A&PII CH 25: Urinary System HW Q's
nephr- juxta- ur- glomerular(o)- The prefix ____1______ means glomerulus of the kidney. The prefix _____2_____ means kidney. The prefix _____3_____ means situated near. The prefix _____4_____ means urine, urinary tract, or urea.
1. glomerular(o)- 2. nephr- 3. juxta- 4. ur-
Focus Figure 25.1 Medullary Osmotic Gradient May use each more than once or not at all - juxtamedullary - exchangers - multipliers - cortical - cortex - collecting ducts - long nephron loops. - medulla - vasa recta 1. The long nephron loops of the _______ nephrons are located in the renal ________. 2. The _______ create the medullary osmotic gradient and act as countercurrent ________ . 3. The _________ preserve the medullary osmotic gradient and act as countercurrent ________. 4. The ________ use the medullary osmotic gradient to concentrate urine.
1. juxtamedullary; medulla 2. long nephron loops; multipliers 3. vasa recta; exchangers 4. collecting ducts These countercurrent mechanisms establish and maintain an osmotic gradient extending from the cortex through the depths of the medulla. This gradient—the medullary osmotic gradient—allows the kidneys to vary urine concentration dramatically.
nephron glomerulus juxtaglomerular urea 1. The structural and functional unit of the kidney is a _________. 2. Renin is released by cells of the ________ apparatus in response to afferent arteriole pressure and the degree of stretch of the arteriole wall. 3. An elevated level of ________ in the blood is uremia. 4. The specialized capillary bed responsible for the pressure that drives filtration is the ____________.
1. nephron 2. juxtaglomerular 3. urea 4. glomerulus
Through the tubuloglomerular feedback mechanism, how would an increase in filtrate NaCl concentration affect afferent arteriole diameter? Afferent arteriole diameter would stay about the same. Afferent arteriole diameter would increase. Afferent arteriole diameter would decrease.
Afferent arteriole diameter would decrease High NaCl concentration in the filtrate at the JGA indicates that GFR is too high. By decreasing the diameter of the arteriole delivering blood to the glomerulus, HPg is decreased, resulting in lower GFR.
Which of the following processes would be considered as a secretory rather than an excretory activity? Aldosterone release by the adrenal glands Feces elimination by the colon Carbon dioxide removal by the lungs Sweat removal by the skin
Aldosterone release by the adrenal glands
Why do you have to carefully monitor certain patients who are on "loop diuretics" to lower their blood pressure? You do not want them to build up too much water in the renal pyramid. Certain diuretics are not specific and in addition to getting rid of excess water, additional ions like potassium will be secreted. They are at an increased risk for a urinary tract infection. They may excrete too much protein instead.
Certain diuretics are not specific and in addition to getting rid of excess water, additional ions like potassium will be secreted. If the diuretic is not potassium sparing, you must be careful to instruct patients that they may need to adjust their diet or take a potassium supplement while on this medicine.
Focus Figure 25.1 Medullary Osmotic Gradient Sort the items onto the appropriate limb of the nephron loop figures. All items must be sorted.→→ direction of filtrate flow → H2O out of filtrate 300>>>1200 mOsm 1200>>>>100 mOsm NaCl out of filtrate Active transport Water impermeable Passive transport H2O into filtrate NaCl into filtrate
Descending Limb: H2O out of filtrate 300>>>1200 mOsm Ascending Limb: 1200>>>>100 mOsm NaCl out of filtrate Active transport Water impermeable Both: Passive Transport Neither: H2O into filtrate NaCl into filtrate The long nephron loops of juxtamedullary nephrons first concentrate and then dilute the filtrate. In the descending limb, water is reabsorbed as it moves down its osmotic gradient and concentrates the filtrate. In the ascending limb, solutes (Na+Na+ and Cl−Cl−) are actively pumped out and reabsorbed. Since the ascending limb is impermeable to water, this dilutes the filtrate. The solutes left behind in the surrounding interstitial tissue fluid create a vertical osmotic gradient.
The lab results of a newly admitted patient indicate renal impairment. How might this affect the dosing regimen of drugs that are excreted by the kidney? The dosage should be increased. The dosage interval should be shortened. The dosage or the dosage interval may need to be reduced. The drug should not be given.
The dosage or the dosage interval may need to be reduced. If the renal clearance of the drug is reduced by kidney disease, then drugs eliminated by the kidney may need to be given less often, in smaller amounts, or both. This appropriate regimen is often found in information provided by the drug manufacturer.
The myogenic mechanism of renal autoregulation primarily involves smooth muscle in which blood vessels? efferent arterioles systemic arterioles afferent arterioles glomeruli
afferent arteriole By regulating afferent arteriole diameter, the myogenic mechanism affects HPg and therefore GFR. Under normal physiological conditions, this intrinsic control works to maintain GFR despite moderate changes in systemic blood pressure.
Upon reaching what point in the nephron is reabsorption (1) dependent upon the body's needs at the time and (2) regulated by hormones? distal convoluted tubule descending limb of the loop of Henle ascending limb of the loop of Henle proximal convoluted tubule
distal convoluted tubule Distal convoluted tubule (DCT) reabsorption only occurs under the influence of hormonal regulation.
