PHA 404 Human Physiology Ch 14 Kidneys and Water Regulation Complete
Which of the following statements regarding renal handling of Na+ is correct? A) In the proximal tubule, Na+ is actively transported across the luminal membrane of the tubular epithelial cells. B) Atrial natriuretic factor increases Na+ reabsorption. C) In the absence of aldosterone, Na+ will be secreted by the cortical collecting ducts. D) Na+ is actively reabsorbed in the ascending limb of the loop of Henle. E) Without vasopressin, the collecting duct is impermeable to Na+.
D
Which would result in the greatest stimulation of aldosterone secretion? A) Increasing plasma K+ concentration and decreasing plasma angiotensin II concentration B) Decreasing plasma K+ concentration and increasing plasma angiotensin II concentration C) Increasing plasma Na+ concentration and increasing plasma volume D) Increasing plasma K+ concentration and increasing plasma angiotensin II concentration E) Decreasing plasma Na+ concentration and decreasing plasma angiotensin II concentration
D
T/F The anatomic arrangement of juxtamedullary nephrons in the kidneys is such that the glomerulus, proximal tubule, and distal convoluted tubule are in the renal cortex, while the loop of Henle and collecting ducts lie mainly in the renal medulla.
T
T/F The countercurrent mechanism of the kidney enables the formation of hypertonic urine.
T
T/F The filtered load of water in an average person is approximately 180 L/day.
T
T/F The fluid entering the distal convoluted tubule is hypoosmotic with respect to plasma.
T
T/F The reabsorption of water in the nephron is accomplished due to the generation of an osmotic gradient created by Na+ reabsorption.
T
T/F The spinal reflex for micturition involves stretch receptors in the wall of the bladder that send messages about distension to sympathetic, parasympathetic, and motor neurons in the spinal cord.
T
T/F The total solute concentration in the extracellular fluid is mainly dependent upon the concentration of Na+ in the extracellular fluid.
T
T/F Total-body balance of water and Na+ is largely maintained by regulating urinary loss of these substances.
T
T/F Unlike Na+, K+ is secreted by the nephron tubules.
T
T/F Unlike the renal cortical interstitial fluid, the interstitial fluid of the medulla is hyperosmotic.
T
T/F Voluntary control of micturition involves controlling somatic motor input to the muscles of the external urethral sphincter.
T
T/F Water absorption from the proximal tubule is mainly driven by the active reabsorption of Na+.
T
T/F At the bend of the loop of Henle, the osmolarity of the tubular fluid is more than four times greater than that of the glomerular filtrate when a person is in an antidiuretic state.
T
T/F Both Na+ and Cl- freely filter from the glomerular capillaries into Bowman's space, with no secretion along the renal tubule.
T
T/F Cardiac arrhythmias may be a clinical sign of either K+ depletion or excess.
T
T/F In healthy individuals, the amount of glucose present in urine will be virtually zero because the amount of glucose reabsorption from the filtrate back into the blood prevents excretion.
T
T/F Increasing the GFR tends to increase the excretion rate of sodium.
T
T/F Most of the body's water is located inside cells, whereas most of the body's Na+ is in the interstitial fluid and plasma.
T
Tom is on a health kick and wants to make sure that he is always in balance in terms of total body water. Which of the following is important for him to keep in mind? A) He must ingest more water than is lost in the urine. B) He must ingest more water than is lost by all output pathways combined. C) He must ingest less water than is lost in the urine. D) The water filtered into Bowman's capsule must be 100% reabsorbed. E) The amount ingested plus that metabolically produced must equal the amount of water in the urine.
