Adrenal Gland Phys Flashcards
Adrenal Gland composed of what two areas?
Cortex and Medulla
Adrenal cortex is located where in relation to the medulla
Periphery
What types of hormones does the adrenal cortex make?
Steroids
Three regions of the adrenal cortex
zona glomerulosa (15%) zone fasiculata (75%) zona reticularis (10%)
What does the zona glomerulosa make?
Aldosterone
What do the zona fasiculates and zona reticularis make?
Glucocorticoids (cortisol), SAndrogens and Estrogens
Adrenal Medulla makes?
Catecholamines (Epinephrine and Norepinephrine)
See slides and hormone table bs for function of the hormones
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Transport of adrenocortical hormones in blood is facilitated by what?
steroid hormone-binding serum proteins called GLOBULINS
-partially by albumin which has low affinity
90% of Cortisol exists in what form
BOUND, moslty to transcortin and partially to albumin
10% of cortisol in plasma is :
FREE
60% of aldosterone is bound to?
Transcortin
Purposes of hormone binding protein:
- suppress the biological activity of steroid hormones
- protect the hormone from structural alteration
- Extend the half-life of hormones
- Provide an active hormone to the target tissue when needed
What is teh source of all steroid hormones
cholesterol duh.
What provides the cholesterol
LDL (80% cholesterol for steroid synthesis)
How cholesterol get into adrenal cells for steroid synthesis
LDL binds to LDL receptors (clathrin coated pits) on the plasma membranes of adrenal cortical cells
LDL is transported into the cells by what process
endocytosis (endosomal membrane trafficking)
In lysosomes cholesterol is released from the receptors
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Cholesterol is then esterified and stored in cytoplasmic vesicles until it is needed for steroid synthesis
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Key enzyme in steroid synthesis
KNOW
cholesterol desmolase (cyp11A1) part of the P450 superfamily - facilitates the conversion of cholesterol to pregnenolone