By Z. Ines. University of Richmond. 2017.
When cells lose K (and accom- move out of cells and K buy discount provera 2.5mg line, in exchange, to move into cells. This effect appears to be a result of stim- 418 PART VI RENAL PHYSIOLOGY AND BODY FLUIDS Shift K+ to Shift K+ + Ingested K outside of cells into cells 100 mEq/day Body cell Input ECF pH, ECF pH, digitalis, K+ insulin, O2 lack, epinephrine Bone, dense ATP hyperosmolality, connective tissue, hemolysis, cartilage K+ ADP + Pi Extracellular Intracellular infection, 300 mEq fluid K+ + + fluid K ischemia, Na 60 mEq 3,300 mEq trauma Transcellular fluid K+ K+ H+ + HCO - CO + H O 40 mEq 3 2 2 H+ K+ Output + Urinary K K+ in feces excretion 10 mEq/day FIGURE 24. In- sulin (administered with glucose) is also used in the emer- gency treatment of hyperkalemia. In chronic renal failure, hyperkalemia usually does shrink and raises intracellular [K ], which then favors out- not develop until GFR falls below 15 to 20 mL/min because ward diffusion of K into the ECF. The major cause of renal K wasting is iatro- pseudohyperkalemia, results if blood has been mishandled genic, an unwanted side effect of diuretic drug therapy. In un- The plasma [K ] is sometimes taken as an approximate controlled diabetes mellitus, K loss is increased because of guide to total body K stores. For example, if a condition the osmotic diuresis caused by glucosuria and an elevated is known to produce an excessive loss of K (such as taking rate of fluid flow in the cortical collecting ducts. Several a diuretic drug), a decrease in plasma [K ] of 1 mEq/L may rare inherited defects in tubular transport, including Bart- correspond to a loss of 200 to 300 mEq K. Clearly, how- ter, Gitelman, and Liddle syndromes also lead to excessive ever, many factors affect the distribution of K between renal K excretion and hypokalemia (see Table 23. As was discussed in Chapter 23, K is filtered, reabsorbed, and secreted in the kidneys. Most of the filtered K is reabsorbed in the prox- The Kidneys Normally Maintain K Balance imal convoluted tubule (70%) and the loop of Henle Figure 24. K intake (50 to 150 ally the result of secretion by cortical collecting duct prin- mEq/day) and absorption by the small intestine are unreg- cipal cells.
Which of the following sources of muscle weakness and fatigue purchase 2.5 mg provera visa, anorexia, and cholesterol is most important for (B) Catecholamines inhibit weight loss associated with sustaining adrenal steroidogenesis glycogenolysis in the liver gastrointestinal symptoms (nausea, when it occurs at a high rate for a long (C) Catecholamines stimulate the vomiting). A patient receiving long-term (D) Congenital adrenal hyperplasia (E) Cholesterol from the endoplasmic glucocorticoid therapy plans to (E) Hypopituitarism reticulum undergo hip replacement surgery. A 7-year-old boy comes to the (A) Glucocorticoids should be glucocorticoids accelerate pediatric endocrine unit for evaluation decreased to prevent serious gluconeogenesis during fasting? Review of his hypoglycemia during recovery (A) Glucocorticoids stimulate the growth charts indicates substantial (B) Glucocorticoids should be secretion of insulin, which activates weight gain over the previous 3 years increased to stimulate immune function gluconeogenic enzymes in the liver but little increase in height. To and prevent possible infection (B) Glucocorticoids inhibit the use of differentiate between the development (C) Glucocorticoids should be glucose by skeletal muscle of obesity and Cushing’s disease, blood decreased to minimize potential (C) Glucocorticoids maintain the and urine samples are taken. Which of interactions with anesthetics vascular response to norepinephrine the following would be most (D) Glucocorticoids should be (D) Glucocorticoids inhibit diagnostic of Cushing’s disease? Adrenocorticotropin serum cortisol, and decreased serum to result in a decreased rate of (ACTH)- and non-ACTH-mediated insulin aldosterone release? J Clin Endocrinol serum cortisol, and decreased urinary the kidney Metab 1999;84:1729–1736. Congenital adrenal hyperplasia is most concentration at the macula densa DHEA. Baillieres Clin Endocrinol likely a result of (E) An increase in renal sympathetic Metab 1998;12:67–81. Genotyping is a (B) Addison’s disease zona glomerulosa valuable diagnostic complement to (C) Defects in ACTH secretion 7. The rate-limiting step in the synthesis neonatal screening for congenital adre- (D) Defects in corticosteroid-binding of cortisol is catalyzed by nal hyperplasia due to steroid 21-hy- globulin (A) 21-Hydroxylase droxylase deficiency. J Clin Endocrinol (E) Cushing’s disease (B) 3 -Hydroxysteroid dehydrogenase Metab 1999;84:1505–1509. Catecholamines In: Wilson JD, Foster DW, Kronen- How do glucocorticoids influence and the adrenal medulla.
