By X. Gnar. Grace University. 2018.
In this zone generic viagra plus 400mg amex impotence forum, heat balance corresponding to evaporation of about 13 to 15 g/(m h) buy 400mg viagra plus erectile dysfunction hiv medications, is maintained entirely by controlling conductance and Tsk of which about half is moisture lost in breathing and half is 536 PART VIII TEMPERATURE REGULATION AND EXERCISE PHYSIOLOGY insensible perspiration. This evaporation occurs independ- temperature until it reaches the skin, reaches skin tempera- ent of thermoregulatory control. As the ambient tempera- ture as it passes through the skin, and then stays at skin ture increases, the body depends more and more on the temperature until it returns to the core, we can compute the evaporation of sweat to achieve heat balance. Eccrine sweat is essentially a dilute electrolyte rather than the usual L/min to simplify computing HF in W solution, but apocrine sweat also contains fatty material. Conductance as a result of con- ulations, are more important in human thermoregulation vection by the blood (Cb) is calculated as: and number about 2,500,000. A healthy man Of course, heat continues to flow by conduction unacclimatized to heat can secrete up to 1. Total glands can change, especially with endurance exercise heat flow is given by training and heat acclimatization; men well acclimatized to HF (Cb C0) (Tc Tsk) (10) heat can attain peak sweat rates greater than 2. Such rates cannot be maintained, however; the maximum daily in which C0 is thermal conductance of the tissues when skin sweat output is probably about 15 L. In producing sweat that is hypotonic to plasma, what artificial and represent the conditions for maximum the glands reabsorb sodium from the sweat duct by active efficiency of heat transfer by the blood. As sweat rate increases, the rate at which the exchanges heat also with the tissues through which it glands reabsorb sodium increases more slowly, so that passes on its way to and from the skin. The sodium these other tissues is greatest when skin blood flow is low; concentration of sweat is affected also by heat acclimatiza- in such cases, heat flow to the skin may be much less than tion and by the action of mineralocorticoids. How- ever, equation 8 is a reasonable approximation in a warm subject with moderate to high skin blood flow. Although Skin Circulation Is Important in Heat Transfer measuring whole-body SkBF directly is not possible, it is believed to reach several liters per minute during heavy ex- Heat produced in the body must be delivered to the skin ercise in the heat. Therefore, even a moderate rate of skin blood flow can ment, Tsk may easily be low enough for this to occur. If the rate of heat production were increased to control dry (convective and radiative) heat loss by varying 480 W by moderate exercise, the temperature difference skin blood flow and, thus, skin temperature. Once sweating between core and skin would have to rise to 30 C—and begins, skin blood flow continues to increase as the person core temperature to well beyond lethal levels—to allow all becomes warmer. In these conditions, however, the ten- the heat produced to be conducted to the skin. In the latter dency of an increase in skin blood flow to warm the skin is circumstances, the conductance of the shell must increase approximately balanced by the tendency of an increase in greatly for the body to reestablish thermal balance and sweating to cool the skin. This is accomplished gun, further increases in skin blood flow usually cause little by increasing the skin blood flow. Skin blood flow and sweating suming that blood on its way to the skin remains at core work in tandem to dissipate heat under such conditions. CHAPTER 29 The Regulation of Body Temperature 537 Sympathetic Control of Skin Circulation. Blood flow in through the use of shelter, space heating, air conditioning, human skin is under dual vasomotor control. In most of the and clothing—enables humans to live in the most extreme skin, the vasodilation that occurs during heat exposure de- climates in the world, but it does not provide fine control pends on sympathetic nerve signals that cause the blood of body heat balance. In contrast, physiological ther- vessels to dilate, and this vasodilation can be prevented or moregulation is capable of fairly precise adjustments of reversed by regional nerve block. Because it depends on the heat balance but is effective only within a relatively narrow action of nerve signals, such vasodilation is sometimes re- range of environmental temperatures. Active vasodilation occurs in almost all the skin, except in so-called acral regions— Behavioral Thermoregulation Is Governed hands, feet, lips, ears, and nose. In skin areas where active by Thermal Sensation and Comfort vasodilation occurs, vasoconstrictor activity is minimal at thermoneutral temperatures, and active vasodilation during Sensory information about body temperatures is an essen- heat exposure does not begin until close to the onset of tial part of both behavioral and physiological thermoregu- sweating. The distinguishing feature of behavioral thermoreg- much affected by small temperature changes within the ulation is the involvement of consciously directed efforts to thermoneutral range. Thermal discomfort provides The neurotransmitter or other vasoactive substance re- the necessary motivation for thermoregulatory behavior, sponsible for active vasodilation in human skin has not and behavioral thermoregulation acts to reduce both the been identified. Active vasodilation operates in tandem discomfort and the physiological strain imposed by a with sweating in the heat, and is impaired or absent in an- stressful thermal environment.
