By Y. Jesper. The College of Metaphysical Studies.
Feel it contracting beneath your skin and note motor units within a muscle purchase malegra fxt 140 mg line loss of erectile dysfunction causes, the secretion of epinephrine (ep'ı˘- the movement that occurs at the joint generic 140 mg malegra fxt with amex erectile dysfunction at age 27. Shape: rhomboideus (like a rhomboid); trapezius (like a testes, and ovaries. Because they are soluble in lipids, they readily pass through cell membranes and enter the cytoplasm, trapezoid); or denoting the number of heads of origin: tri- where they combine with proteins to form steroid-protein complexes ceps (three heads), biceps (two heads) that are necessary for the syntheses of specific kinds of messenger RNA molecules. Location: pectoralis (in the chest, or pectus); intercostal mote weight gain in cancer and anorexic patients. It soon became (between ribs); brachia (arm) apparent, however, that steroids taken by bodybuilders and ath- 3. Attachment: many facial muscles (zygomaticus, tempo- letes could provide them with increased muscle mass, strength, and aggressiveness. The use of steroids is now considered illegal ralis, nasalis); sternocleidomastoid (sternum, clavicle, and by most athletic associations. Not only do they confer unfair advan- mastoid process of the temporal bone) Van De Graaff: Human IV. Muscular System © The McGraw−Hill Anatomy, Sixth Edition Companies, 2001 Chapter 9 Muscular System 247 Motor neuron axon Axon terminals Muscle fiber nucleus Motor end plate Myofibril of muscle fiber Mitochondria Synaptic vesicles Neuromuscular cleft Folded sarcolemma Motor end plate Waldrop (a) Axon Motor end plate Muscle fiber (b) FIGURE 9. The motor end plate is the specialized portion of the sarcolemma of a muscle fiber surrounding the terminal end of the axon. A motor neuron and the skeletal muscle fibers it innervates constitute a motor unit. Size: maximus (larger, largest); minimus (smaller, small- est); longus (long); brevis (short) Knowledge Check 5. Relative position: lateral, medial, internal, and external gluteal, perineal, brachial, antebrachial, inguinal, thigh, and popliteal. Function: adductor, flexor, extensor, pronator, and leva- tor (lifter) 13. Refer to chapter 8 and review the movements permitted at synovial joints. Muscular System © The McGraw−Hill Anatomy, Sixth Edition Companies, 2001 Developmental Exposition The Muscular System (a) EXPLANATION The formation of skeletal muscle tissue begins during the fourth weekof embryonic development as specialized mesodermal cells called myoblasts begin rapid mitotic division (exhibit I). The pro- (b) liferation of new cells continues while the myoblasts migrate and fuse together into syncytial myotubes. The process of muscle fiber development occurs within specialized mesodermal masses called myotomes in the embryonic trunk area and from loosely organized masses of mesoderm in the head and appendage areas. At 6 weeks, the trunk of an embryo is segmented into distinct myotomes (exhibit II) that are associated (d) dorsally with specific sclerotomes—paired masses of mesenchymal tissue that give rise to vertebrae and ribs. As will be explained in chapter 12, spinal nerves arise from the spinal cord and exit be- tween vertebrae to innervate developing muscles in the adjacent myotomes. As myotomes develop, additional myoblasts migrate ventrally, toward the midline of the body, or distally, into the de- (e) veloping limbs. The muscles of the entire muscular system have been differentiated and correctly positioned by the eighth week. The orientation of the developing muscles is preceded and influ- enced by cartilaginous models of bones. It is not certain when skeletal muscle is sufficiently devel- oped to sustain contractions, but by week 17 the fetal movements known as quickening are strong enough to be recognized by the mother. The individual muscle fibers have now thickened, the nuclei have moved peripherally, and the filaments (myofila- ments) can be recognized as alternating dark and light bands. Shortly before a baby is born, the formation of myoblast cells ceases, and all of the muscle cells have been determined. Differ- ences in strength, endurance, and coordination are somewhat ge- netically determined but are primarily the result of individual body conditioning. Muscle coordination is an ongoing process of achieving a fine neural control of muscle fibers. Although inner- vation and muscle contraction occur early during fetal development, EXHIBIT I The development of skeletal muscle fibers. Myotubes grow in length by incorporating addi- tional myoblasts; each adds an additional nucleus. Muscular System © The McGraw−Hill Anatomy, Sixth Edition Companies, 2001 EXHIBIT II The development of skeletal muscles. Segmental myotomes give rise to the muscles of the trunk area and girdles.
