Loop of Henle

Question 1

what does the liver do to lipid soluble drugs and pollutants to facilitate their excretion

Answer 1

makes them polar (water soluble)

guess this makes it easier for them to be secreted and excreted from osmotic pressures etc

Question 2

fluid in proximal tubule is iso/hypo/hyper osmotic to plasma

Answer 2

isosmotic

Question 3

what is the osmolarity of plasma

Answer 3

300mOsmoles/L

Question 4

how are do proximal tubule and plasma have the same osmolarity

Answer 4

because all movements have been accompanied by H20 movements

Question 5

where are the proximal and distal tubules, cortex or medulla

Answer 5

cortex

Question 6

what does the loop of henle do

Answer 6

concentrates urine

Question 7

what is the minimum concentration of urine that can be produced

Answer 7

30-50mOsmoles/L (10 times weaker than plasma)

Question 8

which loops of henle establish a hypertonic medullary gradient

Answer 8

ones in the medulla. i.e. belonging to juxtamedullary nephrons

Question 9

which limb of henle loop is impermeable to H2O

Answer 9

ascending limb

Question 10

permeabilities of descending limb

Answer 10

H2O permeable

NaCl impermeable

Question 11

which limb of henle loop is impermeable to NaCl

Answer 11

descending limb

Question 12

which limb of henle loop is permeable to NaCl

Answer 12

ascending limb

Question 13

effect of ascending limb on concentration

Answer 13

reduces concentration (pumps out NaCl)

Question 14

which limb of henle dilutes the fluid

Answer 14

ascending

Question 15

which limb of henle concentrates the fluid

Answer 15

descending

Question 16

when water moves out of descending limb into interstitium where does it go from there

Answer 16

it is reabsorbed into the vasa recta by oncotic pressure

Question 17

once water moves out of descending limb into interstitium where does it go from there

Answer 17

it is reabsorbed into the vasa recta by oncotic pressure

Question 18

describe the process of concentration in the loop of henle

Answer 18

ascending limb actively pumps out NaCl making the interstitial fluid more concentrated and the tubule more dilute.
the descending limb dilutes the interstitial fluid by moving out water.
but the ascending limb just keeps on pumping out more and more salt and the descending limb keeps on losing water to it.
fluid is most concentrated at end of descending.

Question 19

if the active transport of NaCl doesn’t happen what is the conc of urine like

Answer 19

isotonic i.e. 300mOsmoles/L

Question 20

what’s more dilute, distal tubule or plasma

Answer 20

distal tubule (100 compared to 300)

Question 21

effect of loop of henle on interstitium

Answer 21

it makes it increasingly concentrated

Question 22

what difference exist between the limbs at the same horizontal level

Answer 22

200mOsmole/L

Question 23

what is the vasa recta

Answer 23

arrangement of peritubular capillaries of juxtamedullary nephrons

Question 24

true/false capillaries are only freely permeable to H2O giving them a different osmolarity to the interstitium around them

Answer 24

false - they are freely permeable to all solutes and H2O and so equilibrate with interstitium

Question 25

true/false vasa recta interfere with interstitial gradient

Answer 25

false - they do not disturb it

Question 26

3 functions of vasa recta

Answer 26

1. provide O2 for medulla
2. not disturbing gradient
3. remove volume from interstitium

Question 27

vasa recta has high/low flow rate

Answer 27

low flow rate - allows time for equilibration to occur

Question 28

where is water regulated

Answer 28

collecting duct

Question 29

what hormone control water regulation

Answer 29

Anti-Diuretic Hormone (Vasopressin)