C. Amul. Salem College.
He also complained of arise through an increase in protease levels cheap chloroquine 250mg without prescription, a decrease in a cough productive of green sputum chloroquine 250mg without prescription. Chronic obstructive pulmonary disease: An overview smoked two packs of cigarettes a day for the past 30 years purchase 250mg chloroquine visa, of pathology and pathogenesis 250 mg chloroquine fast delivery. Novartis Found Symp he had recently decreased his habit to one pack a day. Although CASE STUDY FOR CHAPTER 20 he has had dyspnea upon exertion for the last 2 years, he continues to maintain an active lifestyle. He still mows his Chest Pain lawn without much difficulty, and can walk 1 to 2 miles on A 27-year-old accountant recently drove cross-country to a flat surface at a moderate pace. He denied having had any other sig- move, she started to experience chest pains. She drove nificant past medical problems, including heart disease, to the emergency department after experiencing 24 hypertension, edema, childhood asthma, or any allergies. She denied any sputum pro- An initial exam shows that the patient is thin but has duction, hemoptysis, coughing, or wheezing. His tive and walks daily and never has experienced any blood pressure is 130/80 mm Hg; respiratory rate, 28 to swelling in her legs. She has never been treated for any 32 breaths/min; heart rate, 92/minute; and oral tempera- respiratory problems and has never undergone any sur- ture, 37. Oral contraceptives are breath sounds in both lung fields, with expiratory wheez- her only medication. A pulse intravenous drugs and has no other risk factors for HIV oximetry reading reveals his blood hemoglobin oxygen disease. Her family history is negative for asthma and saturation is 91% when breathing room air. Pulmonary function tests reveal severe limitation of Physical examination reveals a mildly obese woman airflow rates, particularly expiratory airflow. Her blood Questions pressure is 140/80 mm Hg, and no jugular vein disten- 1. What are the common spirometry findings associated with sion is observed. What are the mechanisms of airflow limitation in emphy- and her temperature is 38 C. What is the most commonly held theory explaining the de- gases, obtained while she was breathing room air, reveal velopment of emphysema? Her alveolar-arterial (A-a)O2 gradient is Answers to Case Study Questions for Chapter 19 40 mm Hg. The hallmark of emphysema is the limitation of airflow out normal flora. In emphysema, expiratory flow rates (FVC, shadow and clear lung fields, except for a small periph- FEV1, and FEV1/FVC ratio) are significantly decreased. A lung scan reveals ever, some lung volumes (TLC, FRC, and RV) are increased, an embolus in the left lower lobe. What is the cause of a widened alveolar-arterial gradient in include hypersensitivity of airway smooth muscle, mucus patients with pulmonary embolism? What causes the decreased arterial PCO2 and elevated arte- creased dynamic airway compression as a result of in- rial pH? Many of the pathophysiological changes in emphysema are Answers to Case Study Questions for Chapter 20 a result of the loss of lung elastic recoil and destruction of 1. This is thought to be a re- embolus will cause blood flow to be shunted to another re- sult of an imbalance between the proteases and antipro- gion of the lung. Because cardiac output is unchanged, the teases ( 1-antitrypsin) in the lower respiratory tree. Nor- shunting of blood causes overperfusion, which causes an mally, proteolytic enzyme activity is inactivated by abnormally low A/ ratio in another region of the lungs. DLCO decreases with anemia because there is less hemoglo- poxemia (a low arterial PO2). In older ever, ventilation is also stimulated as a compensatory individuals, especially those who live alone, insufficient di- mechanism to hypoxemia, which leads to hyperventilation etary intake of animal protein may be the cause; other with a concomitant increase in alveolar PO2.