Generally speaking order 140 mg malegra fxt overnight delivery erectile dysfunction treatment chinese medicine, the thinner the UV light generic 140mg malegra fxt amex erectile dysfunction age 50, necessary for synthesis of vitamin D, are absorbed read- skin, the greater the sensitivity. Of clinical consideration is the fact that certain chemicals such as lipid-soluble toxins and pesticides can easily enter the body through the skin. Communication Humans are highly social animals, and the integument plays Synthesis an important role in communication. Various emotions, such The integumentary system synthesizes melanin and keratin, which as anger or embarrassment, may be reflected in changes of remain in the skin synthesis of vitamin D, which is used elsewhere skin color. The contraction of specific facial muscles pro- in the body and begins in the skin with activation of a precursor duces facial expressions that convey an array of emotions, in- molecule by UV light. The molecule is modified in the liver and cluding love, surprise, happiness, sadness, and despair. Only small amounts of UV light are necessary for vita- frequently elicit subconscious responses from others who de- min D synthesis, but these amounts are very important to a grow- tect them. Active vitamin D enters the blood and helps regulate the metabolism of calcium and phosphorus, which are important Knowledge Check in the development of strong and healthy bones. List five modifications of the integument that are struc- turally or functionally protective. Explain how the integument functions to regulate body flu- Sensory Reception ids and temperature. Integumentary System © The McGraw−Hill Anatomy, Sixth Edition Companies, 2001 Chapter 5 Integumentary System 115 EPIDERMAL DERIVATIVES Hair, nails, and integumentary glands form from the epidermal layer, and are therefore of ectodermal derivation. Hair and nails are structural features of the integument and have a limited func- tional role. By contrast, integumentary glands are extremely im- portant in body defense and maintenance of homeostasis. Objective 6 Describe the structure of hair and list the three principal types. Objective 8 Compare and contrast the structure and function of the three principal kinds of integumentary glands. Humans are relatively hairless, with only the scalp, face, pubis, and axillae being densely haired. Men and women have about the same density of hair on their bodies, but hair is generally more obvious on men (fig. Certain structures and regions of the body are hairless, such as the palms, soles, lips, nip- ples, penis, and parts of the female genitalia. It may be a genetic expres- sion, as in certain ethnic groups, or occur as the result of a metabolic disorder, usually endocrine. Hirsutism occurs in some women as they experience hormonal changes during menopause. Various treat- ments for hirsutism include hormonal injections and electrolysis to permanently destroy selected hair follicles. The eyelashes and the hair in the nostrils protect against airborne particles. Some secondary functions The life span of a hair varies from 3 to 4 months for an eye- of hair are to distinguish individuals and to serve as a sexual lash to 3 to 4 years for a scalp hair. The shaft is the visible, but dead, portion of sults when hair is lost and not replaced. This condition may be the hair projecting above the surface of the skin. The bulb is the disease-related, but it is generally inherited and most frequently enlarged base of the root within the hair follicle. As the treatment is effective in reversing genetic baldness; however, cells divide, they are pushed away from the nutrient supply to- flaps or plugs of skin containing healthy follicles from hairy parts ward the surface, and cellular death and keratinization occur. Integumentary System © The McGraw−Hill Anatomy, Sixth Edition Companies, 2001 116 Unit 4 Support and Movement (a) (b) FIGURE 5. A cuticle covers the cortex and forms the toughened outer of hair is determined by the cross-sectional shape: straight hair is layer of the hair. Cells of the cuticle have serrated edges that give round in cross section, wavy hair is oval, and kinky hair is flat. Sebaceous glands and arrectores pilorum muscles (de- scribed previously) are attached to the hair follicle (fig. People exposed to heavy metals, such as lead, mercury, ar- senic, or cadmium, will have concentrations of these metals The arrectores pilorum muscles are involuntary, responding to in their hair that are 10 times as great as those found in their blood thermal or psychological stimuli.
