Term
| T/F. The concentration of Na in plasma changes under physiological conditions. |
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Definition
| False. Under most conditions plasma sodium concentrations remain constant. |
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Term
| What effect will sweating or diarrhea have on oncotic pressure? GFR? |
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Definition
| Sweating or diarrhea will increase oncotic pressure leading to a decrease in GFR. |
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Term
| What effect will a marked increase in sodium intake have on oncotic pressure? GFR? |
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Definition
| There will be a decrease in oncotic pressure b/c water will follow sodium. This decrease in oncotic pressure will increase GFR. |
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Term
| During a hemorrhage there is a loss of fluid and protein. Fluid moves from the interstitial space to the vascular space creating a decrease in oncotic pressure. This should increase GFR, however it does not. Why is this? |
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Definition
| There is also a decrease in arterial blood pressure. This activated the sympathetic nervous system which will cause constriction of afferent arterioles. This response overrides the response to lowered oncotic pressure and GFR decreases. |
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Term
| What are three ways the kidneys receive information about sodium reabsorption? |
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Definition
-Renal sympathetic nerves
-various hormones
-Pressure and composition of the blood perfusing the kidneys |
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Term
| What is the most important controller of sodium reabsorption? |
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Definition
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Term
| Where is aldosterone produced? |
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Definition
| In the zona glomerulosa in the adrenal cortex. |
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Term
| Other than principal cells of the collecting duct, where else does aldosterone stimulate sodium retention? |
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Definition
| Stimulates sodium transport by sweat, salivary glands, and the intestine. Operates as all purpose stimulator of sodium retention. |
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Term
| What inhibits aldosterone secretion? |
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Definition
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Term
| What effect will increasing renal interstitial hydrostatic pressure have on sodium and water reabsorption? |
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Definition
| Will decrease Na and water reabsorption. |
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Term
| What causes ANP secretion? What effect does this have? |
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Definition
An increase in plasma volume cuases ANP secretion. This will:
-Decreases Na+ reabsorption in inner medullary collecting ducts
-acts on granular cells to decrease renin secretion
-acts on adrenal cortex to decrease angiotensin induced aldosterone secretion
-causes afferent arteriole dilation and efferent arteriole constriction which leads to an increase in Na+ secretion
-causes dilation of mesangial cells |
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