A
Tracey has been experiencing a fever and a feeling that she needs to urinate every few minutes, even though she has a very low urine volume. She goes to her doctor who tells her that she has a bacterial infection of her bladder. An ultrasound of her ureters indicates that there is no infection in the ureters. Where did the infection begin? A) Her urethra B) Her nephrons C) Her renal arteries D) Her renal pelvis E) None of these sites
A
Water and NaCl reabsorbed from the loop of Henle directly reenter which blood vessels? A) Vasa recta B) Afferent arterioles C) Efferent arterioles D) Cortical peritubular capillaries E) Collecting ducts
A
When blood Ca2+ levels fall below normal, in what ways do the kidneys help restore them toward normal? A) By increasing 1,25-dihydroxyvitamin D3 formation, decreasing tubular phosphate reabsorption, and increasing tubular Ca2+ reabsorption B) By increasing 1,25-dihydroxyvitamin D3 formation, increasing tubular phosphate reabsorption, and increasing tubular Ca2+ reabsorption C) By decreasing 1,25-dihydroxyvitamin D3 formation, increasing tubular phosphate reabsorption, and increasing tubular Ca2+ reabsorption D) Increasing 1,25-dihydroxyvitamin D3 formation and increasing secretion of parathyroid hormone E) By increasing renal secretion of parathyroid hormone and increasing bone resorption
A
Constriction of the ________ decreases hydrostatic pressure in ________. A) afferent arterioles; glomerular capillaries B) efferent arterioles; proximal convoluted tubules C) renal vein; peritubular capillaries D) efferent arterioles; glomerular capillaries E) efferent arterioles; Bowman's capsule
A
Following a few months of noticeably high urine volume, Stephanie's doctor diagnosed her with diabetes insipidus and prescribed her desmopressin, which is a synthetic drug form of vasopressin. A few weeks later, Stephanie accidentally takes two doses instead of one. On that day, what is Stephanie likely to experience? A) An increase in the osmolarity of urine B) An increased urine volume C) A decrease in blood pressure D) A noticeable reduction in thirst and desire to drink water E) None of these would occur
A
How would the kidneys respond to hypoventilation? A) Increasing secretion of H+ and increasing production of new HCO3- B) Increasing secretion of H+ and decreasing reabsorption of HCO3- C) Decreasing secretion of H+ and increasing production of new HCO3- D) Decreasing secretion of H+ and decreasing reabsorption of HCO3- E) Increasing excretion of CO2
A
If a patient with pulmonary disease began to hypoventilate, how would plasma levels of [H+], HCO3-, and PCO2 be changed, compared to normal? A) Increased [H+], increased PCO2, and increased [HCO3-] B) Increased [H+], increased PCO2, and decreased [HCO3-] C) Increased [H+], decreased PCO2, and decreased [HCO3-] D) Decreased [H+], increased PCO2, and decreased [HCO3-] E) Decreased [H+], decreased PCO2, and decreased [HCO3-]
A
In the presence of aldosterone, which nephron region reabsorbs the greatest fraction of the filtered Na+?
A
In what segment of the nephron is the greatest fraction of filtered water reabsorbed? A) The proximal tubule B) The ascending limb of the loop of Henle C) The distal convoluted tubule D) The collecting ducts E) The descending limb of the loop of Henle
A
Most of the reabsorption of filtered calcium is unregulated and occurs in the ________, but an additional amount can be reabsorbed in the ________, depending on the plasma concentration of parathyroid hormone. A) proximal convoluted tubule; distal convoluted tubule B) distal convoluted tubule; proximal convoluted tubule C) proximal convoluted tubule; descending loop of Henle D) distal convoluted tubule; medullary collecting ducts E) distal convoluted tubule; renal corpuscle
A
Which correctly describes renin? A) It is secreted by juxtaglomerular cells in renal afferent arterioles. B) Its secretion is enhanced by high levels of Na+ in the macula densa. C) Its secretion is stimulated by elevated blood pressure in the renal afferent arterioles. D) It acts on the adrenal cortex to stimulate aldosterone secretion. E) It is secreted by the liver in response to low blood pressure.
A
Which of the following is TRUE about how water is handled by the nephron? A) Water is filtered out of glomerular capillaries by bulk flow. B) Water is actively reabsorbed from the proximal tubule, and Na+ follows down its diffusion gradient. C) Water is actively secreted into the descending loop of Henle. D) The permeability of the ascending limb of the loop of Henle is modified by vasopressin. E) Vasopressin inserts pumps in the collecting duct membrane that move water against its concentration gradient.
A
Which of the following statements about renal control of blood acid-base balance is TRUE? A) Increased metabolism of glutamine by renal tubular cells increases the plasma bicarbonate concentration. B) Excretion in the urine of hydrogen bound to phosphate buffers decreases plasma bicarbonate concentration. C) H+ that binds to filtered bicarbonate in the tubular fluid is excreted in the urine. D) When hypoventilation occurs at the lungs, the kidneys compensate by reducing glutamine metabolism. E) The kidneys compensate for a metabolic alkalosis by increasing CO2 production.
