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25 TheUrinary System
Which of the following is not a function of the kidneys? • Bile production • Excretion of excess ions • Release of erythropoietin • Activation of vitamin D
Urine collection occurs in the _______ of the kidney. • cortex • medulla • columns • pelvis
What fraction of the cardiac output is delivered to the kidneys each minute? • 1/1000 • 1/2 • 1/4 • 3/4
The blood-filtering structure of the kidney is called the __________. • glomerular capsule • renal tubule • glomerulus • nephron
The urine-forming units of the kidney are the __________. • glomerular capsules • renal tubules • glomeruli • nephrons
Based on the histology of a renal tubule, which section would be most severely inhibited if simple squamous epithelium were damaged? • Proximal convoluted tubule • Thin segment of the loop of Henle • Thick segment of the loop of Henle • Distal convoluted tubule
The vasa recta are associated with which structures in the kidney? • Glomeruli • Juxtamedullary nephrons • Afferent arterioles • Cortical nephrons
The juxtaglomerular apparatus is made of ______ cells from the afferent arteriole and the _________ cells of the DCT. • mesangial; filtration • filtration; mesangial • granular; macula densa • macula densa; granular
Which of the following factors contribute(s) to the higher filtration rate in the glomerular capillaries compared with other capillary beds? • The glomerular capillaries are fenestrated. • The diameter of the efferent arteriole is smaller than the diameter of the afferent arteriole. • The visceral layer of the glomerular capsule is very porous. • All of the above contribute.
Which of the following substances would not be found in normal filtrate? • Uric acid • Urea • Proteins • Creatinine
How would eating a high-protein diet affect filtration? • Due to higher colloid osmotic pressure in the glomerular blood, the net filtration pressure would be lower and less filtrate would form. • Too much protein in the diet would abolish all filtration. • High blood pressure from increased plasma proteins would increase filtration to twice its normal rate. • Filtration would be unchanged, but the kidneys would suffer damage.
What type of response by the afferent arterioles would you expect if blood pressure increased? • The afferent arterioles would constrict. • The afferent arterioles would dilate. • The afferent arterioles would stimulate renin release. • The afferent arterioles would not respond to blood pressure changes.
Autoregulatory mechanisms are most effective: • for renin secretion. • when the arterial pressure drops below 80 mm Hg. • at releasing epinephrine. • when the arterial pressure is between 80 and 180 mm Hg.
Extrinsic controls regulate glomerular filtration rate as a means of regulating ________. • systemic blood pressure • cardiac output • urine formation • red blood cell production
Which of the following general functions can be assigned to the renin-angiotensin system? • Water conservation • Blood pressure elevation • Lowering blood sodium levels • Both a and b
Of the filtered solutes, what percentage is reabsorbed by the renal tubule? • 1% • 50% • 99% • 100%
What would be the effect on urine output if sodium channels in the tubule cells were inhibited? • The volume would increase. • The volume would decrease • The volume would decrease by half the sodium concentration. • The volume would decrease by one-tenth the sodium concentration.
Why is glucose in the urine an indicator of diabetes mellitus? • When blood glucose is very high, the filtered glucose occupies all the transport carriers and it is no longer reabsorbed. • Because diabetics cannot regulate their glucose. • When blood glucose is low, it is excreted in the urine. • Because diabetics have high levels of glucagon.
Why do high levels of potassium stimulate aldosterone secretion? • Aldosterone stimulates potassium secretion at potassium-specific pumps. • Aldosterone stimulates the sodium-potassium pump to reabsorb sodium while simultaneously secreting potassium. • Aldosterone stimulates the sodium-potassium pump to secrete sodium while simultaneously reabsorbing potassium. • High levels of potassium accompany high levels of sodium.
Which of the following processes in urine formation is important for regulating blood pH? • Secretion • Reabsorption • Filtration • Countercurrent multiplication
Drinking too much alcohol results in a headache the next day. Why does this happen? • Alcohol stimulates pain receptors in the brain. • Alcohol stimulates sodium reabsorption. • Alcohol stimulates aldosterone secretion. • Alcohol inhibits ADH secretion.
Why is the osmolarity of medullary fluid in the kidney almost four times higher than the osmolarity of plasma? • The loop of Henle acts as a countercurrent multiplier and contributes solutes to the interstitial fluid. • Urea is recycled from the collecting duct and is transported to the interstitial fluid. • The medullary cells in the kidney synthesize solutes to establish the high osmolarity. • Both a and b occur.
How does ADH contribute to the formation of concentrated urine? • ADH increases the permeability of the ascending limb of the loop of Henle to water. • ADH increases the permeability of the descending limb of the loop of Henle to water. • ADH increases the permeability of the collecting duct to water by stimulating the insertion of aquaporins into the luminal membrane. • ADH decreases the permeability of the collecting duct to water by inhibiting the insertion of aquaporins into the luminal membrane.
What role do the vasa recta play in urine formation? • The vasa recta create the medullary osmotic gradient. • The vasa recta protect the medullary osmotic gradient by preventing rapid removal of salt. • The vasa recta receives the dilute filtrate from the distal convoluted tubule. • The vasa recta deliver urea to the medullary interstitial fluid
When considering drug administration, why is it important to know the renal clearance rate of the drug? • It dictates the dosage and frequency of administration of drugs. • It denotes how often drugs are recycled in the kidney. • It is used to determine the healing rate of an infection. • All of the above are factors in renal clearance rate.
Which of the following constitutes the largest solute component of urine? • Sodium • Potassium • Urea • Creatine
A patient feels radiating pain from the side of her body to the anterior abdominal wall. An MRI shows a bulging renal pelvis. Which is the most likely cause? • A kidney stone lodged in the ureter • A bacterial infection • Lack of blood flow to the kidney • An overflow of blood to the kidney
What features of the bladder predispose it to being able to stretch and relax repeatedly? • The wall contains smooth muscle. • The trigone acts as a spring when the bladder empties. • The walls are highly folded into rugae and the epithelium is transitional. • When emptied, the digestive viscera compress the bladder.
The process of voiding the bladder is called ______. • micturition • the urethral reflex • detrusor activation • incontinence
What is the functional difference between a male urethra and a female urethra? • Males have three urethral sphincters. • The male urethra is shared with the reproductive system. • The male urethra is connected to the renal pelvis. • The female urethra is much longer than a male’s.