Flashcards in Endocrine Control of Body Fluid Volume Deck (49)
Where does the distal tubule end?
the collecting ducts
How much of the ion loads are reabsorbed?
what is the estimated residual load of NaCl?
What are the hormones that regulate ion and water balance?
What is the effect of ADH?
increased water absorption
What is the effect of Aldosterone?
increase Na absorption
increase K/H secretion
What is the effect of ANP?
decrease Na absorption
What is the effect of PTH?
increase Ca absorption
What does the distal tubule have a low permeability to?
water and urea
What does urea concentrated in the tubular fluid do?
establishes the osmotic gradient within the medulla
What are the two segments to the distal tubule?
early and late
What happens in the early distal tubule?
NKCC transport - Na Cl reabsorption
What happens in the late distal tubule?
What is the collecting duct split into?
early and late
What is the early duct similar to?
the late distal tubule
What happens in late collecting duct?
a low ion permeability
permeability to water influenced by ADH
When in ADH released?
when APs lead to Ca dependent exocytosis
What is the half life of ADH?
Where is ADH produced?
paraventricular nuclei in hypothalamus
What does ADH do in the distal tubular cell?
increases permeability of the collecting duct by inserting aquaporins
What is the effect of ADH on urine?
high water permeability = hypertonic urine 1400mosmol/l
How does the tubular fluid equilibrate with the interstitium?
What is true in the collecting duct?
impermeable to water so no water reabsorption in presence of minimal ADH
What does ADH do to urine osmolarity, volume and total solute excretion?
What happens in water deficit?
hypothalamic osmoreceptors detect increase in osmolarity and decreased Arterial blood pressure
What is diabetes insipidus or nephrogenic diabetes insipidus?
hereditary disease with large volumes of dilute urine and constant thirst
What is the treatment for diabetes insipidus?
What are some stimulants and inhibitory influences of ADH?
alcohol, stretch receptors in upper GI inhibits
When is aldosterone secreted?
in response to rising K or falling Na in blood
activation of the renin-angiotensin system