A
Which of the following statements concerning the process of glomerular filtration is correct? A) The hydrostatic pressure in Bowman's space opposes filtration. B) The glomerular filtration rate is limited by a transport maximum. C) All of the plasma that enters the glomerular capillaries is filtered. D) The osmotic force due to plasma proteins favors filtration. E) The hydrostatic pressure in glomerular capillaries opposes filtration.
A
Which of the following statements regarding Ca2+ homeostasis is TRUE? A) Parathyroid hormone directly stimulates Ca2+ reabsorption by the kidneys. B) Parathyroid hormone directly stimulates Ca2+ absorption from the GI tract. C) In the absence of parathyroid hormone, plasma Ca2+ levels would be abnormally low, resulting in the hyperpolarization of nerve and muscle membranes. D) When plasma Ca2+ increases above normal, the secretion of parathyroid hormone increases. E) Vitamin D decreases the renal tubular reabsorption of Ca2+.
A
Which stimulates vasopressin secretion? A) Increased plasma osmolarity B) Increased plasma volume C) Ingestion of alcohol D) Decreased aldosterone secretion E) Increased pressure in afferent arterioles
A
Yolanda was born with a rare genetic disease in which the proximal tubules of her nephrons express half the number of aquaporins as is typical. What will be the result? A) Reduced reabsorption of water, although as much reabsorption of Na+ as is typical B) Reduced reabsorption of both water and Na+ in equal proportions C) Reduced reabsorption of all materials in the proximal tubules D) Reduced reabsorption of water, Na+, and glucose in the proximal tubules E) No change to reabsorption at this site
A
You are a scientist for the Federal Drug Administration (FDA). An agricultural company wants to market a new pesticide they have developed for use on produce in the United States. This pesticide is hydrophilic, has a small molecular weight (it is slightly smaller than glucose), and it does not bind to any proteins. Which of the following is an appropriate hypothesis for how this drug will be found in the body? A) The pesticide will mostly be cleared in the feces as it will bind to cholesterol, which is added to the GI tract. B) The pesticide will remain in the blood for a long period as it is not filtered or secreted by the urinary tract. C) The pesticide will mostly be cleared in the urine as it will be filtered but not reabsorbed. D) The pesticide will be cleared through the skin as it will diffuse through the skin layers and evaporate from the surface.
A
Which is TRUE regarding renal tubular reabsorption? A) Reabsorption of Na+ from the proximal tubule occurs as a result of water reabsorption. B) Reabsorption of glucose saturates at a maximum transport rate. C) Urea reabsorption cannot occur at any point along the nephron. D) Toxic substances are removed from the body by reabsorption from peritubular capillaries into the proximal tubule. E) Reabsorption of Na+ only occurs from nephron regions that come after the descending limb of the loop of Henle.
B
Andres has a parathyroid hormone deficiency. He first approached the doctor because he was experiencing ________ and the early blood tests found that he had ________. A) decreased muscular excitability; low plasma calcium levels B) increased muscular excitability; low plasma calcium levels C) decreased muscular excitability; high plasma calcium levels D) increased muscular excitability; high plasma calcium levels E) frequent bones breaks; high plasma calcium levels
B
Following a few months of noticeably high urine volume, Stephanie's doctor diagnosed her with diabetes insipidus. Stephanie's doctor prescribed her desmopressin, which is a synthetic drug form of which of these hormones? A) ACTH B) Vasopressin C) Atrial natriuretic factor D) Angiotensin II E) Insulin
B
Following an intense workout your clothes are drenched in sweat. You estimate you lost at least 0.5 L of sweat. Your (similarly sized) friend skipped her workout to donate blood and you found out she donated 0.5 L of plasma. After these activities, which of you will have a greater increase in vasopressin secretion and why? A) You will have a greater vasopressin secretion because sweat is hyperosmotic to plasma. B) You will have a greater vasopressin secretion because sweat is hypoosmotic to plasma. C) Your friend will have a greater vasopressin secretion because sweat is hypoosmotic to plasma. D) Your friend will have a greater vasopressin secretion because sweat is isosmotic to plasma. E) Your friend will have a greater vasopressin secretion because sweat is hyperosmotic to plasma.
