Renal physiology: Loop of Henle

Question 1

how much sodium is absorbed

Answer 1

25%

Question 2

which type of drugs target the LOH

Answer 2

diuretics

Question 3

parts of the LOH

Answer 3

thin descending
thin ascending
thick ascendign

Question 4

thin segments

Answer 4

squamous epithelium
minimal metaoblic activity

Question 5

thick segments

Answer 5

cuboidal epithelium
metabolically active

Question 6

thin descending

Answer 6

highly water permeable
passive reabsorption via aquaporin 1 channels
small amount of urea and sodium reabsorbed
driven by the counter current multiplier

Question 7

thin ascending

Answer 7

impermeable to wate r
no aquaporin channels
Na+ reabsorption is passive through epithelial Na+ channels
Cl- reabsorbed through Cl- channels
some paracellular movement of Na+ and Cl- due to difference in osmolarity between tubule and interstitium

Question 8

thick ascending

Answer 8

primary sodium reabsorption
ipermeable to water
active reabsorption by Na+/K+ ATPase on basolateral membrane pumps Na+ out of the cell
low intracellular Na+ os inside of the cell is negatively charged
electrochemical gradeint
Na+ moves from tubular lumen down electrochemical gradient through NKCC transporter on the apical membrane
K+ back to the tubule by renal outer medulalry K+ channels on apical membrane
Cl- to tissues via CIC-KB channels
paracellular reabsorption of Mg, Ca, Na, K

Question 9

overall thick ascendign

Answer 9

removal of Na+ whilst retaining water
hypotonic solution in the DCT
Na+ into the intersitital space= hyperosmotic medulla

Question 10

counter current multiplication

Answer 10

thick ascending is impermeable to water
interstitium becomes concentrated with ions
increases osmolarity
drives water reabsorption from descending
water moves low osmolarity to high
allows kidnes to reabsorb around 99% filtered water