THE ACTIONS OF ANDROGENS the circulation much more slowly if bound to a protein discount 10 mg provera mastercard. Any type of liver damage or disease will generally reduce DHT enhances development of the male reproductive SHBG production. The latter can upset the hormonal bal- tract, accompanying accessory ducts and glands, and male ance between LH and testosterone. A lack of androgen declines acutely, then free testosterone may increase secretion or action causes feminization. In response to the increase in free testosterone, LH levels would decline in a homeostatic attempt to re- Peripheral Tissues Process and duce testosterone production. Metabolize Testosterone Once testosterone is released into the circulation, its Testosterone is not stored in Leydig cells but diffuses into fate is variable. In most target tissues, testosterone func- the blood immediately after being synthesized. An adult tions as a prohormone and is converted to the biologically man produces 6 to 7 mg testosterone per day. This amount active derivatives DHT by 5 -reductase or estradiol by slowly declines after age 50 and reaches about 4 mg/day in aromatase (Fig. Therefore, men do not undergo male reproductive tract contain an active 5 -reductase. DHT has a high binding affinity for the androgen receptor Testosterone circulates bound to plasma proteins, with and is 2 to 3 times more potent than testosterone. About 30 to Congenital deficiency of 5 -reductase in males results 40% is bound to albumin and the remainder to sex hor- in ambiguous genitalia containing female and male char- mone-binding globulin (SHBG), a 94-kDa glycoprotein acteristics because DHT is critical for directing the nor- produced by the liver. SHBG binds both estradiol and mal development of male external genitalia during embry- testosterone, with a higher binding affinity for testos- onic life (see Chapter 39). Because its production is increased by estrogens pathway may predominate, even though the genetic sex is and decreased by androgens, plasma SHBG concentration male and small, undescended testes are present in the in- is higher in women than in men. DHT is nonaromatizable and cannot be voir for testosterone, and therefore, a sudden decline in converted to estrogens. SHBG, in effect, deacti- duce prostatic hypertrophy because DHT induces hyperpla- vates testosterone because only the unbound hormone sia of prostatic epithelial cells.
Get your project done all under one roof…
Core Services
"“Laurence has become an integral part of my business over the last few years creating websites, creatives and more. He always comes up with fresh ideas and is incredibly efficient at getting things done quickly when you have tight deadlines to meet. I would recommend his services to anybody looking for design work.”
Justin Rees
Director, Lead Ad Ventures"
"“Laurence created brand designs, icon and website for our iPad app TagNotate. He was a pleasure to work with, providing a great selection of original artwork and design ideas, and then developing those with us through to the finished product. In all respects he provided a professional, high quality service which I would recommend without reservation.”
Richard Buck
Tagnotate"
"“LJA Studios were very professional in their approach and delivery. They are responsive to feedback and the website evolved exactly as discussed. They were very friendly and walked us through the process, so that at all times we knew exactly what was going on. It exceeded our expectations by far. We have no hesitation in recommending their services, and have actually done so already.”
Delroy Folks
Palace Green Finance Ltd."