1) All of the following are mechanisms of renal autoregulation of GFR EXCEPT : a

Question

1) All of the following are mechanisms of renal autoregulation of GFR EXCEPT:

a. sympathetic stimulation of afferent arterioles

b. the action of angiotensin on afferent and efferent arterioles

c. the action of NP on mesangial cells

d. vasoconstriction in response to stretching of afferent arteriole walls

e. secretion of ADH in response to increased osmolarity of blood

2) Sodium ion transporters in the proximal convoluted tubule promote the reabsorption of All of the following EXCEPT:

a. ammonium ions

b. bicarbonate ions

c. chloride ions

d. glucose

e. amino acids

3) An increase in blood pressure in the afferent arterioles of the kidney will result in All of the following EXCEPT:

a. a decrease in the relase of atrial natriuretic peptide

b. an increase in glomerular filtration rate

c. an increase in glomerular hydrostatic pressure

d. a somewhat greater outpu of urine

e. a decrease in release of renin by juxtaglomerular cells

4) Blood in the renal vein may have a higher concentration of bicarbonate ions than blood in the renal artery because:

a. bicarbonate ions cannot pass the glomerular filter, so blood becomes more concentrated as water eners the nephrons and bicarbonate ions stay behind.

b. the rate of celular respiration is higher in the endothelium of he renal venules than in the endothelium of the renal arterioles

c. newly produced bicarbonate ions (as opposed to filtered bicarbonate ions) are added to the blood by he intercalated cells of the collecting ducts as they secrete hydrogen ions into the tubular fluid

d. hydrogen ions must be added to the venous blood to maintain pH balance, so bicarbonate ons are reabsorbed at the same time to maintain elecrical balance

e. large ions like bicarbonate ions are necessary in the venous blood to help maintan blood colloid osmotic pressure

Explanation / Answer

Question 1

Answer is E

The quantity of filtrate produced in each kidney per minute is called Glomerular Filtration Rate.

The GFR is regulated by different mechanisms,

i. neuronal regulation.

In this the sympathetic stimulation regulates GFR.

ii. autoregulation.

- Myogenic regulation - it regulates through stretching of blood vessels of afferent arterioles

- Tubular regulation.

iii. Hormonal regulation

Regulated by action of Natriuretic peptides on mesangial cells

By the action of angiotensin of afferent and efferent arterioles.

So the secretion of ADH in response is not involved in autoregulation of GFR.

Question 2

Answer is A

The ions reabsorbed along with sodium ions are

in the first part of proximal convoluted tubules are glucose, amino acids, phosphates and sulfates and lactic acid

The ions reabsorbed in the second part of proximal convoluted tubule are chloride ions, bicarbonates, urea, and magnesium.

The ammonium ions are secreted from proximal convoluted tubule.

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