renal regulation

Question 1

what is largely controlling the volume and osmolarity?

Answer 1

Na reabosorption

Question 2

If I regulate osmolarity, what can I manipulate in the body to have the highest affect?

Answer 2

water reabsorption

Question 3

what are the main osmotic constiuents in the ECF?

Answer 3

Na and Cl

Question 4

increasing the sodium concentration of the plasma leads to the activation of what systems in a person with impaired adrenal glands?

Answer 4

increasing osmolality (Na) has the following effects:

1. JG cells release Renin->AG1->AG2
   
   1. AG2acts on
      
      1. act on the afferent and efferent arteriole
      2. increase H2O intake
      3. secrete aldosterone acts on principal cells of the CCT
         
         1. increases transcription of
            
            1. ENaC
            2. Na/K pump
      4. stimulates hypothalmus to secrete ADH
         
         1. see below
2. sympathetic stimulation of the ANS->JGA
   
   1. release Renin->more AG2
3. Osmolarity directily has an affect on the posterior pituitary to release ADH

this individual will have no contribution of H2O uptake from the DCT- no ENaC or ATPases. But will still have affects of ADH on the TAL and AG2 on the afferent and effernet arterioles

Question 5

Renin release leads to AG2 generation how does this regulate the blood volume?

Answer 5

High blood osmolarity = low blood volume

1. glomerulus
   
   1. increase afferent constriction and increase efferent constriction(a bit more)
      
      1. decreases renal flow(peritubular) and increases filtration
      2. increases peritubular capillary colloid osmotic pressure (more stuff inside of the peritubular space than the lumen) and decreases the capillary hydrostatic pressure (things are not sweeping through as fast)
         
         1. increases Na reabsorption
            
            1. increasing Na uptake
               
               1. ​increases H2O uptake
2. decreases vasa recta blood flow
   
   1. decrease loss of Urea
   2. medullary interstitium increase urea and decreases Na
      
      1. increases gradient for passive NaCl reabsoprtion by the thins ascending limb of henle
         
         1. increase loop reabsorption
            
            1. increase Na uptake
               
               1. ​increase H2O uptake

Question 6

How does the TGF(tubuloglomerular feedback) affect the flow of fluids through the glomerulus?

Answer 6

glomerular filtration rate is the key to the TGF

1. increase in GFR
   
   1. increases the afferent contraction- decreasing pressure
   2. How does do the TAL cells work?
      
      1. NKCC2 on the macula densa absorbs the Na at the same rate as the GFR. An increase in GFR=increase in intracellular macula densa
      2. Na intracellular of the macula densa cells increases the ATPchannels into the interstitum
      3. ATP->->ADP activating the Gprotein on extramesangial cells to release Ca
      4. Ca goes through GAP junction to smooth muscle causing contraction.
      5. also inhibits renin release in JGcells
2. decrease in GFR
   
   1. decreases until GFR of appropriate level occurs
   2. realeses renin releases

Question 7

diagram the renal consequences of and increase in RAA:AG2

Answer 7

Question 8

describe the renal consequences of and increase in RAA with regard to aldosterone. (not hyperkalemia)

Answer 8

in high osmolarity(Na, not K), AG2 is generated and stimulates release of the aldosterone from the zona glomerulosa of the adrenal cortex

1. aldosterone acts on the principal cells of the CCT
2. increases transcription of apical ENaC and basolateral NKpumps
3. increases in Na uptake from lumen->intracellularly->interstitum->H20 uptake
   
   1. what is not seen are the K channels on the apical side. The lumen becomes less positive drawing K through the channels which is lost in the urine

Question 9

There are a few potent vasodilators which one is released from the heart and what kind affects does it have on the kidneys?

Answer 9

1. increase in ICF-> increase in BP ->increase in ANP
   
   1. ANP- potent vasodilator operates to increase natriuresis in two ways:
      
      1. increases GFR
      2. decreases Na channels in the MCD
         2.

Question 10

how does decreased ECF influence a greater reabsorption of Na in the PT?

Answer 10

decreased ECF-> decrease in blood pressure -> decreases GFR -> release of renin from JG -> AG2 changes hemodynamics of pertubular capillaries** and **vasa recta-> greater PT reabosorption of Na.

Question 11

what induces aldosterone release and what does it act on?

Answer 11

1. AG2
2. hyperkalemia

Both cause same thing

• Na reabosrption by principal cells
• loss of potassium