Interferons and glatiramer acetate should be started early in the disease because they do all of the following except: a 400 mg viagra plus visa erectile dysfunction and causes. Which of the following complications should a nurse caring for a patient with advanced MS be alert to? As part of continuing care for patients with relapsing-remitting MS who have experienced a relapse trusted 400 mg viagra plus impotence nitric oxide, the nurse will need to do all of the following except: a. Emphasize the importance of continuing treatment CHAPTER 22: CERTIFICATION STUDY QUESTIONS 115 b. Help the patient to establish realistic expectations of the drug therapy 12. Which of the following statements about the role of MS nurses is not correct? Cost containment pressures brought about a dramatic and ongoing expansion in the role of the nurse b. The MS nurse provides primary, acute, specialized, and reha- bilitative care for patients with multiple sclerosis d. Nurses provide education, support, and healthcare delivery for patients and their families 13. All of the following characterize the aims of nursing research except: a. Nurses who wish to conduct research can begin to seek funding and support by: a. The recent development of a cure for MS has brought hope to patients and their families 16. Which of the following statements about the pathophysiology of MS is true? The lesions associated with MS are particularly prevalent in the optic nerves and the gray matter of the spinal cord, brain- stem, cerebellum, and cerebrum b. Loss of the myelin sheath disrupts electrical conduction with- in the CNS c. Myelin loss occurs only in the spinal cords of people with MS 116 NURSING PRACTICE IN MULTIPLE SCLEROSIS: A CORE CURRICULUM 17. People with MS frequently experience neurologic deficits such as tremor, sensory loss, and bladder incontinence b. Secondary symptoms of MS include bladder infections and pressure sores c. Neurologic signs and symptoms associated with MS are dependent on the location of the lesions in the CNS 18. In approximately 85% of people with MS, the course is described as relapsing-remitting at the time of diagnosis d. The course of MS is invariably characterized by progressive deterioration 19. Four disease-modifying agents have been approved in relaps- ing-remitting MS b. Glatiramer acetate’s mode of action involves inhibition of the immune response to myelin basic protein and other myelin antigens d. Adherence to medications is independent of sex, age, and other demographics b. Information should imply that there is no real risk associated with MS with or without treatment c. Healthcare professionals should always be in charge of mak- ing decisions about treatment d. People who think that their disease is not under their control adhere more readily to treatment 21. You are caring for a patient with relapsing-remitting MS who has just started treatment with interferon therapy. Interferon reduces the frequency of exacerbations but does not restore function b. Interferon can be associated with unpleasant side effects but these must be weighed against potential benefits CHAPTER 22: CERTIFICATION STUDY QUESTIONS 117 d. Which of the following is not generally considered a barrier to adherence?
