4: reabsorption and secretion Flashcards
(30 cards)
in ____ ____, water and solutes can travel thru the tubular epi, either thru the __ route (thru cell memb) or the __ route (bt cells via tight jxn)
tubular resorption
transcellular
paracellular
in tubular resorption, water is always absorbed by ___ mechanism (osmosis)
passive
__ __ is the limit to the rate at which a solute can be transported during active reabsorption or secretion
transport maximum
some substances that are passively absorbed don’t demo a transport maximum, rate dep on other things, is then called __ __ transport
gradient time
transport type in which the rate dep on:
- electrochem gradient
- perm of memb to substance
- time the fluid containing the substance in tubule
gradient time
some actively transported substances can exhibit characteristics of gradient time transport , such as:
Na reabsorption in prox tubule
sodium transport in the PROX tubules obey __ __ transport principles
- greater [Na] in prox tubule, greater reabsorp rate
- slower flow rate, more Na reabsorbed
gradient time
65% of filtered water and Na are reabsorbed in ___ ___ before reaching the _ _ _
proximal tubule
loop of henle
thin descending segment
thin ascending segment
thick ascending segment
–are the three parts of the :
loop of henle
the THICK ASCENDING segment of loop of henle is made of thick epi cells and functions in active resorption of (3):
Na
Cl
K
transport mechanism found in the thick ascending part of loop of henle
sodium-hydrogen counter-transport (mechanism)
late distal tubule and cortical collecting tubule is composed of what 2 cell types
principal
intercalated
in late distal tubule & cortical collecting tubule, reabsorp of Na and secretion of K is controlled by ____
aldosterone
permeability to water in late distal tubule and cortical collecting tubule is dependent on __
ADH
hormone that increases water reabsorp in resp to dehydration
ADH
w/o ADH, distal tubule & collecting ducts aren’t v. permeable to ___, and we would excrete large quantities of __ ___
water
dilute urine
two net reabsorptive forces that FAVOR reabsorption
plasma colloid OP (32mmHg)
hydrostatic P in interstitium (6mmHg)
two net reabsorptive forces that OPPOSE reabsorption
peritubular hydrostatic P (13mmHg)
OP of the renal interstitium (15 mmHg)
net reabsorptive forces AND glomerular cap net filtration forces both =
10mmHg
Kf (filtration coefficient) influences movement of fluid across caps and involves ___ __ and ___ of the capillary
surface area
permeability
Kf x net reabsorptive forces =
reabsorption
-if peritubular capillary hydrostatic pressure is raised, reabsorption rate is ____. if it is lowered, reabsorption rate ___
decreased
increases
Na+ excretion in urine is called ____, and water excretion to reg BP is called __ __
- increases arterial P
- increase in urinary excretion of Na & H2O
natriuresis
pressure diresis
___ is secreted by the zona glomerulosa cells of adrenal corex, and regs Na reabsorption and K secretion
aldosterone
