Adrenal Physio Flashcards
Cortex is derived from
secretes steroids in
AM secretes
Zona Reticulata secretes
Zona Fasciculate secretes
Zona glomerulosa secretes
mesoderm
zone specific manner
catecholamines
sex hormones
GC
aldosterone
Each zone of cortex expresses unique complement of ___, and has unique ____
MC fxn
Major controller
GC fxn
Major controller
Adrogen fxn
Mostly _____ from ZR
controlled by __ without NF
steroidogenic enzymes, regulatory/feedback
regulate salt/volume homeo
angiotensin 2
glucose,BP, immune homeo pituitary ACTH (POMC)
fetoplacental estrogen synth, peripheral androgen synth in women
DHEAS
ACTH
All adrenal steroids derived from
esterified cholesterol is stored in cytoplasmic
Transport of cholesterol from outer to inner mito membrane is ______ of steroidogenesis, requires ____ protein
first enzymatic rxn ___, converting ___ to prenenolone
occurs in ____, catalyzed by _____ a (CYP450)
this is the
free cholesterol
lipid droplets
rate limiting step of steroidogenesis, StAR
side chain cleavage, cholesterol
all 3 zones, CYP11A1
rate limiting enzyme
Expression of different ____ results in different hormones in zones
ZG expresses ____, to secrete
Cannot make ____ due to lack of ___
CYP17 can be a
ZF expresses ____ and ____
Produces _____
____ req for cortisol/aldo syn
ZR has _____
expresses _____ (SULT2A1)
Secretes _____ with some DHEA and androstenedione
CYP11B2, aldo
cortisol/androgens, CYP 17
OHase or lyase
CYP17 (OHase) and CYP11B1
cortisol
CYP21
CYP17 lyase
DHEA sylfotransferase
androgens (DHEA)
ZG regulation
stimuli sensed by kidney
result is to
promotes ____ and raised ____
AT2 stimulates release of
aldosterone inc ____, which inc renal H2O reabsorption, raising ____ and _____
Main target ____, along w
dec BP in renal AA, dec renal tubular Na or inc serum K
inc renin release, inc AT2
VC, BP
aldosterone
renal Na reabsorp, BP and K excretion
kidney, colon/salivary, sweat/gastric glands
Primary hyperaldo (Conns)
___ secreting tumor
____ retention, ___ depletion
Aldo deficiency leads to \_\_\_\_\_ wasting and \_\_\_ \_\_\_\_ cracing H H
aldo Na (HTN) and K loss (HypoK)
salt, dehydration
Salt
hypoTN
hyperK
Cortisol promotes survival during
maintains
CNS effect
actions independent of stress in
stress (exercise, fasting, dz etc)
blood glucose, BP
Memory/mood
bone, GI, skin, CT
Cortisol maintains BP by
Maintains BG by inc
dec
maintains normal C G, f B R G, inc M
ensuring normal vasc response to catechol
gluco, lipo, prot cat
glucose uptake
CNS fxn growth, fetal lung maturation bone remodeling Repro fxn GI fxn, appetite/GA sec muscle fxn/proteolysis
Cortisol maintains normal
immune
E
dec
at high levels, can have
has equal affinity for ____ , concentration is much greater than ____
In MC tissues, 11BHSD2 converts ____ to inactive cortisone
at high levels, cortsiol
GC responsive tissues express____, converting
homeostasis
EPO synthesis (RBC)
ADH sec/fxn
MC axns
MC receptor, aldo
cortisol
exceeds capacity of enzyme
11BHSD1, cortisone to cortisol
Cortisol is mainly
must be present at _____ for other hormones to fxn
helps to inc expression of ____ for other hormones
such as ____ in vasc SM
addtl mech
permissive
basal levels
receptors
adrenergic receptors
express coenzymes/co-factors
Circulating cortisol is regulated by
typically is bound to
Stress ____ CRH, inc
ACTH inc ___ by ZF
Cortisol provides NF to
HPA axis
CBG
inc, ACTH
cortisol synth/sec
CRH/ACTH
HPA Axis is controlled by
low levels in _____, high in
entrained by the ____ (can be reversed in night workers)
during stress, rhythm is maintained but
in dz
clinical diagnoses requires
circadian rhythm
pm/Am
sleep/wake cycle
levels elevated
rhythm dissappears
am/pm samples
Addisons dz (Hypocortisol)
primary adrenal insuff typically caused by
labs
sx H, O, A/G. D. no ____
Secondary AI caused by
labs
due to
AI destrxn of AC
low cortisol/aldo, high ACTH
hypogly in stress, ortho HypoTN, A/Gi dsyfxn, depression, no diurnal rhythm
pituitary hypofxn
low ACTH/cortisol, normal aldo
pituitary adenoma/infarct
Iatrogenic hypocortisol
Chronic (>3 wks) dec
this leads to atrophy of ____ bc CRH/aCTH are trophic
these regulate ____, dec ____
Abrupt withdrawal of exo cortisol leads to very weak ____ in ACTH/cortsiol bc
result
always ____ dose
CRH/ACTH
AC
pituitary/AC size/fxn, endo cortisol
inc ACTH/cortisol, tissues atrophy
hypocortisol
taper
AMSH is a cleavage product of ____ in the skin
does not occur in
AMSH ___ melanocytes, causing skin _____
high circ ACTH causes skin pigmentation bc
skin cells synthesizing MSH can cleave
POMC
AP
activates, pigmentation
ACTH can cross react w MSH receptor (MC1R) due to structural similarity
ACTH to AMSH