In addition generic chloroquine 250mg visa, invasion of blood vessels buy 250mg chloroquine mastercard, fibroblastic bright or increased on fluid-sensitive sequences within proliferation safe chloroquine 250 mg, and lymphatic infiltration cheap chloroquine 250 mg without a prescription, the combination the substance of a tendon, a tear is present. Tears can be of which are referred to as angiofibroblastic hyperplasia, further characterized as partial or complete. A complete occur and ultimately lead to mucoid degeneration as the tear is diagnosed by a focal area of discontinuity (Fig. The absence of a significant inflammatory response has been emphasized repeatedly, Epicondylitis and Overuse Syndromes and may explain the inadequacy of the healing process. The imaging findings in this process are exactly those Chronic stress applied to the elbow is the most frequent in- encountered in the clinical entity of medial epicondylitis jury in athletes, and a spectrum of pathology can exist with (Fig. As on the medial side, when pathology is en- varying degrees of severity. The frequency of involvement countered in the tendon, close scrutiny of the underlying of the common flexor and extensor tendons to the medial ligamentous complex is necessary to exclude concomi- and lateral epicondyles, respectively, has led to the desig- tant injury. In particular, thickening and tears of the lat- nation of “epicondylitis” as a general term applied to these eral ulnar collateral ligament have been encountered with overuse syndromes. The injury is believed to result from extrin- sic tensile overload of the tendon, which, over time, pro- duces microscopic tears that do not heal appropriately. Although these overuse entities about the elbow have been termed “epicondylitis” for the purpose of clinical diagnosis, inflammatory osseous changes rarely occur. The imaging findings are those reflecting chronic change in the tendon, as evidenced by tendinosis alone, or in con- junction with partial or complete tear. As previously men- tioned, the distinction between types of pathology is made by consideration of both morphology and signal in- tensity changes. Medial epicondylitis involves pathology of the com- mon flexor tendon and is associated primarily with the sport of golfing. It has also been reported with javelin throwers, racquetball and squash players, swimmers and bowlers. Coronal T1-weighted (left) and fat-suppressed FSE T2- dons are involved most frequently, resulting in pain and weighted images show thickening and intermediate signal intensi- tenderness to palpation over the anterior aspect of the me- ty in the common extensor tendon (arrows), consistent with tendi- dial epicondyle of the humerus and origin of the common nosis (lateral epicondylitis) Magnetic Resonance Imaging of the Elbow 11 Biceps Tendon case of the biceps tendon, an important indirect sign of tendon pathology is the presence of cubital bursitis. Rupture of the tendon of the biceps brachii muscle at the elbow is rare and constitutes less than 5% of all biceps Triceps Tendon tendon injuries. Injuries to the musculotendinous junction Rupture of the triceps tendon is quite rare. The mecha- have been reported, but the most common injury is com- nism of injury has been reported to result from a direct plete avulsion of the tendon from the radial tuberosity. Similar to the pathology encountered in the isting changes in the distal biceps tendon, due to intrinsic distal biceps tendon, most ruptures occur at the insertion tendon degeneration, enthesopathy at the radial tuberosi- site, although musculotendinous junction and muscle bel- ty, or cubital bursal changes. Complete ruptures are injury relates to forceful hyperextension applied to a more common than partial tears. Athletes involved in may include olecranon bursitis, subluxation of the ulnar strength sports, such as competitive weightlifting, foot- nerve, or fracture of the radial head. With more than 2 cm classic presentation of a complete distal biceps rupture is of retraction between the origin and the insertion, a 40% that of a mass in the antecubital fossa due to proximal mi- loss of extension strength can result. Accurate diagnosis is For MRI diagnosis of triceps tendon pathology, it is more difficult in cases of the rare partial tear of the ten- imperative to be aware that the triceps tendon appearance don, or more common complete tear of the tendon with- is largely dependent on arm position. The latter can occur with an intact bicipi- pear lax and redundant when imaged in full extension, tal aponeurosis, which serves to tether the ruptured ten- whereas it is taut in flexion. MRI diagnosis of biceps tendon pathology becomes important in patients who do not present with the classic Entrapment Neuropathy history or mass in the antecubital fossa, or for evaluation of the integrity of the lacertus fibrosus. MRI diagnosis of The ulnar, median and radial nerves may become com- tendon pathology, as previously mentioned, is largely de- pressed at the elbow, leading to symptoms of entrapment pendent on morphology, signal intensity and the identifi- neuropathy. Abnormal nerves may have increased signal cation of areas of tendon discontinuity (Fig. In the intensity on T2-weighted images, focal changes in girth, and deviation that may result from subluxation or dis- placement by an adjacent mass. Nerve compression may be caused by a medial trochlear osteophyte or incongruity between the trochlea and olecranon process. The absence of the triangular reticulum, the anatomic roof of the cubital tunnel, occurs in about 10% of cases, permitting subluxation of the nerve with flexion. It is necessary, therefore, to include axial images of the flexed elbow in patients suspected of this disorder.