B
In the condition diabetes mellitus, why does glucose appear in the urine? A) The plasma concentration of glucose becomes so high that it diffuses from peritubular capillaries into the proximal tubule, down its concentration gradient. B) The filtered load of glucose becomes greater than the tubular maximum for its reabsorption. C) Without the hormone insulin, glucose cannot enter proximal tubule epithelial cells. D) The rate of tubular secretion of glucose becomes greater than the sum of glucose filtration and reabsorption. E) Without insulin, the glomerular filtration barrier becomes extremely leaky to glucose, which is not normally filterable.
B
Which is TRUE about the hormone vasopressin (also known as antidiuretic hormone, ADH)? A) It is a peptide hormone released from the adrenal gland. B) It triggers insertion of aquaporins into the apical membranes of collecting duct cells. C) It promotes the excretion of more water in the urine. D) It stimulates the excretion of K+ in the urine. E) Its main function is to trigger the secretion of aldosterone.
B
Which of the following does NOT correctly describe kidney function? A) They contribute significantly to long-term regulation of arterial blood pressure by maintaining the proper plasma volume. B) They produce urine of a constant composition at all times, in order to maintain homeostasis of extracellular fluid. C) They excrete metabolic waste products. D) They assist in maintaining proper acid-base balance in the body. E) They secrete hormones.
B
Which of the following is least likely to be filtered into Bowman's capsule in a normal, healthy person? A) Glucose B) Plasma protein C) Sodium D) Urea E) Bicarbonate ion
B
Which of the following most accurately describes the renal transport of Na+? A) Na+ is actively transported in all segments of the tubule. B) Primary active transport of Na+ allows for secondary active transport of glucose and H+ in the proximal tubule. C) Most of the Na+ transport occurs in the distal convoluted tubule and collecting ducts. D) Na+ is actively secreted into the nephron lumen by cells in the cortical collecting ducts. E) Na+ is actively transported across the luminal membrane of proximal tubule cells in exchange for K+, by Na+/K+ ATPase pumps.
B
Which of the following organs is the main site of aldosterone secretion? A) Kidneys B) Adrenal glands C) Systemic and pulmonary blood vessels D) Liver E) The atria of the heart
B
You are a scientist at a drug company where your CEO has asked for your team to create a drug that will inhibit spontaneous emptying of the bladder (incontinence). Which of the following drugs would be effective? A) A drug that enhances the effects of parasympathetic neurons on the detrusor muscle B) A drug that blocks the effects of parasympathetic neurons on the detrusor muscle C) A drug that inhibits the effects of sympathetic neurons on the internal urethral sphincter D) A drug that inhibits the effects of somatic neurons on the bladder E) A drug that inhibits the action of sympathetic neurons on the external urethral sphincter
B
You are an EMT and arrive at the scene of an opioid overdose. The overdose victim is breathing extremely slowly and shallowly. When you arrive at the ER, you report that the medical team should watch out for signs of A) metabolic acidosis. B) respiratory acidosis. C) metabolic alkalosis. D) respiratory alkalosis.
B
After prolonged exertion in a hot climate, baroreceptors would ________ firing, leading to ________ secretion of ________ and thus ________ renal reabsorption of ________. A) increase; increased; renin; increased; Na+ B) decrease; increased; renin; decreased; Na+ C) decrease; increased; vasopressin; increased; water D) increase; decreased; vasopressin; decreased; water E) decrease; decreased; vasopressin; increased; water
C
Compared to the normal plasma osmolarity, the tubular fluid is ________ as it enters Bowman's space, ________ at the beginning of the loop of Henle, ________ at the tip of the loop, and ________ at the beginning of the distal convoluted tubule. A) isosmotic; hyperosmotic; hyperosmotic; isosmotic B) isosmotic; isosmotic; hypoosmotic; hypoosmotic C) isosmotic; isosmotic; hyperosmotic; hypoosmotic D) isosmotic; isosmotic; hypoosmotic; hyperosmotic E) isosmotic; isosmotic; hyperosmotic; isosmotic
C
How does the renal countercurrent multiplier mechanism allow the creation of a concentrated urine? A) It transports NaCl from the medullary interstitial fluid into the collecting duct, which directly increases the osmolarity of the urine. B) It transports urea from the medullary interstitial fluid into the collecting duct, which directly increases the osmolarity of the urine. C) By concentrating NaCl in the renal medullary interstitial fluid, it allows water to be reabsorbed from the collecting ducts when vasopressin is present. D) By pumping NaCl and urea into the ascending limb of the loop of Henle, it raises the solute load, which turns into a concentrated urine once water is extracted from the collecting duct. E) When anti-diuretic hormone is present, it stimulates the pumping of NaCl from the medullary interstitial fluid and water follows, concentrating the urine.
