Renal Week 1 - rest of week 1

Question 1

____% of body weight is fluid

Answer 1

60%, assume 70kg person = 42L

Question 2

ICF volume and contains

Answer 2

2/3 total

K, PO4, Mg, proteins

Question 3

ECF volume and contains

Answer 3

1/3 total

Na, Cl, HCO3, Ca

Question 4

Functions of kidney

Answer 4

ECF: volume, osmolarity, electrolyte, pH
Other: excretion
Blood pressure: water/Na and RAAS
EPO production
Gluconeogenesis
Vit D production

Question 5

ECF maintained by ________

Answer 5

urinary output

ingestion is in excess of insensible losses

Question 6

GFR =
Plasma flow =
NFP =

Answer 6

GFR = filtration fraction x renal plasma flow
GFR = k x NFP (k=pressure x SA)
Plasma flow = blood flow x hematocrit
NFP = (Pgc-Pt) - (πgc-πt), nml = 46-10-30-0

Question 7

Normal GFR rates in a 20 year old

Answer 7

Male: 120-130 mL/min
Female: 120-125 mL/min
Normal per lecture: 90-125 mL/min

Question 8

What accounts for decrease in GFR with glomerular dz such as diabetes or lupus?

Answer 8

Decreased in surface area leading to decrease of k (GFR = k x NFP)

Question 9

Normal FF, GFR, RPF

Answer 9

FF = 20%
GFR = 125 mL/min
RPF = 625 mL/min (1/5 CO)

Question 10

Myogenic response

Answer 10

Local (intrinsic) autoregulation of afferent arteriole

Maintains contant RBF and GFR with normal changes in MAP (75-150)

Question 11

Hypovolemia response

Answer 11

Drop in MAP that is extreme = sympathetic output to afferent arteriole (decreasing downstream)
RAAS activation = ATII to maintain GFR (close efferent)
PGE2/PGI2 released to open afferent

Question 12

Severe hypovolemia

Answer 12

Decreased πgc -> less driving force (equilibration sooner)

Decreased GFR, and increased FF

Question 13

Which nephrons create salt gradient in kidney?

Answer 13

Juxtamedullary nephrons

Question 14

Trace the blood flow in the kidney:

Answer 14

Renal artery, lobar arteries, arcuate arteries, interlobular arterioles, afferent arteriole, efferent arteriole, peritubular capillaries -> either vasa recta (covers pyramids) or vascular system to renal vein

Question 15

Role of the vasa recta

Answer 15

Descending: secrete water and absorb solute
Ascending: absorb water (Henle impermeable) secrete solute

Question 16

AKI and TGF

Answer 16

Prox damage -> more Na reaches distal tubule -> more afferent constriction -> slower GFR -> more time to absorb distally (but Ck builds due to slowing GFR, otherwise dump Na)

Question 17

Tubulo-glomerular feedback

Answer 17

Increased GFR -> less Na absorption in prox/loop -> increased delivery to distal -> increased macula densa/JGA -> increased constriction

Question 18

ECF volume is determined by _________. ECF osmolarity is determined by _________.

Answer 18

Sodium balance

H2O balance

Question 19

ECF volume clinical dx, sensors, effectors, response.

Answer 19

Physical exam. Stretch receptors. Aldo/ADH/vasoconstrictors etc. Renal Na absorption.

Question 20

ECF osmolarity clinical dx, sensors, effectors, response.

Answer 20

Lab tests. Osmoreceptors. ADH. H20 excretion/intake.