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Flashcards in Adrenal gland Deck (53)
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1

cellular zonation of adrenal cortex

zona glomerulosa - mineralcorticoids (aldosteron)
zona fasiculata - glucocorticoids (cortisone, corisol, corticosterone)
zona reticularis- sex hormones (androgens, estrogens)
chromaffin cells - catacholamines ( NE & EPI)

2

Adrenal gland general function

affect blood pressure & electrolytes within the blood

3

Adrenal regulation

hypothalamus - CRH
pituitary gland - ACTH
adrenal cortex- cortisol feedback loop

4

precursor for adrenal gland hormones

cholesterol!

5

cortisol feedback mechanism

hypothalamus --(CRH)--> anterior pituitary --(ACTH)-->adrenal cortex--> cortisol!
cortisol inhibits hypothalamus & anterior pituitary

6

zona glomerulosa (outer 10%)

mineralcorticoids
aldosterone - enzyme aldosterone synthetase active
stimulated by ACTH & renin axis system

7

zona faciculata (middle 75%)

glucocorticoids - cortisol, cortisone, DHEA
stimulated by ACTH

8

zona reticularis (inner 10%)

androgens like DHEA are sulfated to DHEAS (main androgen)
stimulated by ACTH

9

Renin-angiotensin system (RAS)

renin is released from kidney juxtaglomerulus apparatus
renin acts on angiotensin-ogen from liver to get angiotensin I
angiotensin I is converted by ACE (lung) to angiotensin II ( vasoconstrictor)

10

what does Renin-angiotensin system (RAS) lead to in the body?

aldosterone release from adrenal cortex & resulting absorption of Na+ from the proximal tubule of the kidney
& increase in osmotic pressure & improvement of blood pressure

11

cortisol general

made in F-zone w/ adequate 17-alpha-hydrolase activity
dinural variation - regulated by ACTH
90% protein bound (CBG)

12

cortisol effects

stimulates gluconeogensis & glycogenesis
decreasing protein synthesis
increase blood glucose
decrease calcium absorption
increases adipose fat tissue
influences CNS pain perception & sense of well being
slows inflammatory response

13

cortisol & ATCH diurnal cycles

lowest at midnight & highest around 8 am

14

adrenal insufficiency labs show:

decreased cortisol
increased ACTH & CRH
the increased ACTH leads to adrenal gland hyperplasia & increased androgen production

15

Diseases associated with aldosterone

congenital adrenal hyperplasia
isolated hypoaldosteronism
hyperaldosteronism

16

diseases associated with cortisol

addison's disease
cushings syndrome

17

Congenital adrenal hyperplasia

inherited family of enzyme disorders
lead to decreased cortisol & decreased aldosterone
defect in 21-hydroxylase enzyme & causes a build up of 17-hydroxy progesterone & androgens bc cortisol is low
treat with replacement cortisol

18

isolated hypoaldosteroneism

only aldosterone is decreased
see in adrenal gland destruction, chronic heparin therapy etc
patients with diabetes, mild metabolic acidosis, increased metabolic acidosis & elevated serum K+ with low urinary K+

19

hyperaldosteronism

excess aldosterone
may develop metabolic alkalosis, hyper-tension & increased serum K+
determine PA/PRA (plasma aldosterone/plasma renin activity)
PA/PRA >25 indicative for disease

20

urinary excretion of K+ suggests:

hyperaldosteronism
especially >30 mEq/L

21

upright PA/PRA ratio (>25)

hyperaldosteronism

22

no Captopril suppression suggests:

hyperaldosteronism

23

Cortisol insufficiency

addisons disease
decrease cortisol w/ weakness, fatigue, anorexia, diarrhea, nausea
often 90% of cortex gland is destroyed

24

lab values for addison's disease

decreased Na+, glucose, cortisol
increased K+, ACTH, calcicum
prerenal azotemia
mild metabolic acidosis

25

causes of addisons

autoimmune (70%)
infections (tuberculosis 20%), hemorrhage, infiltrative processes, metastasis

26

cortisol insufficiency testing

when decreased cortisol w/ increased ACTH on 8 am specimen - need stimulation tests

27

Cosynthopin

stimulates both cortisol & aldosterone secretions
look for rise in cortisol when given 250 ug

28

Metyrapone

give at midnight, blocks 11-B-hydroxylase & look for rise in 11-DOC while cortisole decreases

29

normal response to cosynthopin but not to metyrapone?

look for secondary adrenal insufficiency (ACTH secreting tumor)

30

Addison's disease general

primary adrenal insufficiency - gradual destruction of adrenal gland
90% loss before symptoms
secondary adrenal insufficiency- most common form of the disease; Lack of ACTH