Fructose is taken up by the liver and phosphorylated by fructokinase to form fructose 1-phosphate 400mg viagra plus amex erectile dysfunction forum discussion. This molecule is either isomerized to form glucose 6-phosphate or metabo- lized by the glycolytic pathway purchase 400mg viagra plus otc impotence test. Fructose 1-phosphate is used by the glycolytic pathway more efficiently than glu- cose 6-phosphate. Galactose is an important sugar used not only to provide energy but also in the biosynthesis of glycoproteins and glycolipids. When galactose is taken up by the liver, it is phosphorylated to form galactose 1-phosphate, which then reacts with uridine diphosphate-glucose, or UDP-glucose, to form UDP-galactose and glucose 1-phosphate. The UDP-galactose can be used for glycoprotein and glycolipid biosynthesis or converted to UDP-glucose, which can then be recycled. Gluconeogenesis is the production of very low density lipoprotein; TG, triglycerides; TCA, tricar- glucose from noncarbohydrate sources such as fat, amino boxylic acid. CHAPTER 28 The Physiology of the Liver 519 cible; the lipid droplets coalesce in an aqueous medium. The human liver normally has a consider- lipoprotein particles stabilize the hydrophobic triglyceride able capacity to produce VLDLs, but in acute or chronic center of the particle. During fasting, fatty acids are mobilized from adipose Liver VLDLs are associated with an important class of tissue and are taken up by the liver. The two forms of circulating hepatocytes to provide energy via -oxidation, for the gen- apo B are B48 and B100. The human liver makes only apo eration of ketone bodies, and to synthesize the triglyceride B100, which has a molecular weight of about 500,000. After feeding, chylomi- B100 is important for the hepatic secretion of VLDL. In crons from the small intestine are metabolized peripherally, abetalipoproteinemia, apo B synthesis and, therefore, the and the chylomicron remnants formed are rapidly taken up secretion of VLDLs is blocked. The fatty acids derived from the triglycerides seen in the cytoplasm of the hepatocytes of abetalipopro- of the chylomicron remnants are used for the formation teinemic patients. Although considerable amounts of circulating plasma LDLs and HDLs are produced in the plasma, the liver also Fatty Acid Oxidation and Synthesis. Fatty acids derived produces a small amount of these two cholesterol-rich from the plasma can be metabolized in the mitochondria of lipoproteins. LDLs are denser than VLDLs, and HDLs are hepatocytes by -oxidation to provide energy. The function of LDLs is to transport are broken down to form acetyl-CoA, which can be used in cholesterol ester from the liver to the other organs. HDLs the tricarboxylic acid cycle for ATP production, in the syn- are believed to remove cholesterol from the peripheral tis- thesis of fatty acids, and in the formation of ketone bodies. Because fatty acids are synthesized from acetyl-CoA, any The formation and secretion of lipoproteins by the liver substances that contribute to acetyl-CoA, such as carbohy- is regulated by precursors and hormones, such as estrogen drate and protein sources, enhance fatty acid synthesis. For instance, during fasting, the fatty The liver is one of the main organs involved in fatty acid acids in VLDLs are derived mainly from fatty acids mobi- synthesis. Palmitic acid is synthesized in the hepatocellular lized from adipose tissue. In contrast, during fat feeding, cytosol; the other fatty acids synthesized in the body are fatty acids in VLDLs produced by the liver are largely de- derived by shortening, elongating, or desaturating the rived from chylomicrons. As noted earlier, the fatty acids taken up by the liver can be used for -oxidation and ketone body formation. One of the major functions of the ative amounts of fatty acid channeled for these various pur- liver in lipid metabolism is lipoprotein synthesis. The four poses are largely dependent on the individual’s nutritional major classes of circulating plasma lipoproteins are chy- and hormonal status. More fatty acid is channeled to keto- lomicrons, very low density lipoproteins (VLDLs), low- genesis or -oxidation when the supply of carbohydrate is density lipoproteins (LDLs), and high-density lipoproteins short (during fasting) or under conditions of high circulating (HDLs) (Table 28.