H is secreted into the tubule lu- The formation of new HCO3 and the excretion of H are like two sides of the same coin generic chloroquine 250mg with amex. This fact is apparent if men mainly via the Na /H exchanger in the luminal membrane purchase chloroquine 250mg on-line. It combines with filtered HCO3 to form we assume that H2CO3 is the source of H : H2CO3 generic 250mg chloroquine otc. Carbonic anhydrase (CA) in the luminal mem- H (urine) brane (brush border) of the proximal tubule catalyzes the z dehydration of H2CO3 to CO2 and water in the lumen chloroquine 250 mg free shipping. HCO3 (blood) Inside the cell, the hydration of CO2 (catalyzed by in- tracellular CA) yields H CO , which instantaneously forms 2 3 A loss of H in the urine is equivalent to adding new HCO3 to the H and HCO3. The same is true if H is lost from the body via an- the HCO3 ion moves into the blood surrounding the other route, such as by vomiting of acidic gastric juice. In proximal tubule cells, this movement is favored process leads to a rise in plasma [HCO3 ]. Conversely, a loss by the inside negative membrane potential of the cell and by of HCO3 from the body is equivalent to adding H to the blood. To Peritubular Tubular Tubular excrete large amounts of acid, the kidneys must rely on in- blood epithelium urine creased ammonia excretion. Most ammonia is synthesized in HCO - - proximal tubule cells by deamidation and deamination of 3 HCO3 H+ + HCO - the amino acid glutamine: (reclaimed) H 3 (filtered) NH NH CO CO2 + H2O H CO 4 4 2 2 3 CA H CO 2 3 2 Glutamine → Glutamate → -Ketoglutarate (24) CA Glutaminase Glutamate dehydrogenase CO2 H2O As discussed earlier, ammonia is secreted into the urine by two mechanisms. As NH3, it diffuses into the tubular urine; as NH4 , it substitutes for H on the Na /H ex- changer. In the lumen, NH3 combines with secreted H to 2 form NH4 , which is excreted. Fil- For each mEq of H excreted as NH4 , one mEq of new tered HCO3 combines with secreted H and HCO3 is added to the blood. Carbonic anhydrase (CA) is present in tubule cell produces H and HCO3 , as described earlier. In this figure, H2PO4 If excess acid is added to the body, urinary ammonia ex- is the titratable acid formed. The secreted H combines with urine traps more ammonia (as NH ) in the urine. Second, 2– 4 the basic form of the phosphate (HPO4 ) to form the acid renal ammonia synthesis from glutamine increases over sev- phosphate (H2PO4 ). The secreted H replaces one of the Na ions accompanying the basic phosphate. The new HCO3 generated in the cell moves into the blood, to- gether with Na. For each mEq of H excreted in the urine as titratable acid, a mEq of new HCO3 is added to the Peritubular Tubular Tubular blood. This process eliminates H in the urine, replaces blood epithelium urine ECF HCO3 , and restores a normal blood pH. The amount of titratable acid excreted depends on two factors: the pH of the urine and the availability of buffer. If Glutamine Na+ 2 NH + 4 NH + - 4 Cl Peritubular Tubular Tubular α-Ketoglutarate2- NH NH 3 3 blood epithelium urine + NH + Cl- Glucose or H+ 4 CO +H O H+ Na+ 2 2 Na+ + 2 Na HCO - - HPO 2-2Na+ 2H+ 3 HCO3 4 - - + + HCO3 2 HCO3 Na+ (new) H H (filtered) (new) CO2 CO2 + H2O H2CO3 CA - + CO2 2 CO2 +2 H2O 2 H2CO3 H2PO4 Na CA (excreted) FIGURE 25. Ammonium ions are formed A cell model for the formation of titratable from glutamine in the cell and are secreted into the tubular urine FIGURE 25. H from H2CO3 (bottom) is consumed when -ketoglu- 2– tarate is converted into glucose or CO and H O. For each mEq of titratable acid excreted, a mEq of is added to the peritubular capillary blood—1 mEq for each mEq of NH excreted in the urine. Enhanced renal ammonia synthesis and excretion 1) Hydration of CO2 in the cells, forming H2CO3 and is a lifesaving adaptation because it allows the kidneys to yielding H for secretion remove large H excesses and add more new HCO3 to 2) Dehydration of H2CO3 to H2O and CO2 in the the blood. Also, the excreted NH4 can substitute in the proximal tubule lumen, an important step in the reabsorp- urine for Na and K , diminishing the loss of these cations. In the proximal tubule, the two ions Several factors influence the renal excretion of H , includ- are directly linked, both being transported by the Na /H ing intracellular pH, arterial blood PCO , carbonic anhy- exchanger in the luminal plasma membrane.
