Regulation ECF and OSM

Question 1

Amount of intake from beverages? Food? Metabolism?

Answer 1

Beverages= 60%

Food= 30%

Metabolism= 10%

Question 2

Amount of output from feces, sweat, insensible loss, urine?

Answer 2

Feces= 4%

Sweat= 8%

Insensible= 28%

Urine= 60%

Question 3

What changes happen in intake/output balance with warm weather, exercise

Answer 3

Increase in sweat, loss via respiratory system, decrease urine

Question 4

What happens when you take in excess h2o?

Answer 4

ECF OSM decreases–> decrease ADH secretion–> decrease plasma ADH–> DECREASE tubular permeability to H2O–> Decrease H2O reabsorbe–> increase H2O excreted

Question 5

How does urine flow respond to 1200 mL H2O?

Answer 5

Plasma osmolarity decreases, urine flow rate increases promptly, and plasma osmolarity is corrected fairly quickly

Question 6

What happens to concentration gradient in loop of henle when flow through vasa recta is fast?

Answer 6

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

Question 7

What happens to urine flow rate when given 1200mL bolus of saline?

Answer 7

No significant change in plasma osmolarity, so there si little change in urine flow rate. Small bump about 2 hours later

Question 8

An ____ in GFR will increase filtered load of sodium

Answer 8

increase

Question 9

What do we regulate to control sodium levels?

Answer 9

Filtration and reabsorption

Question 10

What do you change to change filtration of Na?

Answer 10

GFR

Question 11

What % Na absorbed in proximal tubule?

Answer 11

67%

Question 12

What % Na reabsorbed in TAL?

Answer 12

25%

Question 13

What % Na absorbed in DT/CD?

Answer 13

4%- DT

3% CD

Question 14

What happens to GFR with salt and water loss? How does this happen

Answer 14

GFR decreases

Question 15

Where are barorecptors located in kidney? What do they release?

Answer 15

Located in afferent arteriolar vessel walls

Release renin.

Question 16

What are effects of activation of RAAS system?

Answer 16

• Angiotensin II goes to stimulate:
  
  1. sympathetic activity
  2. tubular Na, Cl reabsorption and K excretion.
     
     • h2o retention
  3. aldosterone secretion
  4. arteriolar vasoconstriction
  5. increase ADH
     
     • increases H2O reabsorption
• Overall effect
  
  • water and salt retention
  • effective circulating volume increases
  • perfusion of juxtaglomerular apparatus increases

Question 17

What influences the neurohumoral control of renal sodium reabsorption?

Answer 17

• Sympathetic nerves
• RAAS
• Aldosterone
• ANP

Question 18

What does increaes sympathetics cause in kidney?

Answer 18

• 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

Question 19

What does aldosterone do to distal tubule?

Answer 19

• open up Na channel on apical membrane
• increase number Na-K ATPase pumps on basolateral membrane
• Increase K secretion

Question 20

What effect does angiotensin II have on proximal tubule?

Answer 20

Increase aldosterone

vasoconstrict afferent and efferent arterioles, decreasing GFR

Increase amount of Na/H antiporter on lumen of proximal tubule

Question 21

What does ANP (or ANF) do in kidney?

Answer 21

• 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

Question 22

What does ADH to at kidney?

Answer 22

Same effect as aldosterone on distal tubule

opens up Na channels (ENaC)

Question 23

What happens when you’re volume contracted?

Answer 23

Question 24

What happens when you are hypervolemic (volume expansion)

Answer 24