Renal Phys 4

Question 1

Renal Hemodynamics

Answer 1

dynamics of blood flow to the kidney, how its regulated, and how it influences filtration, systemic blood pressure, and blood volume

Question 2

Renal fraction

Answer 2

percent of cardiac output that is supplied to the kidney

Question 3

Whic arteriole is larger in diameter - afferent or efferent?

Answer 3

afferent

Question 4

Which arteriole has higher resistance - afferent or efferent?

Answer 4

efferent (but both are resistors)

Question 5

Effect of Changing Efferent Arteriole Resistance on GFR and RBF

Answer 5

increase efferent arteriole resistance
CHANGE IN OPPPOSITE DIRECTIONS
decrease RBF, increase GFR

Question 6

Effect of Changing Affferent Arteriole Resistance on GFR and RBF

Answer 6

increase afferent arteriole resistance
CHANGE IN SAME DIRECTION
decrease RBF, decrease GFR

Question 7

Intrinsic Regulators of RBF and GFR (2)

Answer 7

1. Myogenic Mechanism
2. Tubuloglomerular Feedback

Question 8

Extrinsic Regulators of RBF and GFR (7)

Answer 8

1. Systemic Nerves
2. RAAS
3. Natriuretic Peptides
4. Nitric Oxide
5. Prostaglandins
6. Bradykinin
7. Endothelin

Question 9

Myogenic Mechanism

Answer 9

senses changes in wall tension (blood pressure) in the affferent arteriole and adjusts as needed; fact (less than 10 seconds)

Question 10

Are there any nerves involved in the myogenic mechanism?

Answer 10

nope (no hormones either)

Question 11

Tubuloglomerular Feedback

Answer 11

juxtaglomerular apparatus senses flow (Salt Concentration (NaCl)) in distal tubule and ascending limb, feedback will alter vascular tone to either inc or dec time for NaCl to be absorbed therefore affecting RBF and GFR

Question 12

Juxtaglomerular (JG) cells

Answer 12

aka granular cells of afferent arteriole that synthesize and store renin, highly innervated, intra-renal baroreceptors

Question 13

Macula Densa cells

Answer 13

in distal convoluted tubule and act as chemoreceptors to sense changes in NaCl concentration

Question 14

Mechanism of Tubuloglomerular Feedback

Answer 14

macula densa sense high NaCl, results in release of adenosine, which binds to extraglomerular mesangial cells and increases calcium, which results in vasoconstriction of afferent arteriole (dec GFR) and inhibit renin release (dec GFR)

Question 15

Main target of sympathetic nerves in the kidney?

Answer 15

afferent arteriole

Question 16

Effect of Circulatory Shock on Kidney

Answer 16

nerves shut off blood flow to kidney and shunt it to heart brain and skeletal muscles resulting in renal shutdown

Question 17

What takes precedence in instances of severe fluid loss - sympathetic nervous system or renal autoregulation?

Answer 17

sympathetic nervous system

Question 18

Does RAAS require innervation?

Answer 18

no

Question 19

Natriuretic Peptides

Answer 19

ANP (atrial) and BNP (brain), secreted in instances with increased ECF (like heart failure); opposes RAAS and inhibits renin release

Question 20

RAAS

Answer 20

just look at it again

Question 21

Prostaglandins

Answer 21

made in kidney and released in response to decreased ECF (ex hemorrhage) to vasodilate arterioles in the kidney

Question 22

NSAIDs and kidney toxicity

Answer 22

increases release of prostaglandins!

Question 23

Nitric oxide

Answer 23

dilates the arterioles in the kidney

Question 24

Bradykinin

Answer 24

increases synthesis of nitric oxide

Question 25

Endothelin

Answer 25

vasoconstricts arterioles in the kidney, present during renal disease