ADH Flashcards
What is ADH?
It is a 9 amino acid peptide
Where is ADH synthesized?
Hypothalamus
Where is ADH secreted from?
Posterior pituitary
What 2 things affected by ADH?
Osmoreceptors
Baroreceptors
Osmoreceptors
Sensitivity?
Big or small?
Activates?
Very sensitive (detect changes in osmolality on a minute to minute basis) - detect 1 to 2% changes in osmolarity
Small
Activate ADH
Baroreceptors
Sensitivity?
Big or small?
Activates?
Insensitive
Large
Activate ADH
What do osmoreceptors detect?
Drink lots of water
What happens when u drink lots of water?
Decrease plasma osmolarity Decreased firing by hypothalamic osmoreceptors ADH release inhibited Decrease plasma ADH Increased water excretion at LOH and CD
ADH has a short half life of ….
15 mins
Adapt quickly to osmolarity changes
As well as affecting the collecting ducts, what does ADH also do to restore BP?
Arteriolar constriction
What substances affect vasopressin secretion?
Alcohol - decrease it, dehydration
MDMA- increase secretion
Nicotine - increase secretion
What do Baroreceptors detect?
Decreased ECF volume
What happens when ECF volume decreases?
increased Baroreceptor firing
ADH release stimulated
Increased plasma ADH
Decreased water excreted at LOH and CD