C
Jerome has had too many alcoholic drinks at a party. One of the effects of alcohol is that it inhibits the release of vasopressin. Which of the following is Jerome likely to notice? A) A reduction in urine volume B) The excretion of glucose in the urine increased C) High volume of dilute urine D) Very concentrated urine E) An increase in blood pressure
C
What is the rate-limiting (regulated) step for stimulating the secretion of aldosterone? A) Conversion of angiotensin I to angiotensin II in the blood B) Secretion of angiotensinogen by the liver C) Conversion of angiotensinogen to angiotensin I in the blood D) Secretion of ACTH by the anterior pituitary E) Secretion of angiotensin II by the kidney
C
What region of the nephron reabsorbs about two-thirds of filtered Na+ and Cl-? A) Ascending loop of Henle B) Glomerulus C) Proximal convoluted tubule D) Distal convoluted tubule E) Collecting duct
C
Which of the following describes tubular reabsorption in the kidney? A) The movement of substances from the peritubular capillaries into the tubular fluid B) The movement of substances from the proximal tubule into the loop of Henle C) Transepithelial transport from the lumen of the tubule into renal interstitial fluid D) Movement of Na+, Cl-, and water from glomerular capillaries into Bowman's capsule E) Transport of solutes from the renal medullary interstitial fluid into the collecting duct
C
Which of the following substances undergoes renal tubular secretion? A) Ca2+ B) Na+ C) K+ D) H2O
C
Which of the following would occur if a person lost the ability to synthesize vasopressin? A) The ability to reabsorb water in the proximal tubule would be lost. B) The excretion of glucose in the urine would increase. C) The urine would become hypoosmotic compared to plasma. D) The urine production would decrease dramatically, and the urine osmolarity would be hypertonic compared to plasma. E) Blood pressure would increase significantly.
C
You have a patient with extensive birth defects that affect the kidney anatomy. Nevertheless, she does have some kidney function. One thing you've noticed in her labs is extremely low renin secretion. Which of the following anatomical locations is likely to exhibit abnormal development? A) The ascending limb of the loop of Henle B) The glomerular capillaries C) The juxtaglomerular apparatus D) The proximal tubule E) The efferent arteriole
C
A man with hypertension takes a diuretic that is not potassium-sparing, and he does not increase his ingestion of potassium. Which of the following side-effects would the drug be most likely to cause? A) Increased blood volume B) Depolarized neuronal cell membranes C) Hyperkalemia D) Cardiac arrhythmia E) All of these side effects would occur.
D
Following a series of high-intensity training runs, lactic acid was generated by the leg muscles and is now circulating in the blood. Which of the following is likely to occur? A) Decreased renal secretion of hydrogen ion B) Decreased renal reabsorption of bicarbonate ion C) Increased plasma PCO2 D) Decreased urinary pH E) Decreased urinary ammonium
D
The amount of a substance that is excreted in the urine is equal to the amount that is ________ plus the amount that is ________ minus the amount that is ________. A) filtered; reabsorbed; secreted B) reabsorbed; filtered; secreted C) secreted; reabsorbed; filtered D) filtered; secreted; reabsorbed E) reabsorbed; secreted; filtered
D
Which is NOT a transport mechanism typically seen in renal tubular epithelial cells? A) Cotransport proteins in the luminal membrane of the proximal tubule that move Na+ and glucose from the proximal tubule into epithelial cells B) Transport proteins that move glucose by facilitated diffusion from inside of proximal tubule cells into the renal interstitial fluid C) Ion channels that allow Na+ to move by diffusion from the lumen of the proximal tubule into epithelial cells D) Na+-K+ ATPase pumps in the luminal membrane of proximal tubule epithelial cells that move Na+ from inside the cell into the tubule and K+ from the tubule lumen into the cell E) Countertransport proteins that move Na+ into proximal tubule epithelial cells while moving H+ from the cells into the lumen
D
You are the CEO of a drug company where you've asked five teams of scientists to generate new drugs to decrease blood pressure. You can only send four of the drugs to market. Which of these drugs is least likely to decrease blood pressure and can be eliminated from potential development? A) A drug that interferes with aldosterone synthesis B) A drug that is an agonist of atrial natriuretic factor C) A drug that decreases sympathetic stimulation of renal arterioles D) A drug that enhances the activity of angiotensin-converting enzyme E) A drug that decreases liver production of angiotensinogen
D
You play a trick on your little brother and replace all the sugar in the sugar bowl with salt. In the morning, you find him eating a bowl full of cereal with salt on it. You realize he's eaten quite a bit of salt! Which is likely to occur?
