Lecture 63 - Endocrine 5 Flashcards
what organ produces adrenaline/epinephrine
adrenal glands
what is the deepest and outermost structure of the adrenal gland
medulla; cortex
the adrenal medulla produces
catecholamines (epi- and norepi-)
the zona glomerulosa produces
mineralocorticoids (aldosterone) - salt regulation
the zona fasciculata produces
glucocorticoids (cortisol) - sugar control
the zona reticularis produces
androgens (sex hormones)
T/F: the adrenal medulla is innervated by preganglionic sympathetic fibers
TRUE
what is stimulus-secretion coupling
- arrival of stimulus at cell surface receptors
- secondary messenger system is triggered
- release of transmitter
describe epinephrine synthesis
- tyrosine to DOPA via tyrosine hydroxylase
- DOPA to dopamine
- dopamine to norepinephrine
- norepinephrine to epinephrine
what is the rate-limiting step in epinephrine synthesis
tyrosine to DOPA
what enzyme is used to convert tyrosine to DOPA
tyrosine hydroxylase
describe corticosteroids (composition, receptor location, post-cell response, transport)
composition: cholesterol
receptor location: intracellular
post-cell response: altered gene transcription
transport: proteins
what hormones stem from cholesterol
- aldosterone
- mineralocorticoid
- glucocorticoid
- androgens
- estrogen
what is needed for the hydroxylation of C17
17-alpha-hydroxylase
T/F: cortisol is synthesized in the zona glomerulosa
FALSE
adrenocortical hormones differ by a hydroxyl group on which carbon atom
C17
what two events will lead to catecholamine release
- stressful events (fast and large)
- hypoglycemia
Alpha 1 receptor does what
stimulatory
vasoconstriction
sm. muscle contraction
Alpha 2 receptor does what
inhibitory
inhibits CNS effects and insulin release
pain-relief
Beta 1 receptor does what
affects heart
increases rate and contractility
Beta 2 receptor does what
affects lungs
sm. muscle relaxation
metabolic
skeletal muscle perfusion
T/F: catecholamines interact with adrenergic receptors
TRUE
A 10y/o castrated male dog presents with acute ataxia. there is a cerebellar lesion, tachycardia, and hypertension. where is the most likely place for a tumor? what hormone is being produced in excess?
adrenal gland; catecholamines
T/F: hyperglycemia is a stimulus for epinephrine
FALSE
what are the major effects of aldosterone
sodium resorption
potassium excretion
increased blood volume and blood pressure
how does aldosterone interact with the kidney
stimulates sodium resorption and potassium secretion
what are the 3 stimuli for aldosterone release
- angiotensin II
- increased plasma potassium concentrations
- increased ACTH
a 12y/o castrated male cat presents for severe muscle weakness (recumbent, marked ventroflexion of neck), blood potassium is severely low, and hypertension. where is the tumor most likely? what hormone is being produced in access?
adrenal gland; aldosterone
which electrolyte disturbance stimulates aldosterone secretion
hyperkalemia (high phosphate)
this hormone inhibits aldosterone secretion
ANP
