Urinary tutorial

Question 1

Functions of the kidney

Answer 1

Question 2

Renal vasculature

Answer 2

Resistance in nephrons are higher -> having capillary beds in series results in higher resistance
-Glomerular pressure is higher because you have 2 resistors in series

Question 3

The nephron

Answer 3

Tight junctions in nephrons prevent leaks and forces contents to move through the cell (free flow would not be regulated)

Question 4

Renal corpuscle

Answer 4

Question 5

Tubules of the nephron

Answer 5

Proximal tubule (PCT + PST) retrieves the largest portion of glomerular filtrate and has the leakiest epithelial junctions

Question 6

Juxtaglomerular apparatus (JGA)

Answer 6

Question 7

Glomerular filtration barrier

Answer 7

Question 8

Starling equation

Answer 8

Question 9

Forces affecting ultrafiltration

Answer 9

Question 10

Effects of arterioles on RBF

Answer 10

Question 11

Peritubular capillaries

Answer 11

Question 12

Net absorptive force

Answer 12

Question 13

Autoregulation of RBF

Answer 13

Question 14

Transport of glucose

Answer 14

SGLT1 couples 2Na:1 glucose -> cumulative thermodynamic gradient of Na and glucose generates high affinity for last 10% reabsorption of glucose in late proximal tubule

Question 15

Transport of amino acids

Answer 15

Question 16

Loop of henle

Answer 16

Descending limb: permeable to water, NOT NaCl -> filtrate concentrates in the medulla

Question 17

Countercurrent multiplier system

Answer 17

Question 18

vasa recta

Answer 18

-If vessels were straight, blood would absorb solutes and water and washout the hypertonicity necessary for creating concentrated urine

Question 19

Describe Na reabsorption

Answer 19

Question 20

Describe paracellular electrical coupling

Answer 20

Question 21

Describe furosemide as a loop diuretic

Answer 21

Question 22

How does urea assist in increased medullary hyperosmolality

Answer 22

Question 23

Explain modulation of osmotic pressure of urine

Answer 23

In absence of AVP, kidneys excrete hyposmotic urine (excess H2O)
-Increase in plasma osmolality and decrease circulating blood volume trigger posterior pituitary to release AVP in order to retain H2O

Question 24

Describe increase in water permeability by AVP

Answer 24

Triggers distal regions of nephron to become permeable to H2O, allowing H2O to flow down stepp osmotic gradient created by counter-current multiplier resulting in excretion of concentrated urine