Fluids, Clearance, Hemodyamics

Question 1

What percentage of body weight is water for M and F?

Answer 1

60% (M), 50% (F)

Question 2

What are the effective and ineffective osmoles?

Answer 2

effective - Na+, K+, anions, glucose. Ineffective - BUN, EtOH

Question 3

What is the normal range of osmolality?

Answer 3

275-295 mOsm/Kg

Question 4

What is the equation for total osmolality?

Answer 4

2*Na + glucose/18 + BUN/2.8 + EtOH/3.7

Question 5

What is the equation for effective osmolality?

Answer 5

2*Na + glucose/18

Question 6

What is the relationship between tonicity and ICF volume?

Answer 6

inverse

Question 7

What is a normal GFR for adults (M/F)?

Answer 7

males = 120+/-25 ml/min
females = 95+/-20 ml/min

Question 8

What % of cardiac output is renal blood flow?

Answer 8

20%

Question 9

What % of renal plasma flow is filtered?

Answer 9

~20%

Question 10

What is the equation for renal plasma flow (RPF)?

Answer 10

RPF=RBF*(1-hct)

Question 11

What are the equations for filtered and excreted load

Answer 11

filtered load = GFRP
excreted load = VU
p=plasma conc; u=urine conc

Question 12

What is the formula for clearance?

Answer 12

C=VU/P=excreted load / plasma conc

Question 13

When does clearance = GFR

Answer 13

when there is no secretion or reabsorption

Question 14

What are the two substances with perfect clearance?

Answer 14

inulin and creatinine

Question 15

What happens to creatinine when GFR decreases

Answer 15

slowly increases to reach steady state

Question 16

filtered load/excreted load of creatinine = ?

Answer 16

GFR * plasma conc

Question 17

What is used to estimate RPF?

Answer 17

para-amino hippuric acid (PAH)

Question 18

What is the extraction ratio for PAH?

Answer 18

0.9

Question 19

What is the equation for filration fraction?

Answer 19

FF=GFR/RPF

Question 20

What separates glomerular capillaries from Bowman’s space?

Answer 20

endothelial cells, basement membrane, podocytes

Question 21

What is the largest size of molecule that can be filtered in the glomerulus?

Answer 21

40 Angstroms

Question 22

What is the charge of the basement membrane?

Answer 22

negative

Question 23

Why is albumin not filtered?

Answer 23

negative charge

Question 24

Why does colloid osmotic pressure increase in glomerular capillaries?

Answer 24

loss of fluids and retention of proteins

Question 25

What keeps GFR steady when BP changes?

Answer 25

RAAS

Question 26

What happens to GFR, RPF, and FF when the afferent arteriole is vasoconstricted?

Answer 26

decrease, decrease, no change

Question 27

What happens to GFR, RPF, and FF when the efferent arteriole is vasoconstricted?

Answer 27

increase, decrease, increase

Question 28

What happens to GFR, RPF, and FF when the afferent arteriole is vasodilated?

Answer 28

increase, increase, no change

Question 29

What happens to GFR, RPF, and FF when the efferent arteriole is vasodilated?

Answer 29

decrease, increase, decrease

Question 30

What pressure is affected by urinary obstruction?

Answer 30

capsular hydrostatic pressure

Question 31

RAAS causes what change to the arterioles?

Answer 31

efferent constriction

Question 32

ACEi/ARBs cause what change in the arterioles?

Answer 32

efferent dilation

Question 33

What effect do prostaglandins have on the nephron?

Answer 33

afferent dilation

Question 34

What effect do NSAIDs have on the nephron?

Answer 34

afferent constriction

Question 35

What is defective in diabetes insipidus?

Answer 35

ADH