Adrenal Cotex/Medulla (lec 25) Flashcards
Adrenal glands regulate? (6)
Fluid/mineral balance Electro balance Energy Tissue injury response Stress survival CV tone
Mineralcorticoids are?
Secreted from?
hormones that regulate salt/H2O retention in kidney
e.g. aldosterone
Zona glomerulosa
Glucocorticoids are?
Secreted from?
hormones that regulate plasma glucose
e.g. cortisol
Zona fasciculata
Androgens are?
Secreted from?
sex hormones
e.g. DHEA, androstenedione
Zona reticularis
Adrenal Medulla made of what type of cells?
Secrete what?
chromaffin
Epi»_space; Norepi
Adrenal Cortex hormes made from?
cholesterol
Steroid hormone synthesis?
Cholesterol Δ to steroid in organ-specific rxn
Hormone NOT stored (used up at time of synth)
Adrenalcortical Hormones: route of synth?
Hypothal: Corticotropin-Releasing Hormone (CRH) ->
Ant Pit cortitrophs: Adrenocorticotropic Hormone (ACTH) ->
Adrenal Cortex:
activates cholesterol desmolase
Steroid synth precursor?
cholesterol
Steroid synth Step 1?
cholesterol + desmolase -> pregnenolone
Cortisol is?
glucocorticoid produced in zona fasciculata
Enzymes needed for Cortisol syth are found where?
in the z. fasc
Cortisol feedback regulation?
cortisol directly inhibits release of CRH and ACTH
ACTH stimulates release of more CRH
ACTH effects? (2)
1) Activate cholesterol desmolase
2) Stim adrenal gland growth
Cortisol released in response to?
Purpose?
stress
↑ glucose for CNS use
Cortisol ↑ blood glucose how?
↑ protein catabolism -> AA release
↑ lipolysis -> ↑ glycerol
↓ tissue uptake of glucose
↑ gluconeogenesis
Aldosterone is?
major mineralocorticoid
Aldosterone synth: where?
z glomerulosa
Aldosterone synth: route?
Same thru pregnenolone but NO 17-a-hydroxylase ->
Progesterone to corticosterone ->
+ aldosterone synthase (A via AngII) ->
aldosterone
Why doesn’t z glom produce glucocorticoids/androgens?
does not have 17⍺ hydroxylase
Aldosterone purpose?
regulate ECF vol via Na+ exc/reab
Aldosterone released in response to?
↓ ECF, ↓ BP (Ang II)
↑ plasma K+
Aldosterone results in?
Na+ reab
K+ excr
Expansion of ECF
Androgens are?
sex hormones
Androgens synth where?
z reticularis
Androgens synth route?
Same thru 17-hydroxypregnenolone ->
17.20 Lyase -> Androstenedione
Adrenal Androgens most important for?
major source of androgens for females
Cushing’s disorders caused by?
excess glucocorticoids and androgens
Cushing’s Syndrome from?
Sxs?
Primary adrenal hyperplasia
thin skin mm wasting/protein wasting central obesity round face buffalo hump hyperglycemia HTN virilization (male characteristics)
↓ ACTH
↑ cortisol
Cushing’s Disease from?
Sxs?
overactive ant pit -> excess ACTH
same as syndrome
↑ ACTH
Addison’s Disease from?
primary adrenocortical insuff/autoimmune destruction of gland =
↓ synth of all adrenocortical hormones
Addison’s Dz sxs if ↓ cortisol?
hypoglycemia, anorexia, wt loss, weakness
Addison’s Dz sxs if ↓ aldosterone?
hyperK+, hypoTN, acidosis, salt craving
Addison’s Dz sxs if ↓ androgens?
Females: ↓ pub/ax hair, ↓ libido
2º Adrenocortical Insuff caused by?
↓ CRH or
cortitrophs Φ secrete ACTH
Aldosterone levels U normal
2º Adrenocortical Insuff sxs?
same as low cortisol/androgens
Conn’s Syndrome caused by?
Aldosterone hypersecretion (tumor)
Conn’s Synd results in?
↑ Na+ reab -> hyperNa+/hypervol/HTN
↑ K+ secr -> hypoK+
↑ H+ secr -> meta alkalosis
↓ renin
Androgenital Syndrome caused by?
hypersecretion of adrenal androgens
Androgenital Synd sxs?
(from ↑ androgens)
Females w/ male traits
21 β-hydroxylase Deficiency cased by?
Cortex Φ sythn glucocort or mineralocort
21 β-hydroxylase Deficiency results in?
steroids buildup -> Δd to androgens ->
androgenital synd
High ACTH due to Φ feedback control in pit
17 ⍺-hydroxylase Deficiency caused by?
Cortex Φ sythn glucocort or andorgens
17 ⍺-hydroxylase Deficiency results in?
steroids buildup -> Δd to mineralcort
Low aldosterone due to HTN from high corticosterone (HTN ↓ renin)
Adrenal Medulla innervation?
Sympathetic
Medulla purpose?
secrete epi/norepi
Rapid mediation of fuel metabolism
Release glu and FFA during stress
Stim CV
Reg vascular sm mm fxn
Epi/Norepi synth where?
Regulated by?
Adrenal medulla
Symp stim
Acute Symp stim of medulla results in?
activates tyrosine hydroxylase
Chronic symp stim of medulla results in?
↑ [tyrosine hydroxylase]
Cortisol affects Epi/Norepi synth how?
activates phenyl-N-methyl
Epi purpose for metabolism?
mobilize/produce glucose for CNS during stress
Epi effects on skeletal mm and liver?
↑ glycogenolysis
Epi effects on fat?
↑ lipolysis
Epi effects on CV?
↑ contract ↑ HR ↑ conduction ↑ BP ↑ arteriolar vasoconst (renal, splanchnic, cutaneous)
Epi other effects?
bronch dila
pupil dila
↓ GI
↑ alertness
