Module 3A Flashcards
(49 cards)
What is the role of the adrenal gland in the endocrine system?
response to stress maintain salt/water equilibrium maintain BP Sympathetic function (extension of ANS)
What are the two regions of the adrenal gland?
Medulla and cortex
What does the adrenal cortex produce
Aldosterone, cortison, and DHEA
What does the adrenal medulla produce?
releases catecholamines - epinephrine and NE
What are the three layers of the adrenal cortex?
Zona glomerulosa (outer), Fasiculatat (middle), and zona reticularis (inner)
What is the difference between outer, middle and inner adrenal cortex?
Zona glomerulosa (outer) produces/secretes: Mineralcorticoid (aldosterone Zona Fasiculata (middle) and Zona reticularis (inner) both produce/secrete: Glucocorticoids (cortisol) and Adrenal androgen (DHEA)
What is the precursor for adrenal cortex
Cholesterol
What is step 1 in adrenal cortex hormone synthesis?
Cholesterol is converted to prenenolone
What is required to initiate the first tep of AC hormone synthesis?
ACTH and enzyme desmolase
What is the rate limiting step in AC hormone synthesis?
Cholesterol transportation across cell membrane is rate limiting step
What is the cascade pathway for AC hormone synthesis?
Stimulate, synthesize, release
What are the end products of AC hormone synthesis?
aldosterone, cortisol of DHEA
t/f hormones are not stored they are synthesized dependent on rate of demand (circadian rhythm)
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What is the stimulus for production of AC hormones?
hypothalamus releases CRH
CRH stims anterior pituitary to release ACTH
ACTH stimulates desmolase to convert cholesterol to pregnenolone.
What inhibits the production of AC hormones?
Increased levels of cortisol.
What makes cortisol an ideal negative feedback mechanism?
Initial steps of each AC hormone pathway are capable of producing cortisol. So very efficient
what is the stimulus for cortisol secretion?
ACTH released from anterior pituitary
Normal circadian rhythm
Stress stimulates release of ACTH
What inhibits the release of cortisol secretion?
elevated levels of cortisol inhibit ACTH and CRH
Negative feedback loop
What is the function of cortisol
a. in regards to glucose?
b. in regards to mineral corticoid receptors?
c. Pharmaceutically?
a. Elevates blood glucose
b. maintains fluid volume
c. Modulates immune system
What tissues does cortisol adversely effect?
Bone Muscle CT/Tendon Immune system CNS
What tissue does cortisol positively effect?
Fat cells liver decreased inflammation fetal lung development stress
Where is aldosterone produced?
Zona glomerulosa (outer)
What is the primary function of aldosterone?
Increase blood volume/BP by increasing renal sodium resorption (primary)
Decrease plasma potassium
Increase plasma pH (more alkaline)
What are the three actions of aldosterone?
- Increase sodium resorption in distal nephron
- Sodium resorption leads to cascade of other events : potassium excretion, and hydrogen excretion
- Vasoconstriction