Overview of Renal Structure and Function

Question 1

Na+ is restricted to (intracellular or extracellular space)

Answer 1

extracellular space

Question 2

What determines the size of the extracellular fluid volume (ECFV)?

Answer 2

Total body Na content

Question 3

The ECFV determines …

Answer 3

BP and blood volume

Question 4

What determines osmolality?

Answer 4

Na

Question 5

How does an inc in total body Na affect the kidneys? (what are the chain of event this sets off?)

Answer 5

Na inc causes and inc in osmolarity –> stimulates thirst

Inc water intake stimulates secretion of vasopressin –> tells the kidneys to conserve water

Question 6

What determines the size of total body water?

Answer 6

Na

Question 7

What % of the male body is water? female?

Answer 7

males: 60%
females: 50%
* diff due to lower skeletal muscle mass

Question 8

What is the major buffer of the ECFV?

Answer 8

bicarbonate

Question 9

What is the normal pH of blood ?

Answer 9

7.4

Question 10

What minerals does the kidney maintain homeostasis for?

Answer 10

Ca, phosphorus, and Mg

Question 11

What waste material does the kidney get rid of?

Answer 11

urea (from protein metabolism)
creatinine (from muscle metabolism)
uric acid (from breakdown of nucleic acids)

Question 12

What are the endocrine functions of the kidney?

Answer 12

production of

1. EPO
2. active form Vit D/calcitrol (1, 25 (OH)2D3)
3. Renin
4. Bradykinin
5. prostaglandins (esp PGI2, PGE2)
6. endothelial factor (NO, endothelin)

Question 13

PGI2 and PGE2 vasocontrict or vasodilate?

Answer 13

vasodilate

Question 14

Endothelin vasocontrict or vasodilate?

Answer 14

vasoconstrict

Question 15

Specifically what/where in the kidney makes renin?

Answer 15

juxtaglomerular apparatus in the afferent arteriole

Question 16

What is renin?

Answer 16

catalytic enzyme that starts off the angiotensin-aldosterone cascade

Question 17

What are the 3 ways the kidney controls BP?

Answer 17

1. homeostasis of Na, H2O, ECFV
2. control of renin-angiotensin-aldosterone axis
3. production of vasodilatory substances

Question 18

What is the renin-angiotensin-aldosterone axis and what is the kidney’s role with it?

Answer 18

-regulates BP
-Kidney makes renin which sets off cascade –>
Angiotensin II is a potent vasocontrictor. Aldosterone promotes Na reabs