The olfactory bulbs tory hairs to the cerebral cortex generic malegra fxt 140 mg amex erectile dysfunction watermelon,where interpretation occurs discount malegra fxt 140mg with visa erectile dysfunction doctor mn. Within the olfactory bulb, neurons of the olfactory nerves synapse with dendrites of neu- rons forming the olfactory tract. Sensory impulses are conveyed GUSTATORY SENSE along the olfactory tract and into the olfactory portion of the cerebral cortex,where they are interpreted as odor and cause the Taste receptors are specialized epithelial cells, clustered together perception of smell. Only about 2% of inhaled air comes in contact with the olfac- Objective 10 Identify the cranial nerves and the sensory tory receptors, which are positioned in the nasal mucosa pathways of gustation. Olfactory sensitivity can be increased by forceful sniffing, which draws the air into con- tact with the receptors. Taste Certain chemicals activate the trigeminal nerves (V) as well buds are specialized sensory organs that are most numerous on the as the olfactory nerves (I) and cause reactions. Pepper, for example, surface of the tongue,but they are also present on the soft palate may cause sneezing; onions cause the eyes to water; and smelling and on the walls of the oropharynx. The cylindrical taste bud is salts (ammonium salts) initiate respiratory reflexes and are used to revive unconscious persons. However, because of the caustic nature composed of numerous sensory gustatory cells that are encapsu- of smelling salts and the irreparable damage it may cause to the un- myelinated olfactory hairs, it is seldom used in first aid treatment of an unconscious person. Sensory Organs © The McGraw−Hill Anatomy, Sixth Edition Coordination Companies, 2001 Chapter 15 Sensory Organs 497 Vallate papilla Filiform papilla Lingual tonsil Epiglottis Fungiform papilla Palatine tonsil Root of tongue Vallate Taste buds Body papillae of tongue (b) Fungiform papillae Squamous Median epithelium groove of tongue Supporting cell Apex Filiform of tongue (a) papillae Gustatory cell Taste pore Gustatory microvilli Connective tissue (c) FIGURE 15. Each gustatory cell contains Taste buds are found only in the vallate and fungiform papil- a dendritic ending called a gustatory microvillus that projects to lae. The filiform papillae, although the most numerous of the the surface through an opening in the taste bud called the taste human tongue papillae, are not involved in the perception of taste. The gustatory microvilli are the sensitive portion of the re- Their outer cell layers are continuously converted into scalelike pro- ceptor cells. Saliva provides the moistened environment neces- jections, which give the tongue surface its somewhat abrasive feel. There are only four basic tastes,which are sensed most Taste buds are elevated by surrounding connective tissue acutely on particular parts of the tongue (fig. Three princi- sweet (tip of tongue), sour (sides of tongue), bitter (back of pal types of papillae can be identified: tongue),and salty (over most of the tongue,but concentrated • Vallate papillae. Sensory Organs © The McGraw−Hill Anatomy, Sixth Edition Coordination Companies, 2001 498 Unit 5 Integration and Coordination Sweet Sour Salty Bitter receptors receptors receptors receptors FIGURE 15. This diagram indicates the tongue regions that are maximally sensitive to different tastes. Trigeminal nerve Trigeminal ganglion Geniculate ganglion Lingual nerve Facial nerve Uvula Tongue Glossopharyngeal nerve Chorda tympani nerve Vagus nerve Laryngeal nerve FIGURE 15. The chorda tympani nerve is the sensory branch of the facial nerve innervating the tongue. Branches from the paired vagus (tenth cranial) nerves and the trigeminal (fifth cranial) nerves also provide some sensory innervation. The hypoglossal (twelfth cranial) nerve (not shown) provides motor innervation to the tongue. The lingual nerve transmits general sensory information from the tongue (hot, cold, pressure, and pain). Sensory Organs © The McGraw−Hill Anatomy, Sixth Edition Coordination Companies, 2001 Chapter 15 Sensory Organs 499 The sensory pathway that relays taste sensations to the brain mainly involves two paired cranial nerves (fig. Taste sensations passing through the nerves just Principal Functions Principal Functions mentioned are conveyed through the medulla oblongata and thalamus to the parietal lobe of the cerebral cortex, where they Eyelid: protection Lens cap: protection are interpreted. Conjunctiva: protection Lens filter: protection Cornea and lens: focus incoming Lens system: focuses incoming light Because taste and smell are both chemoreceptors, they com- light waves waves plement each other. We often confuse a substance’s smell with its taste; and if we have a head cold or hold our nose while eat- Iris and pupil: regulate amount of Variable aperture system: regulates ing, food seems to lose its flavor. Distinguish between papillae, taste buds, and gustatory mi- Pigment epithelium: maintains Black interior of camera: maintains crovilli. Which cranial nerves have sensory innervation associated Retina: contains photosensitive Film: material coated on one side with taste? What are the sensory pathways to the brain cones and rods that respond to with photosensitive emulsion where the perception of taste occurs? Formation of the sensory components of the eye is com- sider, for example, the extremely keen eyesight of a hawk, which plete at 20 weeks, and the accessory structures have been soars high in the sky searching for food, or the eyesight of the owl, formed by 32 weeks. Predatory species, such as cats, Objective 11 Describe the accessory structures of the eye have eyes that are directed forward, allowing depth perception.