All of these struc- eventually mature to become the seminiferous tubules purchase 250mg chloroquine with mastercard. In the fe- tures remain attached to the testis and form what is known as the male generic chloroquine 250 mg on line, the primary sex cords will contribute to nurturing tissue of spermatic cord (see fig buy cheap chloroquine 250 mg on-line. Each gonad develops near a mesonephric duct its position in the scrotal sac discount chloroquine 250mg with visa, the gubernaculum is no more than and a paramesonephric duct. During further development, the connecting tubules become the During the physical examination of a neonatal male, a seminiferous tubules, and the mesonephric duct becomes the effer- physician will palpate the scrotum to determine if the testes ent ductules, epididymis, ductus deferens, ejaculatory duct, and semi- are in position. The paramesonephric duct in the male degenerates possible to induce descent by administering certain hormones. If without contributing any functional structures to the reproduc- this procedure does not work, surgery is necessary. In the female embryo, the mesonephric duct degen- is generally performed before the age of 5. Failure to correct the erates, and the paramesonephric duct contributes greatly to situation may result in sterility and possibly the development of a tumorous testis. The distal ends of the paired paramesonephric ducts fuse to form the uterus and the deep portion of the vagina. Male Reproductive © The McGraw−Hill Anatomy, Sixth Edition Development System Companies, 2001 EXHIBIT I Differentiation of the male and female gonads and genital ducts. By 4 months, the gonads have differentiated into male (b) or female (c). Male Reproductive © The McGraw−Hill Anatomy, Sixth Edition Development System Companies, 2001 (a) (a1) (b) (c) (d) (e) (f) EXHIBIT II (a) Differentiation of the external genitalia in the male and female. At 6 weeks, the urethral fold and labioscrotal swelling are differentiated from the genital tubercle. By the twelfth week, the genitalia have become distinctly male (c) or female (d), being derived from homologous structures. Male Reproductive © The McGraw−Hill Anatomy, Sixth Edition Development System Companies, 2001 Abdominal wall Epididymis Testis Pelvic Rectum cavity Gubernaculum Symphysis pubis Developing Labioscrotal penis fold (a) (g) Inguinal canal Testis Gubernaculum (b) EXHIBIT II Continued Ductus deferens Spermatic cord Testis Scrotum Gubernaculum (c) EXHIBIT III The descent of the testes. During development, each testis descends through an inguinal canal in front of the symphysis pubis and enters the scrotum. Male Reproductive © The McGraw−Hill Anatomy, Sixth Edition Development System Companies, 2001 720 Unit 7 Reproduction and Development Ductus deferens (b) (a) (c) (d) FIGURE 20. Of those couples who seek ejaculation) and use this concentrate to artificially inseminate help for infertility, only about 20% are eventually successful in the female. Sterility is similar to infertility, except that it is a perma- nent condition. Sterility may be genetically caused, or it may be the result of degenerative changes in the seminiferous tubules Diseases of the Reproductive System (for example, mumps in a mature male may secondarily infect the testes and cause irreversible tissue damage). In this procedure, a small section of each ductus deferens affect the reproductive systems of both the male and the female near the epididymis is surgically removed, and the cut ends of the (Table 20. A vasectomy prevents transport of their frequency of occurrence in the United States is regarded by spermatozoa but does not directly affect the secretion of andro- health authorities as epidemic. Because sperm cells make up STDs have not been eradicated mainly because humans cannot less than 1% of an ejaculate, even the volume is not noticeably develop immunity to them and because increased sexual activity affected. Further- According to the National Center for Health Statistics, more, many of the causative organisms can mutate so fast that there are currently 5. Males ing 20%, either both partners have some abnormality, or the with this disease suffer inflammation of the urethra, accompanied sterility: L. Male Reproductive © The McGraw−Hill Anatomy, Sixth Edition Development System Companies, 2001 Chapter 20 Male Reproductive System 721 TABLE 20. In fe- males, the condition is usually asymptomatic, and therefore many women may be unsuspecting carriers of the disease. Advanced stages of gonorrhea in females may infect the uterus and the uter- ine tubes. A pregnant woman with gonorrhea who is not treated may transmit the bacteria to the eyes of her newborn during its passage through the birth canal, possibly causing blindness. Syphilis is less common than gonorrhea but is the more serious of the two diseases.