Term
| What is the equation for Filtration fraction? |
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Definition
FF = GRF/RPF
normal is about 20%
RPF = (1-hematocrit) x RBF |
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Term
| Equation for renal blood flow? |
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Definition
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Term
| What is the equation for GFR? |
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Definition
| GFR - Kf x Net filtration pressure |
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Term
| What is the equation for creatinine clearance? |
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Definition
| CrCl = urine cr x volume/plasma Cr X time |
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Term
| What is the equation if you want to use plasma Cr as a way to see GFR? |
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Definition
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Term
| What are the stimulators of the RAS system? |
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Definition
- Hypokalemia
- Hypovolemia
- Prostaglandins
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Term
| What are the inhibitors of the RAS system? |
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Definition
- Negative feedback from angiotensin II
- hyperkalemia
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Term
| What stimulates aldosterone |
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Definition
- hyperkalemia
- angiotensin II
- ACTH (but not that much)
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Term
| What does aldosterone do? |
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Definition
- stimulates Na/K ATPase transporters in collecting tubule and in the peripheral cells resulting in cellular uptake of K and increase in serum Na.
- increases permeability of luminal membrane
- increases H secretion in the tubule as well
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Term
| What do prostaglandins do and where do they come from? |
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Definition
- Produced in the renal medulla and mesangium
- dilate the (previously constricted by the SNS) afferent arterioles
- they may antagonize ADH (this sortof makes sense in that if you have too much volume it will discourage ADH activity)
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Term
| What 3 things stimulate ADH? |
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Definition
- hypovolemia - baroreceptors (central we figure), more potent
- hyperosmolarity - osmoreceptors, more sensitive
- nausea (NOT THIRST)
- *AII stimulates thirst
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Term
| What is atrial naturetic peptide? |
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Definition
- peptide released from the atria when they get stretched
- increases urine flow and Na excretion to bring the volume down
- also causes vasdilation
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Term
| What is the equation for filtration of a substance? |
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Definition
Filtration = GFR x plasma []
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Term
| What is the threshold and transport maximum for glucose? |
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Definition
- Threshold is 12-14 mmol/L
- You know you've reached the transport max when the increase in plasma glc is parallel to the change in urine glc. The difference between threshold and maximum is called the "splay"
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Term
| Talk about urea reabsorption |
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Definition
- urea is highly diffusable at about half to 2/3 the rate of water diffusion
- every 3 water that moves that will take like 2 urea molecules through
- with ADH, urea is permeable in the medullary segment
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Term
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Definition
- urea is let into the medullary interstitium by ADH
- urea is secreted into the tubule in the thin ascending limb
- urea is used as a solute to make urine concentrated
- you would recycle it so that you don't waste protein
- (look at KD 13 and 14)
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Term
| What increases uric acid levels? |
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Definition
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