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40 Cards in this Set
- Front
- Back
46. Action of PTH?
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a. Inhibits Na+/phosphate cotransport-> Phosphate excretion.
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47. Action of Angiotensin II in Proximal tubule?
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a. Stimulates Na/H+ exchange -> ↑ Na+ and H20 reabsorption (permitting contraction alkalosis).
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48. Action of thick ascending LOH?
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a. Actively reabsorbs Na, K, and Cl.
b. Indirectly induces the paracellular reabsorption of Mg2+ and Ca2+. c. Impermeable to H20! d. Makes urine LESS concentrated. |
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49. Action of Early distal tubule?
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a. Actively reabsorbs Na and Cl-.
b. Diluting segment- Makes urine hypotonic. |
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50. Where does PTH act and what is its action?
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a. Early DCT.
b. ↑ Ca/Na exchange -> Ca2+ reabsorption. |
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51. Action of collecting tubules?
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a. Reabsorb Na in exchange for secreting K and H (regulated by aldosterone).
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52. How does aldosterone cause reabsorption of Na in collecting tubules?
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a. Aldosterone leads to insertion of (reabsorbing) Na channel on luminal side.
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53. Where does ADH act in the kidney and what is its action?
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a. Acts at V2 receptors in collecting tubules.
b. Causes insertion of Aquaporin H2O channels on luminal side. |
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54. TF/P > 1 when? (TF/P = Tubular fluid/plasma)
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a. Solute is reabsorbed less quickly than water
b. There is net secretion of solute. |
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55. TF/P = 1 when? (TF/P = Tubular fluid/plasma)
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a. Solute and water are reabsorbed at same rate
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46. Action of PTH?
|
a. Inhibits Na+/phosphate cotransport-> Phosphate excretion.
|
|
47. Action of Angiotensin II in Proximal tubule?
|
a. Stimulates Na/H+ exchange -> ↑ Na+ and H20 reabsorption (permitting contraction alkalosis).
|
|
48. Action of thick ascending LOH?
|
a. Actively reabsorbs Na, K, and Cl.
b. Indirectly induces the paracellular reabsorption of Mg2+ and Ca2+. c. Impermeable to H20! d. Makes urine LESS concentrated. |
|
49. Action of Early distal tubule?
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a. Actively reabsorbs Na and Cl-.
b. Diluting segment- Makes urine hypotonic. |
|
50. Where does PTH act and what is its action?
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a. Early DCT.
b. ↑ Ca/Na exchange -> Ca2+ reabsorption. |
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51. Action of collecting tubules?
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a. Reabsorb Na in exchange for secreting K and H (regulated by aldosterone).
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52. How does aldosterone cause reabsorption of Na in collecting tubules?
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a. Aldosterone leads to insertion of (reabsorbing) Na channel on luminal side.
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53. Where does ADH act in the kidney and what is its action?
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a. Acts at V2 receptors in collecting tubules.
b. Causes insertion of Aquaporin H2O channels on luminal side. |
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54. TF/P > 1 when? (TF/P = Tubular fluid/plasma)
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a. Solute is reabsorbed less quickly than water
b. There is net secretion of solute. |
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55. TF/P = 1 when? (TF/P = Tubular fluid/plasma)
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a. Solute and water are reabsorbed at same rate
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56. TF/P < 1 when? (TF/P = Tubular fluid/plasma)
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a. Solute is reabsorbed more quickly than water.
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57. Where do Tubular creatinine and inulin ↑ in concentration (but not amount)?
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a. Along the proximal tubule due to water reabsorption.
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58. How does Cl reabsorption compare to Na reabsorption in the proximal tubule and more distally?
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a. Cl reabsorption occurs at a slower rate than Na in the proximal 1/3 of the proximal tubule and then matches the rate of Na reabsorption more distally.
b. Thus, its relative concentration ↑ before its plateaus |
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59. Na vs. H20 reabsorption?
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a. Na reabsorption drives H2O reabsorption, so it nearly matches osm.
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60. Action of AT II in renin-angiotensin-aldosterone system?
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a. Affects baroceptor function.
b. Limits reflex bradycardia, which would normally accompany its pressor effects. |
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61. 6 Actions of Angiotensin II?
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1. Acts at AT II receptors on vascular smooth muscle-> vasoconstriction- ↑ BP.
2. Constricts EFFERENT arteriole -> ↑ FF to preserve renal function (GFR) in low-volume states (i.e., when RBF ↓). 3. Aldosterone 4. Stimulates ADH (posterior pituitary) ↑H2O channel insertion in principal cells -> H20 reabsorption. 5. ↑ proximal tubule Na/H activity -> H20 reabsorption. 6. Stimulates hypothalamus -> Thirst. |
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62. Action of ANP in renin-angiotensin-aldosterone system?
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a. Released from atria in response to ↑ volume.
b. May act as a “check on renin-angiotensin-aldosterone. c. Relaxes vascular smooth muscle via cGMP, causing ↑ GFR, ↓ renin. |
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63. Action of ADH in renin-angiotensin-aldosterone system?
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a. Primarily regulates osmolarity but also responds to low blood volume, which takes precedence over osmolarity.
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64. Action of aldosterone in renin-angiotensin-aldosterone system?
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a. Primarily regulates blood volume.
b. In low-volume states, both ADH and aldosterone act to protect blood volume. c. ↑ Na channel, Na/K pump insertion in principle cells. d. Enhances K+ and H+ excretion (up-regulates principle cell K channels and intercalated cell H+ channels). e. All of this creates favourable Na gradient for Na and h20 reabsorption. |
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65. What are JG cells and where are they?
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a. Modified smooth muscle cells of the AFFERENT ARTERIOLE.
b. JG cells secrete renin in response to ↓ BP, ↓ Na delivery to distal tubule, and ↑ sympathetic tone (β1). |
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66. What are macula densa cells and where are they?
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a. Na+ sensor, part of the DCT.
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67. 4 kidney endocrine functions?
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1. Erythropoietin (you are calling it epo for short)
2. 1,25-(OH)2 vitamin D. 3. Renin 4. Prostaglandin. |
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68. When is epo released and from what cells?
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a. In response to hypoxia from endothelial cells of peritubular capillaries.
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69. Where in the kidney is 25-Vit D converted to 1,25?
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a. Proximal tubule cells convert it.
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70. Action of vit D?
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a. ↑ intestinal reabsorption of both calcium and phosphate.
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71. Action of PTH?
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a. PTH acts directly on kidney to ↑ renal calcium reabsorption and ↓ renal phosphate reabsorption.
b. However, PTH also acts indirectly, stimulates proximal tubule cells to make 1,25-D, which ↑ intestinal absorption of BOTH calcium and phosphate. |
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72. How can NSAIDS cause acute renal failure?
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a. By inhibiting the renal production of prostaglandins, which keep the afferent arterioles vasodilated to maintain GFR.
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73. What is Renin secreted by and what is its effect?
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a. JG cells in response to ↓ renal arterial pressure and ↑ renal sympathetic discharge (β1 effect).
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74. Prostaglandins in kidney (e.g., PGE2)- From where are they secreted and what is their effect?
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a. Paracrine secretion vasodilates the afferent arterioles to ↑ GFR.
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75. Action of Atrial Natriuretic peptide on kidney?
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a. Secreted in response to ↑ atrial pressure.
b. Causes ↑ GFR and ↑ Na filtration WITH NO COMPENSATORY Na REABSORPTION IN DISTAL NEPHRON c. Net effect: Na loss and volume loss. |