17. Renal physiology

Question 1

Distribution of Renal Blood flow Between Cortex and Medulla

Answer 1

Cortex vs medula
Percentage of renal blood flow 94
Blood flow (mL/min/g) 5.0 vs 0.03
PO2 (mm Hg) 50 vs 8
O2 extraction ratio (VO2/DO2) 0.18 vs 0.79

Question 2

Renal vasodilator Systems

Answer 2

Prostaglandins
Kinins
Atrial natriuretic peptide
Increase RBF GFR Urine flow Na excretion

Question 3

Vasoconstrictor
Systems (renal)

Answer 3

Sympathoadrenal system
Renin-angiotensin system
Aldosterone
Antidiuretic hormone (ADH)
Decrease RBF GFR Urine flow Na excretion

Question 4

Where in the kidney does most of the reabsorption of water take place
Where it doesnt at all

Answer 4

Proximal tubule
Not at all in Thick ascending

Question 5

Where does take action in the kidney…
Fusid, K sparing ADH

Answer 5

Fusid Loop of Henle
K sparing Distal tubule
ADH collecting tube

Question 6

Osmolarity formula

Answer 6

2xNa + 2xK + BUN/2.8 + Gluc/18

Question 7

CO to the kidneys

Answer 7

20%

Question 8

Acute Kidney injury and MAP

Answer 8

MAP less than 55, 10 min
MAP less than 60 11-20 min

Question 9

reason for angioedema

Answer 9

Renal kininase (inhibited by ACE inh)

Question 10

Attenuated the
increase in serum creatinine…

Answer 10

desflurane, sevoflurane, isoflurane, and halothane

Question 11

Kidney characteristics

Answer 11

CO 20%
VO2 7%
2 capillary beds. Vasa recta + Glomeruli

Question 12

Kidney region more sensible for ischemia

Answer 12

the metabolically active medullary thick ascending loop of Henle

Question 13

Adrenergic stimulation of kidneys, RBF and GFR

Answer 13

Mod increase RBF and GFR
Severe Decrease both

Question 14

Urinary output

Answer 14

Oliguria. < 0.5, not a modifiable risk to death, good indicator for renal dysfunction

Question 15

BUN in non kidney disease

Answer 15

Increase in Sepsis, steroids, GI bleeding
Decrease in liver disease

Question 16

Induced hypotension and kidney

Answer 16

Fenoldopam is capable of
providing induced hypotension
without any significant decrease in RBF
Nicardipine increased creatinine clearance
Nitroglycerin decreases RBF less than sodium nitroprusside