Regulation ECF and OSM Flashcards
Amount of intake from beverages? Food? Metabolism?
Beverages= 60%
Food= 30%
Metabolism= 10%
Amount of output from feces, sweat, insensible loss, urine?
Feces= 4%
Sweat= 8%
Insensible= 28%
Urine= 60%
What changes happen in intake/output balance with warm weather, exercise
Increase in sweat, loss via respiratory system, decrease urine
What happens when you take in excess h2o?
ECF OSM decreases–> decrease ADH secretion–> decrease plasma ADH–> DECREASE tubular permeability to H2O–> Decrease H2O reabsorbe–> increase H2O excreted
How does urine flow respond to 1200 mL H2O?
Plasma osmolarity decreases, urine flow rate increases promptly, and plasma osmolarity is corrected fairly quickly
What happens to concentration gradient in loop of henle when flow through vasa recta is fast?
Gradient gets washed away!
This is why drinking 1 gallon of water in 20 minute can cause osmotic gradient to be washed away, causing you to urinate for 24 hours + until concentration gradient can be restablished
What happens to urine flow rate when given 1200mL bolus of saline?
No significant change in plasma osmolarity, so there si little change in urine flow rate. Small bump about 2 hours later
An ____ in GFR will increase filtered load of sodium
increase
What do we regulate to control sodium levels?
Filtration and reabsorption
What do you change to change filtration of Na?
GFR
What % Na absorbed in proximal tubule?
67%
What % Na reabsorbed in TAL?
25%
What % Na absorbed in DT/CD?
4%- DT
3% CD
What happens to GFR with salt and water loss? How does this happen
GFR decreases
Where are barorecptors located in kidney? What do they release?
Located in afferent arteriolar vessel walls
Release renin.
What are effects of activation of RAAS system?
- Angiotensin II goes to stimulate:
- sympathetic activity
- tubular Na, Cl reabsorption and K excretion.
- h2o retention
- aldosterone secretion
- arteriolar vasoconstriction
- increase ADH
- increases H2O reabsorption
- Overall effect
- water and salt retention
- effective circulating volume increases
- perfusion of juxtaglomerular apparatus increases
What influences the neurohumoral control of renal sodium reabsorption?
- Sympathetic nerves
- RAAS
- Aldosterone
- ANP
What does increaes sympathetics cause in kidney?
- Increase renin secretion
- increases aldosterone
- Increase afferent and efferent arteriole constriction
- this decreases GFR
- Increase Na reabsorption in proximla tubule
- directly does this, unsure how
What does aldosterone do to distal tubule?
- open up Na channel on apical membrane
- increase number Na-K ATPase pumps on basolateral membrane
- Increase K secretion
What effect does angiotensin II have on proximal tubule?
Increase aldosterone
vasoconstrict afferent and efferent arterioles, decreasing GFR
Increase amount of Na/H antiporter on lumen of proximal tubule
What does ANP (or ANF) do in kidney?
- Decreases renin, decreases aldosterone
- promote salt and h2o excretion by decreasing Na reabsorption in collecting duct
- Increase GFR by dilating afferent and constricting efferent arteriold
- ANP causes natriuresis and diuresis, redicing ECF
What does ADH to at kidney?
Same effect as aldosterone on distal tubule
opens up Na channels (ENaC)
What happens when you’re volume contracted?
What happens when you are hypervolemic (volume expansion)