D
Which correctly describes the composition of the glomerular filtrate? A) It is identical to urine, but has a much smaller flow rate. B) It is identical to urine, but has a much larger flow rate. C) It is identical to blood plasma, except it lacks red blood cells. D) It is similar to plasma, except it does not contain glucose. E) It is similar to plasma, except it does not contain plasma proteins.
E
Which correctly describes a basic renal process? A) Fluid is filtered from Bowman's capsule into the glomerulus. B) Substances are secreted from the tubule into the peritubular capillaries. C) Substances are reabsorbed from the peritubular capillaries into the tubular lumen. D) Substances are actively secreted from glomerular capillaries into Bowman's capsule. E) Fluid moves by bulk flow from glomerular capillaries into Bowman's space.
E
T/F An increase in the osmolarity of the blood supplying the hypothalamus is a powerful stimulus for thirst.
T
After a day of fasting during Ramadan, Amira's blood Na+ level is quite low. Which of the following is likely to occur? A) An increase in plasma volume, which induces an increase in GFR and Na+ reabsorption rate B) A decrease in plasma volume, which induces an increase in GFR and Na+ reabsorption rate C) An increase in plasma volume, which induces an increase in GFR and a decrease in Na+ reabsorption rate D) A decrease in plasma volume, which induces a decrease in GFR and Na+ reabsorption rate E) A decrease in plasma volume, which induces a decrease in GFR and an increase in Na+ reabsorption rate
E
All of the following substances are present in proximal tubular fluid in the kidney, but which one is NOT normally present in urine? A) Ca2+ B) H+ C) K+ D) HPO42- E) Glucose
E
Carl has hypothyroidism and therefore his Na+/K+ ATPase pumps are functioning at a reduced rate. Will there be any effect on the transport of Na+? A) There will be a reduction in Na+ transport in Bowman's capsule epithelial cells. B) There will be a reduction in ATP-dependent, Na+ transport on the apical side of the tubule epithelial cells. C) There will be a reduction in Na+ secretion on both sides of the tubule epithelial cells. D) There will be no change to Na+ transport. E) There will be a reduction in Na+ transport on the basolateral side of the tubule epithelial cells.
E
In which region of the nephron does the fractional reabsorption of water vary the most in response to variation in the state of hydration? A) The glomerulus B) The proximal convoluted tubule C) The loop of Henle D) The distal convoluted tubule E) The collecting duct
E
Which equation is equal to the net glomerular filtration pressure? A) GFP = hydrostatic pressure in glomerular capillaries - hydrostatic pressure in Bowman's capsule - osmotic pressure due to protein in Bowman's capsule B) GFP = osmotic pressure due to protein in plasma - hydrostatic pressure in glomerular capillaries - hydrostatic pressure in Bowman's capsule C) GFP = hydrostatic pressure in glomerular capillaries + hydrostatic pressure in Bowman's capsule + osmotic pressure due to protein in plasma D) GFP = hydrostatic pressure in glomerular capillaries + hydrostatic pressure in Bowman's capsule - osmotic pressure due to protein in plasma E) GFP = hydrostatic pressure in glomerular capillaries - hydrostatic pressure in Bowman's capsule - osmotic force due to proteins in plasma
E
Which is NOT true about the countercurrent multiplier system of the kidney? A) It creates a hyperosmolar medullary interstitial fluid that allows the kidneys to form hypertonic urine. B) The descending loop of Henle is permeable to water. C) There is active transport of sodium and chloride out of the ascending limb of the loop of Henle. D) The ascending loop of Henle is not permeable to water. E) The fraction of filtered NaCl reabsorbed from the ascending limb equals the fraction of filtered water reabsorbed from the descending limb.