Pronator quadratus Distal fourth of ulna Distal fourth of radius Pronates forearm and hand Median n buy viagra plus 400mg otc best erectile dysfunction pills review. Flexor carpi radialis Medial epicondyle of humerus Base of second and third Flexes and abducts hand at Median n purchase 400mg viagra plus mastercard erectile dysfunction caused by medications. Flexor carpi ulnaris Medial epicondyle and Carpal and metacarpal bones Flexes and adducts wrist Ulnar n. The antebrachial muscles that flex these joints are larger and stronger than those that extend the joints. The hand is a marvelously complex structure, adapted to permit Thus, they also have a greater degree of tonus causing the relaxed hand to be in a grasping position. Flexion and extension move- cal shocks through the arms will tightly flex the joints of their wrist and ments of the hand and phalanges are accomplished by the mus- hands and cling to a cord or wire. Precise finger movements that brachium are stimulated to contract, but the flexors, being larger and require coordinating abduction and adduction with flexion and stronger, cause the hands to close tightly. Muscular System © The McGraw−Hill Anatomy, Sixth Edition Companies, 2001 274 Unit 4 Support and Movement interos- sei Lumbricales (a) Vincula longa (b) FIGURE 9. Muscular System © The McGraw−Hill Anatomy, Sixth Edition Companies, 2001 Chapter 9 Muscular System 275 TABLE 9. Opponens pollicis Trapezium and flexor retinaculum First metacarpal bone Opposes joints of thumb Median n. Intermediate Muscles Adductor pollicis Oblique head, capitate; Proximal phalanx of thumb Adducts joints of thumb Ulnar n. These muscles and associated structures of the hand are Muscles That Move the Thigh depicted in figure 9. The position and actions of the muscles of the hand are listed in table 9. The thenar the pelvic girdle and the vertebral column and insert on various eminence is the fleshy base of the thumb and is formed by three places on the femur. These muscles stabilize a highly movable muscles: the abductor pollicis brevis, the flexor pollicis brevis, hip joint and provide support for the body during bipedal stance and the opponens pollicis. The most massive muscles of the body are found muscles is the opponens pollicis, which opposes the thumb to the in this region, along with some extremely small muscles. It also is formed by three muscles: the abductor digiti minimi muscle, the flexor digiti minimi muscle, Anterior Muscles and the opponens digiti minimi muscle. The anterior muscles that move the thigh at the hip joint are the Muscles of the intermediate group are positioned between iliacus and psoas major (figs. Muscular System © The McGraw−Hill Anatomy, Sixth Edition Companies, 2001 276 Unit 4 Support and Movement FIGURE 9. It is a powerful extensor muscle of the hip joint and is very important for bipedal stance and locomotion. It inserts on the gluteal tuberosity of the femur and the iliotibial tract, a thickened tendinous region of the fascia lata extending down the thigh (see fig. The gluteus medius muscle is located immediately deep to the gluteus maximus (fig. The gluteus medius abducts and medially rotates the hip inserts, along with the iliacus muscle, on the lesser trochanter joint. The psoas major and the iliacus work synergistically for intramuscular injections. These two muscles are collectively called the iliopsoas the gluteal muscles (fig. It originates on the iliac crest and inserts on a broad tensor fasciae latae. Muscular System © The McGraw−Hill Anatomy, Sixth Edition Companies, 2001 Chapter 9 Muscular System 277 FIGURE 9. It is a two-joint muscle and A deep group of six lateral rotator muscles of the hip joint can adduct the hip joint or flex the knee.