If the output drops to less than 30 cc per hour generic 140 mg malegra fxt free shipping erectile dysfunction 38 years old, it may patient’s own peritoneal membranes for filtering buy malegra fxt 140 mg overnight delivery erectile dysfunction caused by spinal stenosis. Dialysis fluid is indicate renal failure—the loss of the kidney’s ability to introduced into the peritoneal cavity, and then, after a period of maintain fluid and electrolyte balance and to excrete waste time, discarded after wastes have accumulated. Acute called continuous ambulatory peritoneal dialysis (CAPD), can be renal failure is the sudden loss of kidney function caused by performed several times a day by the patients themselves on an shock and hemorrhage, thrombosis, or other physical trauma outpatient basis. Urinary System © The McGraw−Hill Anatomy, Sixth Edition Body Companies, 2001 694 Unit 6 Maintenance of the Body Urinary Incontinence The inability to voluntarily retain urine in the urinary bladder is Clinical Case Study Answer known as urinary incontinence. It has a number of causes and may The hematuria experienced by the patient is probably the result of lacer- be temporary or permanent. Emotional stress is a cause of tempo- ation caused by the upper abdominal knife wound. Permanent incontinence may result quadrant stab most likely did not violate the urinary tract. The course of blood seen in the catheter begins and proceeds as follows: abdominal from neurological trauma, various urinary diseases, tissue damage aorta → right renal artery → smaller parenchymal artery → through the within the urinary bladder or urethra, or weakness of the pelvic lacerated vessel(s) → into the lacerated urinary collecting system, either floor muscles. Remarkable advances have been made in treating at the calyx or the renal pelvis or proximal right ureter → urinary blad- permanent urinary incontinence through the implantation of an der → into catheter. During the operation, the surgeon should keep in artificial urethral sphincter. If, therefore, she is prompted to remove the damaged kidney, she should first confirm the presence of a second functioning kidney. If a second kidney is not present, every effort should be made to correct the prob- lem without performing a nephrectomy, which would consign the pa- tient to chronic hemodialysis or kidney transplant. A routine urinalysis reveals red blood cells too numerous to count, no white blood cells, and no bacte- ria. You order an intravenous urogram (IVU) (a), which is an injection of intravenous con- trast material for an exam of the urinary sys- tem, and CT scan (b). What is the large dark mass (filling defect) seen in the urinary bladder (indicated with the letter B) on the IVU? On the CT, white contrast fills the lumen of the urinary bladder (indicated with an arrow). Synchronous tumors are tumors of the (a) same cell type occuring at the same time in separate locations. Urinary System © The McGraw−Hill Anatomy, Sixth Edition Body Companies, 2001 Chapter 19 Urinary System 695 CLINICAL PRACTICUM 19. She describes the pain as intermittent and crampy, but de- nies any fever or blood in her urine. Physical exam shows a nontender ab- domen and no evidence of costovertebral angle tenderness. Routine urinalysis shows minimal red blood cells, no white blood cells, and no bacteria. What effect does this have on the ureter as demonstrated by the postcontrast image? Precontrast image Postcontrast image Chapter Summary Introduction to the Urinary System 3. The end product of the deliver blood to peritubular capillaries which is folded into rugae. These urinary system is urine, which is voided surrounding the nephron tubules. Each kidney is contained by a renal tubules are drained into papillary during ejaculation. The female capsule and divided into an outer renal ducts that extend through the renal urethra is much shorter than that of a cortex and an inner renal medulla. Micturition is controlled by reflex centers the minor calyces and then into the major calyces, which drain into the 1. Urine is channeled from the kidneys to in the second, third, and fourth sacral renal pelvis. From there, urine flows the urinary bladder by the ureters and segments of the spinal cord.
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