Renal Physiology: Filtration, Reabsorption, and Excretion, Exams of Nursing

Download Renal Physiology: Filtration, Reabsorption, and Excretion and more Exams Nursing in PDF only on Docsity! A&P 2 Module 7. 2024 Edition. Real Questions & Answers. Already Graded A+ ________are found in the cortex region of the kidney, except for a portion of their loop of Henle which extends into the medulla. ______pass deeply into the medulla because of their location and their longer loops of Henle. - ANSCortical nephrons; juxtamedullary nephrons ______are sphincters located where the ureters enter the bladder. - ANSUreterovesical valves A vertical cross section shows what three regions inside the kidney? - ANSthe cortex, the medulla, and the pelvis About how many gallons are filtered vs. excreted as urine? - ANSAbout 47 gallons of glomerular filtrate containing the water, nutrients, and essential ions are removed daily from the blood plasma. By the time filtrate enters the collecting ducts, it contains about only 0.5 gallons of urine, with the other 99% being returned to the blood. About what percentage of Na+ is reabsorbed in the PCT? The loop of Henle? The DCT? - ANS65%; 25%; 10% (DCT reclaims nearly all when necessary) ADH is secreted by the ____. - ANSposterior pituitary Angiotensinogen is a pre-enzyme produced by the ___ and freely circulates in the blood. - ANSliver Both ureters open into the bladder via the _____. - ANSureteral orifices Calculate the net filtration pressure for a patient with a blood hydrostatic pressure of 60mmHg, a colloid osmotic pressure of 32mmHg, and a capsular pressure of 18mmHg. - ANSNet filtration pressure = (Outgoing forces - incoming forces) = HP- (COP + Capsular pressure) =60mmHg - (32mmHg +18mmHg)) = 10 mmHg (net outward pressure) Describe normal urine. - ANSNormal excreted urine is usually clear and pale to deep yellow in color depending on the body's degree of hydration. The normal range of urine pH is 4.5 to 8.0. Urine contains about 95% water with about 5% of solutes of varying amounts. Describe the action of ADH. - ANSADH inhibits urine output by increasing the number of channels in the cells of the collecting ducts. Increasing the channels allows water to pass easily from the filtrate and move into the surrounding interstitial space, eventually returning to blood circulation. Water rapidly leaves the filtrate through the channels in the collecting ducts opened by ADH. ADH retains up to 99% of the water in filtrate, and the kidneys excrete a very small volume of highly concentrated urine. Describe the bladder when it is full and when it is empty. - ANSThe bladder is very elastic, collapsing into it a pyramidal shape when empty. As it is filled by urine, the bladder swells and becomes pear-shaped, rising in the abdominal cavity. Describe the distal convoluted tubule. - ANSThe last part of the tubule is the highly coiled distal convoluted tubule which allows for hormonally controlled reabsorption of water and solutes. Mostly the distal convoluted tubule is responsible for the secretion of unwanted substances. Describe the impact of weak acids on a solution. - ANSWeak acids do not significantly contribute to the pH of a solution because in this form, H+ is tightly bound and cannot dissociate to become free H+. Describe the loop of Henle. - ANSThe second section is the hairpin loop of Henle. Initially the loop of Henle has the descending limb followed by the ascending limb. The descending limb allows water loss and the ascending limb allows salt (NaCl) loss. Describe the mechanisms of aldosterone. - ANSAldosterone increases Na+ reabsorption through the excretion of hydrogen ions (H+). Sodium ions are pumped out of the filtrate while hydrogen ions are pumped inside for excretion. Because water follows salt, Na+ reabsorption also causes water reabsorption. A second action of aldosterone is to increase potassium secretion through sodium-potassium pumps. Na+ is pumped out of the filtrate to be returned to the blood while potassium (K+) is excreted in urine. Describe the nervous system control of the renal flow. - ANSWhen the nervous system takes over regulation, the afferent arterioles diameter is narrowed by sympathetic nerve fibers. The release of the hormone epinephrine by the adrenal medulla causes a decrease in renal blood flow and decreases the GFR. Describe the process of micturition. - ANSMicturition is the act of emptying the bladder. As urine accumulates, the rugae flatten and the wall of the bladder thins as it stretches, allowing the bladder to store larger amounts of urine without a significant rise in internal pressure. The urge to urinate usually starts when about 200 ml of urine has accumulated, causing distension of the bladder walls which initiates a visceral reflex arc. This causes the detrusor muscle to contract and the internal sphincter to relax forcing stored urine through the internal sphincter into the upper part of the urethra. A person can consciously resist this initial urge to urinate because the external sphincter is voluntarily controlled. As the bladder continues to fill, the desire to urinate becomes Input from the _______ adjusts the diameter of the renal arteries thereby regulating renal blood flow. - ANSsympathetic nervous system Once circulating angiotensin II reaches the adrenal cortex, it causes the release of the hormone ____. - ANSaldosterone Once water and solutes leave the blood and enter the glomerular capsule it is called ____. - ANSfiltrate The _____ is a continuous outer region with several cortical columns. - ANSRenal cortex The ____glands are located on top of each kidney. - ANSAdrenal glands The bicarbonate buffer system is composed of _____and _____. - ANSweak carbonic acid (H2CO3); bicarbonate ion (HCO3-). The renal medulla is divided into sections called _____. - ANSPyramids The renal tubule is made of: - ANSThree parts: the proximal convoluted