An acute ischemic episode may be fol- diac muscle so weakened that it cannot pump strongly lowed by a stunned myocardium cheap viagra plus 400mg with amex gas station erectile dysfunction pills, with reduced me- enough to empty the heart properly with each beat cheap 400 mg viagra plus with amex icd 9 code erectile dysfunction 2011. Chronic ischemia can produce a hi- strictive cardiomyopathy, the muscle becomes so stiff- bernating myocardium, also with reduced mechanical ened and inextensible that the heart cannot fill properly be- performance. Chronic poisoning with heavy metals, such as dling, which can lead to destructively high levels of inter- cobalt or lead, can produce toxic cardiomyopathy. These conditions can be improved by reestab- skeletal muscle degeneration associated with muscular lishing an adequate oxygen supply (e. CHAPTER 10 Cardiac Muscle 187 REVIEW QUESTIONS DIRECTIONS: Each of the numbered (D) The electrical activity is conducted (A) The resting muscle length from which items or incomplete statements in this too slowly for tetanus to occur contraction begins section is followed by answers or 5. The contraction cycle for cardiac (B) The size of the preload, which sets completions of the statement. Select the muscle differs in significant ways from the initial length ONE lettered answer or completion that is that of skeletal muscle. Which of the following sets of attrib- (A) The cycle involves only isometric muscle shortens utes best characterizes cardiac muscle? The factor common to most changes in (A) Large cells, electrically isolated, (B) Isometric relaxation occurs at a cardiac muscle contractility is the neurally stimulated shorter length than isometric (A) Amplitude of the action potential (B) Small cells, electrically coupled, contraction (B) Availability of cellular ATP chemically stimulated (C) The muscle relaxes along the same (C) Cytoplasmic calcium (C) Small cells, electrically coupled, combination of lengths and forces that concentration spontaneously active it took during contraction (D) Rate of neural stimulation (D) Small cells, electrically isolated, (D) The complete cycle in cardiac 10. At a given muscle length, the velocity spontaneously active muscle is isotonic of contraction depends on 2. What is the physiological role of the (A) Only the afterload electrical and a mechanical syncytium. The regulation of contraction in preload SUGGESTED READING cardiac muscle is (D) It prevents a contraction from American Heart Association. Website: (A) Most like that of smooth muscle having an isometric phase at shorter http://www. Why does cardiac muscle shorten less Mechanisms of Contraction of the (i. Boston: Lit- (C) Independent of filament-related (A) Higher loads cause a reduction in tle, Brown, 1976. New York: McGraw-Hill, stimulation (B) Higher loads cause rapid fatigue, 1981. Carmel, IN: Biological Sci- (A) The rate of neural stimulation is premature relaxation ences Press-Cooper Group, 2000. Oxford: Oxford University potential lasts into the relaxation phase important limit to force production in Press, 1979. CASE STUDIES FOR PART III • • • CASE STUDY FOR CHAPTER 8 four limbs, but the woman does not complain of muscu- lar soreness. She is somewhat underweight, slightly Polymyositis in an Older Patient short of breath, and speaks in a low voice. Laboratory A 67-year-old woman consulted her physician because of tests show a moderately elevated creatine kinase level. She reported There is no family history of muscle problems, and she is difficulty in rising out of a chair and had intermittent diffi- not currently taking any medication. Physical examination reveals the Because of the symptoms present, no muscle biopsy presence of a light purple rash around her eyes and on or electromyographic study is carried out. Muscle weakness is noted in all agnosis of polymyositis/dermatomyositis was made. The (continued) 188 PART III MUSCLE PHYSIOLOGY woman is placed on high-dose prednisone, and arrange- steroidal drug to manage the pain and inflammation and ments are made for periodic tests for circulating muscle is told to lessen the pain by applying ice packs to the af- enzymes. He is advised to avoid stair climbing as specialist to screen for a possible underlying malig- much as possible during this time, but to begin walking nancy, and physical therapy is strongly recommended. On a fol- In follow-up visits, the woman shows gradual im- low-up visit 2 weeks later, he is experiencing little im- provement in muscle strength, and her rash is much less pairment in walking, although the strength of the leg is apparent. She maintains a still less than normal and stair climbing is still somewhat regimen of physical therapy and is able to have the pred- of a problem.