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26 Cards in this Set
- Front
- Back
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when does the kidney release renin?
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When it senses decreased BP
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What does Renin do?
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Converts Angiotensinogen to Ang I
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What does Ang I do?
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Gets converted to Ang II in the lung capillaries by ACE
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What are the 4 actions of Ang II?
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1. Potent vasoconstriction
2. Increases Aldo release from adrenal cortex 3. Stim ADH release from Post pit 4. Stim hypothal - thirst |
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What are the 2 overall functions of Ang II?
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-Increase intravasc VOLUME
-Increase BP |
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What hormone acts as a check on the RAS? When is it released and from where?
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ANP - atrionaturetic peptide
-In heart failure -From the atria |
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What 2 things does ANP do?
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-Decreases RENIN
-Increases GFR |
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What are Juxtaglomerular cells? What do they do?
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Modified smooth muscle cells in the renal afferent arteriole - secrete RENIN
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What are Macula densa cells? What do they do?
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Modified epithelial cells in the distal tubule - detect LOW sodium and stimulate renin release
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So what are 3 things that stimulate JG cells to release Renin?
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1. Low BP
2. Low urine Na (macula densa) 3. SNS stimulation |
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What are the SNS receptors on the JG cells?
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B1 receptors
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What effect will INCREASED Na in the filtrate have on the renal afferent arteriole?
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VasoCONSTRICT it to decrease the GFR and decrease sodium loss.
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What are the 4 endocrine functions of the kidney?
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1. Renin release
2. EPO release 3. Vit D activation 4. Prostaglandin secretion |
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Where is EPO made and released from the kidney? When?
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-From endothelial cells of the peritubular capillaries
-In hypoxia |
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What activates Vit D in the kidney?
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The enzyme 1a-hydroxylase
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When is 1a-hydroxylase active in the kidney?
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When Parathyroid hormone stimulates it.
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What effect do the Prostaglandins secreted by the kidney have on GFR?
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They increase GFR by vasodilating the aff arteriole
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What can NSAIDS do to kidney function? When?
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Acute Renal Failure - in high vasoconstrictive states
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What are 6 hormones that act ON or for the kidney?
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-Renin
-Ang II -Aldosterone -ADH -ANP -PTH |
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What is the effect of Ang II specifically on the kidney?
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-Increased GFR
-Increased Na reabsorption -Increased HCO3 reabsorption |
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What 2 things stimulate ADH release from the post pit?
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-Decreased blood volume
-Increased plasma OSMOLARITY |
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What does ADH do to the kidney?
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Binds Principal cell receptors and increases Aquaporin expression to increase H2O reabsorption
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What stimulates PTH release from the parathyroid glands?
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Low serum Calcium
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What does PTH do to the kidney? 3 things..
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1. Increases Ca reabspn at DCT
2. Inhibits PO4 reabspn at PCT 3. Activates 1a-hydroxylase to activate Vit D |
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And what is ANF released in response to?
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Increased ATRIAL pressure
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What does ANP do to the kidney?
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-Increases GFR
-Increases Na EXCRETION (to oppose the RAS) |