tubule (PCT), the loop of Henle, and the distal convoluted tubule (DCT). The urinary system has ____ kidneys, _____ ureters, and _____ bladder. - ANStwo, two, one Trace the flow of blood through the vessels of the kidney from renal artery into the glomerulus and back to the renal vein. - ANS(1) Renal artery, (2) Segmental artery, (3) Lobar artery, (4) Interlobar artery, (5) Arcuate artery, (6) Interlobular artery, (7) Afferent arteriole, (8) Glomerular capillaries, (9) Efferent arteriole, (10) Peritubular or Vasa recta capillaries, (11) Interlobular vein, (12) Arcuate vein, (13) Interlobar vein, (14) Renal vein True or False: A solution has a pH of 0, which is alkaline. - ANSFalse: The closer to 0, the more acidic a solution. True or False: ADH increases water output. - ANSFalse True or false: all reabsorption occurs in the renal tubules by diffusion. - ANSFalse: Some ions require active transport. True or False: The concentration of urea is relatively low in the distal convoluted tubule and the cortex regions of the collecting ducts because the tubules in the cortex are permeable to it. - ANSFalse (concentrations are high in the DCT and cortex regions; these cells are impermeable to urea) True or False: The descending and ascending regions of the loop of Henle have the same reabsorption characteristics. - ANSFalse Urine is carried from the kidneys to the bladder by thin muscular tubes called ____. - ANSureters Water is found in what two main compartments? - ANSIntracellular and extracellular. What are diuretics? - ANSDiuretics are substances that act on the nephron to increase urinary output. What are the normal blood serum levels? (for pH, PCO2, HCO3-) - ANSNormal pH = 7.35-7.45, Normal PCO2 = 35-45 mm, Normal HCO3- = 22-26 mEq/L What are the three major chemical buffer systems in the body? - ANSBicarbonate buffer system for interstitial and plasma fluids; Phosphate buffer system in the urine and intracellular; The protein system is the main buffer of the intracellular fluid. What are the three mechanisms that regulate renal flow? - ANSRenal autoregulation, nervous system control, and hormone control. What are the three regions of the male urethra? - ANSThe prostatic urethra which runs within the prostate gland, the membranous urethra which runs within the urogenital diaphragm and the spongy (penile) urethra. What are the three steps of urine formation? - ANSFor the body to filter the entire blood and then retain the important elements, three processes must take place: filtration, reabsorption and secretion. What are the three types of capillaries associated with nephrons and their function? - ANSThe glomerular capillaries, the peritubular capillaries and the vasa recta. The glomerular capillaries (glomerulus) are highly coiled capillary beds formed from the afferent arteriole, leaving as the efferent arteriole. The peritubular capillaries closely follow the renal tubules and drain into the interlobular vein. the vasa recta which follow the loops of Henle in the juxtamedullary nephrons of the medulla. What causes an increase in the GFR? a decrease? - ANSThe GFR is increased by an increase in the arterial (and therefore glomerular) blood pressure in the kidneys. The GFR and is decreased by an increase in glomerular osmotic pressure most often caused by dehydration. What causes water and solutes to leave the glomerulus? - ANSThe afferent arteriole, which is fed by the interlobular artery, is much larger in diameter than the efferent arteriole. The difference in diameter causes an extremely high blood pressure in the glomerular capillaries, forcing water and solutes out of the blood, thus making filtration possible. Water and solutes leave the glomerulus, enter the glomerular capsule, and subsequently flow into the renal tubule. What happens if the GFR is too slow? too fast? - ANSIf flow is too rapid, needed substances cannot be adequately reabsorbed. If flow is too slow, nearly all the filtrate is reabsorbed, including most of the wastes that should be excreted. What happens in severe acidosis? - ANSIn severe acidosis the blood pH drops below 7.0, and the central nervous system is markedly depressed causing coma and imminent death What happens in severe alkalosis? - ANSIn severe alkalosis the blood pH rises above 7.8, and the nervous system is markedly excited causing extreme nervousness, muscle contraction, convulsion, and death due to cessation of breathing. What happens to cause hyperventilation? hypoventilation? - ANSIf blood pH begins to fall (becomes more acidic), the respiratory center is excited, causing hyperventilation. If blood pH begins to rise (become more alkaline), the respiratory center is depressed, causing hypoventilation. What is a nephron? - ANSThe basic structural and functional unit of a kidney. The function of the nephron is to control the concentration of water and soluble materials by filtering the blood, reabsorbing needed materials and excreting the rest as urine. What is an anion? - ANSAn anion is a negatively charged ion. What is Blood hydrostatic pressure (HP)? - ANSIt is the amount of pressure found inside the blood in the capillaries, driving fluids out of the glomerular capillary. What is capsular pressure? - ANSIt also opposes blood hydrostatic pressure and drives fluid back into the glomerular capillaries. What is Colloid osmotic pressure (COP)? - ANSIt is also called oncotic pressure. COP is dependent on the amount of proteins in the plasma. COP opposes blood hydrostatic pressure by driving fluids back into the capillary beds. What is countercurrent flow? - ANSCountercurrent flow is the movement of fluids in opposite directions through adjacent channels. What is incontinence? - ANSIncontinence is the inability to control micturition voluntarily. What is reabsorption? - ANSThe process of fluid and substances moving from the filtrate back into the blood is called reabsorption.