In what part of the renal tubule does parathyroid hormone (PTH) promote the reabsorption of calcium ions? descending limb of the nephron loop collecting duct distal convoluted tubule (DCT) proximal convoluted tubule (PCT)
distal convoluted tubule (DCT) Parathyroid hormone (PTH) promotes the reabsorption of calcium ions in the distal convoluted tubule (DCT).
GFR regulation mechanisms primarily affect which of the following? capsular osmotic pressure (OPc) capsular hydrostatic pressure (HPc) blood osmotic pressure (OPg) glomerular hydrostatic pressure (HPg)
glomerular hydrostatic pressure (HPg) Much like other capillaries in the body, hydrostatic pressure within the glomerular capillaries produces net outward movement of fluid. Unique to glomerular capillaries, HPg is consistently higher than other capillaries (~55 mm Hg), which ensures the one-way movement of fluid and solutes out of the glomerulus under normal conditions.
Your patient's urinalysis shows a large amount of protein in the urine. This suggests a problem in the ____________ collecting duct proximal convoluted tubule peritubular capillaries glomerulus
glomerulus
What does a high concentration of NaCl in the renal tubule at the juxtaglomerular apparatus (JGA) most likely indicate? insufficient NaCl reabsorption due to low GFR insufficient NaCl reabsorption due to high GFR excessive NaCl reabsorption due to low GFR excessive NaCl reabsorption due to high GFR
insufficient NaCl reabsorption due to high GFR After glomerular filtration, NaCl is actively reabsorbed at many locations along the renal tubule. If the filtrate is moving through the tubule quickly, less reabsorption is possible, so more NaCl gets left behind. This means that at the JGA, the NaCl concentration within the filtrate will be high.
Which of the following are mechanisms of intrinsic control of glomerular filtration (renal autoregulation)? myogenic mechanism and tubuloglomerular feedback tubuloglomerular feedback and the renin-angiotensin mechanism sympathetic nervous system control and the renin-angiotensin mechanism myogenic mechanism and sympathetic nervous system control
myogenic mechanism and tubuloglomerular feedback Both of these mechanisms occur strictly within kidney (i.e., intrinsic controls). The myogenic mechanism is mediated by smooth muscle within the afferent arteriole. In contrast, tubuloglomerular feedback is mediated by macula densa cells of the juxtaglomerular apparatus (JGA).
What area of the nephron is responsible for the reabsorption of most of the water from the filtrate as well as most nutrients? descending nephron loop proximal convoluted tubule distal convoluted tubule collecting duct
proximal convoluted tubule Most of the water from the filtrate as well as most nutrients are reabsorbed in the proximal convoluted tubule
Granular cells of the juxtaglomerular apparatus (JGA) regulate GFR indirectly through which mechanism? tubuloglomerular feedback mechanism myogenic mechanism renin-angiotensin mechanism sympathetic nervous system controls
renin-angiotensin mechanism When systemic blood pressure decreases, granular cells release renin which ultimately causes the formation of angiotensin II. Angiotensin II causes widespread vasoconstriction of systemic arterioles and the increase of blood volume due to aldosterone release.
Approximately 80% of the energy used for active transport is devoted to the reabsorption of __________. water potassium glucose sodium
sodium About 80% of the energy used for active transport is devoted to reabsorbing sodium. Na+ is actively transported out of the tubule cells by primary active transport—a Na+-K+ ATPase pump in the basolateral membranes.
Focus Figure 25.1 Medullary Osmotic Gradient Which of the following is NOT a property used to establish the medullary osmotic gradient? the ascending limb's impermeability to water and permeability to salt the blood flow through the ascending and descending portions of the vasa recta the descending limb's permeability to water and impermeability to salt the filtrate flow through the ascending and descending limbs of the long nephron loops of juxtamedullary nephrons
the blood flow through the ascending and descending portions of the vasa recta The flow of blood through the ascending and descending portions of the vasa recta does not establish the osmotic gradient. The vasa recta act as countercurrent exchangers to preserve the osmotic gradient.
Which of the following best describes glomerular filtration rate (GFR)? -the volume of filtrate created by the kidneys per minute -the volume of filtrate created at the glomerulus per liter of blood flowing through the glomerular capillaries -the volume of blood flowing through the glomerular capillaries per minute -the volume of urine leaving the kidneys per minute
the volume of filtrate created by the kidneys per minute Fluid and small solutes that leave the glomerulus are collectively termed filtrate. Glomerular filtration is driven by glomerular hydrostatic pressure (HPg) and produces ~125 ml of filtrate per minute.
Macula densa cells of the juxtaglomerular apparatus (JGA) regulate GFR through which intrinsic mechanism? sympathetic nervous system control tubuloglomerular feedback renin-angiotensin mechanism myogenic mechanism
tubuloglomerular feedback The JGA is a region of the nephron where the afferent arteriole and its associated tubule are closely apposed. This anatomical arrangement allows macula densa cells to adjust GFR according to the NaCl concentration in filtrate. This is called tubuloglomerular feedback because it allows the contents of the tubules (tubulo-) to affect the glomerular filtration rate.
