Physiology

Question 1

Net filtration

Answer 1

GFR = Kf * Puf

Puf = Pgc - (Pbc + Onc (gc))

Question 2

Clearance

Answer 2

Cx=(Ux * V)/Px

Question 3

Filtration Fraction

Answer 3

FF = GFR/RPF

Question 4

Filtered Load

Answer 4

GFR * Px

Question 5

Free Water Clearance

Answer 5

Ch20 = V- Cosm

Question 6

Fractional Excretion

Answer 6

FEna = (Una * Pcr)/(Pna * Ucr)

Question 7

Anion Gap

Answer 7

Na - Cl - HCO3-

Question 8

Hyperkalemia

Answer 8

acidosis
ischemia
a-adrenergic agonist
heavy exercise
low sodium diet
lack of insulin
beta blocker

Question 9

Hypokalemia

Answer 9

epi - beta adrenergic agonists
insulin
diruetics

Question 10

Collecting duct secretion of K+

Answer 10

increased ECF concentration
Na+ reabsorption balanced by K+ entering lumen due to (-) lumen
luminal flow rate dilutes [K+], moves down concentration gradient
H+/K+ exchange
Aldosterone stimulates K+ secretion

Question 11

Countercurrent multipler

Answer 11

Henley’s loop, vasa recta, CD

Na/K/2Cl in TAL
Urea reabsorption by ADH stimulation

Increase RBF to vasa recta or inhibit loop transporter causes decrease renal medullary interstitial osmolarity and decrease concentrating ability

Question 12

Water diuresis

Answer 12

low ADH, high volume low solute urine

Diabetes insipidus, volume expansion
lower [solute] in medullary insterstitium

Question 13

ANP action

Answer 13

Goal: decrease systemic BP

increase GFR - dilates AA, constricts EA (more Na+ and H2O filtered/excreted)
Inhibits Na+ reabsorption in medullary CD
Suppress renin, aldosterone, ADH
systemic vasodilator

Question 14

Early Proximal Tubule

Answer 14

100% glucose (SGLT2), aa reabsorbed with sodium
Na/H exchanger - AngII and NE stimulated
PTH blocks Na/Phosphate cotransporter activity
New HCO3 generated

Question 15

Late Proximal tubule

Answer 15

Na/H counter transporter

Question 16

TAL

Answer 16

H20 impermeable
Na/K/2Cl transporter - loop diuretic target (furosemide)
-sets up + lumen charge = Na, K, Ca2+, Mg2+, NH2+ driven between cells

Question 17

Early Distal Tubule

Answer 17

H20 impermeable
NaCl absorbed
Thiazide diuretic target

Question 18

Late Distal Tubule/CD

Answer 18

H20 impermeable unless ADH activity
Salt/water balance fine tuning
A-intercalated - reabsorb K, H excreted (Aldosterone stimulated)
Principal cells - secrete K, ADH adds aquaporin 2

Question 19

• lumen potential in collecting duct

Answer 19

Cl- passively absorbed, K+/H+ secreted