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PHYS3
Kidneys: Regulation of Sodium and Water
| Question | Answer |
|---|---|
| What is insensible loss? | Loss of water due to respiratory tract |
| How does the body gain sodium and chloride? | Ingestion |
| How about loses them? | skin, GI tract and urine |
| How much sodium and chlrodie do we gain from food? | 10.5 |
| How much do we output from sweat, feces, and urine? | 0.25; 0.25; 10.5 |
| How do we control sodium and water balance? | Renal excretion |
| Where is sodium filtered? | glomerulus |
| What is active sodium reabsorption dependant on? | Sodium potasium pump, |
| where are the pumps? | basolateral membranes of the tubular epithilium |
| Give an example of when sodium enterance into cell is PASSIVE: | sodium from tubular lumen |
| What are the three ways it can do this? | Channels, co transport, counter transport |
| What is the channel method to get it to tubular system? | Put potasium in to get sodium out |
| Tell me how we get sodium to enter the cell by channels starting from Interstitial fluid: | Potasium enters from IF (Active)-->goes through channel to get into lumen and this allows sodium to diffuse in |
| What is important in the channel explination? | K flux, Sodium, potasium ATP pump |
| SODIUM REAPSORPTION | NA REABSORBED |
| What is the reabsorption process, active or passive? | Active process |
| How does it work? | You create an osmotic different acrross tubule, which drives water reabsorption (passive) |
| POINTS REGARDING WATER | REABSORPTION |
| Where is water freely filterable? | glomerulus |
| How is it reabsorped? | Passive diffusion |
| Where is permeability to water high? | Proximal tubule |
| ROLE OF ADH | ROLE OF ADH |
| Where does ADH start working? | Collecting ducts |
| What does ADH do to water permeabilit? | Increases it |
| what happens when ADH is low? | Lots of dilute urine forms |
| URINE CONCENTRATION | URINE CONCENTRATION |
| When ADH is high, what happens? | Small amount of concentrated urine is produced by renal counter-current multiplier |
| What do counter currents do? | they work together to retain water |
| Is the ascending loop of henle working with ADH? | No |
| What is the ascending loop of henle responsible for? | pulls sodium out |
| What is teh ascending loop's permeability to h2O? | Not much |
| What does the descending limb do? | Pull out water by diffusion |
| What does ADH do to the collecting ducts? | Increases their water permeability |
| RENAL SODIUM REGULATION | RENAL SODIUM REGULATION |
| What is the equation for sodium excretion? | Sodium filtered - sodium reabsorbed |
| Does sodium get secreted? | NO NO NO |
| What method is used for its reabsorption? | Active |
| What controls glomeluar filtration rate? | baroreceptor |
| What does a decrease in pressure make trh baroreceptors do? | Decreases their firing, so it increases sympathetic response |
| What does sympathetic response lead to regarding vessel diameter and flow? | vasoconstriction; reduction in flow |
| What does vasoconstriction lead to? | Decreased GFR and increased sodium reabsorption |
| CONTROL OF SODIUM RESORPTION | SODIUM RESOPRTION CONTROL |
| What hormone controls this? | Aldostrone |
| Increase in aldostorne leads to what? Where? | Increase sodium resoprtion in coritcal collecting ducts |
| What controls aldostrone secretion? | Renin-Angiotensin system |
| Renin: | rate limiting variable |
| Where is renin secreted from? | Juixtaglomerular ells |
| What does renin do? | Makes angiotensin I from angiotensinogen |
| What si a stimulus for aldostorne release? | Low sodium volume or water volume |
| What is angiotensin I cleaved by? | ACE (converting enzyme) |
| What does ACE do? | Makes angiotensin II |
| If there is an ACE inhibitor, what happens? | No cleaving of I to II |
| What does Ang II do? | Makes cortex secrete aldostorne |
| What are teh three stimuli for renin secretion? | 1. Baroreceptor____2. Pressure decrease___3. Low sodium or chlride in macula densa |
| What does #2, PB decrease lead to? | Juxtaglomerular cells sense it as intrarenal baroreceptors |
| Where si the macula densa? | Near juxtameddullary cell |
| DON'T ABSORB SODIUM MECHANISMS | DON'T ABSORB SODIUM |
| What is ANF? | Secreted by atria, inhibits sodium reabsorption and increase GFR |
| What does it inhibit, specifically? | Renin and aldostrone secretion |
| RENAL WATER REGULATION | RENAL WATER REGULATION |
| What happens to fluid formation if GFR is low? | Not much fluid made |
| How is water absorption mainly controlled? | ADH and baroreceptors |
| What triggers ADH release? | Decrease IN ECF volume |
| What is ADH controlled by? | Cardiovascular baroreceptors and osmoreceptors |
| What do the osmoreceptors do? | If too dilute, then secrete urine |
| High osmolarity makes us secrete or hold off on ADH? | Increase ADH |
| THIRST AND APETITE | THIRST AND APETITE |
| Do humans have salt apetite? | nope |
| THIRST | THIRST |
| What stimulates thirst? | baroreceptors, osmoreceptors, and angiotensin II |
| Water intake by GI tract, increases or decreases thrist? | Decreases |
| POTASIUM REGULATION | POTASIUM REGULATION |
| Where is potasium freely filterable? | glomerulus |
| Where does secretion of potasium occur? Does absorption and secretion of potasium occur? | Cortical collecting duct; both secrtion and excretion |
| What happens when body K+ levels are high? | Aldostrone secreted, which stimulates EXCRETION of Potasium |
Created by:
talkglitter2486