Regulation Of Kidneys Flashcards
What is diuresis
Excretion of excess water as urine
No reabsorption
Which drugs help diuresis excretion
Diuretics
Which hormone causes collecting duct permeability to h20 for reabsorption
ADH/vasopressin
Where is ADH produced and stored
In supraoptic and paraventricular nuclei in hypothalamus
Stored in posterior pituitary
Explain the steps of collecting duct water reabsorption when ADH is released from posterior pituitary
ADH binds to the V2 receptor on baso lateral membrane
This causes activation of adenylate cyclase and more pka is activated via camp
Pka causes vesicles with aquaporin 2 channels to insert into the apical membrane
WTer is reabsorbed passively back to ecf / medulla
At what osm (high) is are osmoreceptors stimulated to release ADH to lower osm
280mosm
What is the effect of the release of ADH to lower the osm at plasma from 280 upwards
They decrease osm
Causes BV to increase
Apart from lowering osm/ increasing BV what is ADH importance
Vasoconstriction
What happens at baroreceptors/volume receptors when they detect low BP or BV
Stimulates the release of ADH via sensory neurones to the hypothalamus
To rectify low BV or BP
Which organs remove ADH
Liver and kidney
What % loss of BV detected by receptors triggers ADH release
10%
What is the thirst mechanism called which is stimulated when too high OSM causing retention via ADH
Lateral preoptic area
Which kinds of physiological things stimulate ADH release to increase water reabsorption
Stress
Exercise
Pain
Does alcohol inhibit or stimulate ADH
Inhibits which causes dehydration
Drugs are inappropriate stimuli to release of ADH five example why this causes drowning
MDMA stimulated the lateral preoptic thirst area alongside ADH release to cause too much water reabsorption
Why would stopping circadian release of ADH cause bed wetting
Usually the release of ADH happens at night which would cause less water excretion
What are the 2 types of diabetes associated with ADH deficiency/loss
Central - lack of ADH
Nephrogenic - nephrons can’t respond to ADH ie the vasopressin 2 receptors
Which action in the kidneys is stimulated for na reabsorption affecting BP and BV
Renin/angiotensin/aldosterone
Which cells at the dct produce renin in response to paracrine factors from the macula densa cells
Juxtaglomerular cells
What happens when renin is produced by juxtaglomerulsr cells
Renin allows production of angiotensin 1 from angiotensinogen
Angiotensin 1 turns into 2 via ace enzyme
This causes release of aldosterone from adrenal medulla
Aldosterone causes na reabsorption
Blood volume is restored
Which cells does aldosterone bind to to increase na and water reabsorption
Principal cells
What does binding to principal cells from aldosterone do
Causes transcription and translation which increases number of Enac channels on apical side
And na / k pumps increase on baso lateral side
Na and Cl both get reabsorbed
How is k excreted due to aldosterone action
Via romK channels
How do diuretics stop na reabsorption
Stop enac channels
