecules are single- stranded, and their nucleotides contain ribose rather than deoxyribose sugar. Like DNA, RNA nucleotides each contain one of four organic bases, but whereas adenine, cytosine, and guanine nucleotides occur in both DNA and RNA, thymine nucleotides are found only in DNA. In place of thymine nucleotides, RNA molecules contain uracil U nucleotides fig. 4.21 and Appendix D, A Closer Look at Cellular...

Diencephalon

The diencephalon dien-sef'ah-lon develops from the posterior forebrain and is located between the cerebral hemispheres and above the brain stem see figs. 11.15 and 11.20 . It surrounds the third ventricle and is largely composed of gray matter. Within the diencephalon, a dense mass, called the thalamus thal'ah-mus , bulges into the third ventricle from each side. Another region of the diencephalon that includes many nuclei is the hypothalamus hipo-thal'ah-mus . It lies below the thalamic nuclei...

Characteristics of Venous Pathways

The vessels of the venous system begin with the merging of capillaries into venules, venules into small veins, and small veins into larger ones. Unlike the arterial pathways, however, those of the venous system are difficult to follow. This is because the vessels commonly connect in irregular networks, so many unnamed tributaries may join to form a relatively large vein. On the other hand, the larger veins typically parallel the courses of named arteries, and these veins often have the same...

Prevention of Coagulation

In a healthy cardiovascular system, the endothelium of the blood vessels partly prevents spontaneous blood clot formation. This smooth lining discourages the accumulation of platelets and clotting factors. Endothe-lial cells also produce a prostaglandin see chapter 13, p. 512 called prostacyclin PGI2 , which inhibits the adherence of platelets to the inner surface of healthy blood vessel walls. When a clot is forming, fibrin threads latch onto or adsorb thrombin, thus helping prevent the spread...

Pain Nerve Pathways

The nerve fibers that conduct impulses away from pain receptors are of two main types acute pain fibers and chronic pain fibers. The acute pain fibers also known as A-delta fibers are thin, myelinated nerve fibers. They conduct nerve impulses rapidly, at velocities up to 30 meters per second. These impulses are associated with the sensation of sharp pain, which typically seems to originate in a local area of skin. This type of pain seldom continues after the pain-producing stimulus stops. The...

It

Perpendicular Plate Ethmoid

Nasal bone Lacrimal bone Ethmoid bone Nasal bone Lacrimal bone Ethmoid bone External auditory meatus Zygomatic arch External auditory meatus Zygomatic arch The skull, left posterolateral view. Palatine process of maxilla Palatine bone Greater palatine foramen Base of the skull, sphenoidal region. Foramen ovale Foramen spinosum Foramen lacerum Carotid canal Jugular foramen Base of the skull, occipital region. Foramen ovale Foramen spinosum Foramen lacerum Carotid canal Jugular foramen...

Blood Vessels In Ear Canal

Semicircular Canals

The inner ear is a complex system of intercommunicating chambers and tubes called a labyrinth lab'i-rinth . Each ear has two such regions the osseous labyrinth and the membranous labyrinth. The osseous labyrinth is a bony canal in the temporal bone the membranous labyrinth is a tube that lies within the osseous labyrinth and has a similar shape fig. 12.12a . Between the osseous and membranous labyrinths is a fluid called perilymph, which cells in the wall of the bony canal secrete. Within the...

Light Refraction

When a person sees something, either the object is giving off light, or light waves are reflected from it. These light waves enter the eye, and an image of what is seen focuses upon the retina. The light rays must bend to be focused, a phenomenon called refraction re-frak'shun . Refraction occurs when light waves pass at an oblique angle from a medium of one optical density into a medium of a different optical density. For example, as figure 12.36 shows, when light passes obliquely from a less...

Sense of Taste

Blood Vessels The Chin

Taste buds are the special organs of taste. They resemble orange sections and are primarily located on the surface of the tongue where they are associated with tiny elevations called papillae figs. 12.8 and 12.9 . Taste buds are also scattered in the roof of the mouth, the linings of the cheeks, and the walls of the pharynx. a Taste buds on the surface of the tongue are associated with nipplelike elevations called papillae. b A taste bud contains taste cells and has an opening, the taste pore,...

Simple Cuboidal Epithelium

Tightly Packed Basement Pics

Simple cuboidal epithelium consists of a single layer of cube-shaped cells. These cells usually have centrally located, spherical nuclei fig. 5.2 . Simple cuboidal epithelium covers the ovaries and lines the kidney tubules and ducts of certain glands, One of the ways that cancer cells spread is by secreting a substance that dissolves basement membranes. This enables cancer cells to invade adjacent tissue layers. Cancer cells also produce fewer adhesion proteins, or none at all, which allows...

Superior Illiac Spine

Illiac Crest Blood Vessels

a Anterior view and b posterior view of the pelvic girdle. This girdle provides an attachment for the lower limbs and together with the sacrum and coccyx forms the pelvis. c Radiograph of the pelvic girdle. a Medial surface of the left coxa. b Lateral view. a Medial surface of the left coxa. b Lateral view. The female pelvis is usually wider in all diameters and roomier than that of the male. a Female pelvis. b Male pelvis. The female pelvis is usually wider in all diameters and roomier than...

Palate

Lingual Tonsil Saggital View

The palate forms the roof of the oral cavity and consists of a hard anterior part and a soft posterior part. The hard palate is formed by the palatine processes of the maxillary bones in front and the horizontal portions of the palatine bones in back. The soft palate forms a muscular arch, which extends posteriorly and downward as a cone-shaped projection called the uvula. During swallowing, muscles draw the soft palate and the uvula upward. This action closes the opening between the nasal...

Regulation of Pain Impulses

Awareness of pain occurs when pain impulses reach the level of the thalamus that is, even before they reach the cerebral cortex. However, the cerebral cortex must judge the intensity of pain and locate its source. The cerebral cortex is also responsible for emotional and motor responses to pain. C gt 0 Reconnect to chapter 10, Postsynaptic Potentials, page 380 Still other parts of the brain, including areas of gray matter in the midbrain, pons, and medulla oblongata, regulate the flow of pain...

Clinical Terms Related to the Lymphatic System and Immunity

Asplenia ah-sple'ne-ah Absence of a spleen. immunocompetence imu-no-kom'pe-tens Ability to produce an immune response to the presence of antigens. immunodeficiency imu-no-de-fish'en-se Inability to produce an immune response. lymphadenectomy lim-fade-nek'to-me Surgical removal of lymph nodes. lymphadenopathy lim-fade-nop'ah-the Enlargement of the lymph nodes. lymphadenotomy lim-fade-not'o-me Incision of a lymph node. lymphocytopenia limfo-sito-pe'ne-ah Too few lymphocytes in the blood....

Auditory Nerve Pathways

Equilibrium Pathway Ear

The cochlear branches of the vestibulocochlear nerves enter the auditory nerve pathways that extend into the medulla oblongata and proceed through the midbrain to the thalamus. From there they pass into the auditory cortices of the temporal lobes of the cerebrum, where they are interpreted. On the way, some of these fibers cross over, so that impulses arising from each ear are interpreted on both sides of the brain. Consequently, damage to a temporal lobe on one side of the brain is not...