Adrenal Medulla Flashcards
What 2 overarching cell types are found in the adrenal medulla?
- chromaffin cells
- paraganglia
What are paraganglia?
small groups of nerve cells
Two chromaffin cell types
epinephrine + norepinephrine
_______ is essential for the development of the adrenal medulla.
neural crest
Neural crest gives rise to ________ which derives the adrenal medulla.
adrenal blasterna
Which hormone produced by adrenal medulla is primary? What percentage are each type?
epinephrine (primary - 80%)
norepinephrine (20%)
Give the order of the synthesis for production of catecholamines.
Tyrosine –> Dopa –> Dopamine –> Norepinephrine –> Epinephrine
(T/F) The production of norepinephrine can stop and does not have to continue and form into epinephrine.
True
What enzyme converts Tyrosine into Dopa in the synthesis of catecholamines?
tyrosine hyroxylase
What enzyme converts norepinephrine into epinephrine?
PNMT
What is the rate-limiting step in catecholamine synthesis?
tyrosine hydroxylase (tyrosine –> dopa)
What must be present to convert norepinephrine to epinephrine via PNMT?
cortisol
(Preganglionic/postganglionic) neurons of the (dorsal/ventral/lateral) horn of the spinal cord activate chromaffin cells to “dump” NE and E by releasing ________.
preganglionic
lateral
acetylcholine
_______ causes an increase in HR, while ________ causes an initial increase then decrease in HR.
epinephrine
norepinephrine
Which catecholamine increases force of heart contraction? What two effects follow?
epinephrine
increase cardiac output + BP
Describe the general effects that both epinephrine and norepinephrine have on the following systems:
- respiratory
- skeletal
- metabolic
- up RR and depth, dilate bronchioles
- increase contraction strength
- increase BG & FFAs, increase glycogenolysis/lipolysis, inhibit insulin
Match which action of catecholamines is true or false.
- dilate radial M of iris
- decrease GI motility
- decrease stomach sphincter contraction
- false - constrict (dilates eye)
- true
- false - increase
How do catecholamines affect glucose?
increase blood glucose
inhibit insulin directly
What 5 target receptors do norepinephrine and epinephrine use?
ALL adrenergic:
Beta 1
Beta 2
Beta 3
Alpha 1
Alpha 2
(T/F) Both norepinephrine and epinephrine can bind to adrenergic receptors but one may have a greater effect than the other.
True
What two enzymes are responsible for the degradation of catecholamines?
MAO
COMT
What is the main byproduct of catecholamine degradation? How is it removed from the body?
VMA (acid)
excreted in urine
Term for chromaffin cell tumor
pheochromocytoma
A pheochromocytoma leads to a(n) (excess/deficiency) of catecholamines.
excess
List 4 symptoms of pheochromocytoma
- hypertension
- panting
- tachycardia
- muscle wasting
An overproduction of catecholamines within and outside the adrenal medulla is a disorder called:
multiple endocrine neoplasia (MEN)
(T/F) There is an autosomal recessive genetic link to Multiple Endocrine Neoplasia.
False - autosomal dominant
(T/F) Multiple Endocrine Neoplasia is common in dogs but not cats.
False - neither is common