E
Which of the following most accurately describes the actions of aldosterone? A) Aldosterone increases Na+ secretion and K+ reabsorption in the cortical collecting ducts. B) Aldosterone increases Na+ reabsorption and K+ secretion in the proximal tubule. C) Aldosterone decreases Na+ reabsorption and K+ secretion in the cortical collecting ducts. D) Aldosterone increases Na+ secretion and K+ reabsorption in the proximal tubule. E) Aldosterone increases Na+ reabsorption and K+ secretion in the cortical collecting ducts.
E
Which of the following would cause a decrease in the excretion of Na+ and water? A) Increased hydrostatic pressure in the afferent renal arterioles B) Increased mean arterial blood pressure C) Increased atrial distension D) Decreased aldosterone secretion E) Decreased atrial natriuretic peptide secretion
E
Which one of the following substances is LEAST dependent on the kidney for regulation of its plasma concentration? A) Water B) Na+ C) K+ D) HPO42- E) Glucose
E
Which would NOT be caused by a decrease in plasma Ca2+ levels in an otherwise normal person? A) An increase in plasma parathyroid hormone levels B) An increase in plasma 1,25-dihydroxyvitamin D3 levels C) An increase in nerve and muscle excitability D) A decrease in the filtered load of Ca2+ E) An increase in bone density
E
T/F A consequence of lack of vasopressin is excretion of sugar in the urine, which occurs in the condition diabetes mellitus.
F
T/F A person lacking vasopressin would have to drink 180 L of water per day to make up for the water lost in the urine.
F
T/F A person on a high-protein diet will have high levels of protein in their urine.
F
T/F Atrial distension is a stimulus for the secretion of atrial natriuretic factor, which stimulates the reabsorption of sodium by the kidneys.
F
T/F Because fluid loss as sweat is isoosmotic, the baroreceptor reflexes are more important than osmoreceptor activity in restoring extracellular fluid volume after sweating.
F
T/F Following hemorrhage, vasopressin secretion increases because of increased firing of hypothalamic osmoreceptors.
F
T/F If water intake (ingestion) is decreased, the kidney can decrease the amount of water excreted in urine by increasing the amount of water reabsorbed at the renal corpuscle.
F
T/F In the absence of vasopressin, urine is isoosmotic with plasma.
F
T/F In the proximal convoluted tubule the reabsorption of Na+ is unaffected by the presence or absence of other substances such as glucose or H+ in the filtrate.
F
T/F Ingestion of large amounts of K+ triggers reflexes to limit the amount of K+ reabsorbed by the cortical collecting ducts.
F
T/F Only substances that are filtered by the kidneys can be excreted by them.
F
T/F Regulation of extracellular K+ is not critical to body function because only about 2% of the total-body K+ is in the extracellular fluid.
F
T/F Stimuli that cause increased Na+ reabsorption decrease K+ secretion.
F
T/F The kidneys regulate the plasma concentrations of water, sodium, and glucose.
F
T/F The main force responsible for water reabsorption from the collecting ducts is the low hydrostatic pressure in the surrounding interstitial space.
F
T/F The three basic processes of kidney function are filtration from the glomerulus into Bowman's capsule, secretion from the tubule into the peritubular capillaries, and reabsorption from the capillaries into the tubular lumen.
F
T/F The walls of the ascending limb of the loop of Henle are freely permeable to water.
F
T/F Water, sodium, and glucose all undergo tubular reabsorption, but urea does not.
F
T/F A misguided athlete ingests a large amount of dietary K+ because she thinks it will boost muscle performance. Instead, the majority of this extra K+ is secreted into filtrate and excreted in the urine.
T
T/F A patient receives an IV (intravenous) infusion of a concentrated, 9% saline solution (0.9% is considered isosmotic). Even if there was no change to the volume of blood or water in the body, this patient is likely to experience extreme thirst following the infusion.
T
