Flashcards in Adrenal Gland Phys Deck (52)
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1
Adrenal Gland composed of what two areas?
Cortex and Medulla
2
Adrenal cortex is located where in relation to the medulla
Periphery
3
What types of hormones does the adrenal cortex make?
Steroids
4
Three regions of the adrenal cortex
zona glomerulosa (15%)
zone fasiculata (75%)
zona reticularis (10%)
5
What does the zona glomerulosa make?
Aldosterone
6
What do the zona fasiculates and zona reticularis make?
Glucocorticoids (cortisol), SAndrogens and Estrogens
7
Adrenal Medulla makes?
Catecholamines (Epinephrine and Norepinephrine)
8
See slides and hormone table bs for function of the hormones
ok
9
Transport of adrenocortical hormones in blood is facilitated by what?
steroid hormone-binding serum proteins called GLOBULINS
-partially by albumin which has low affinity
10
90% of Cortisol exists in what form
BOUND, moslty to transcortin and partially to albumin
11
10% of cortisol in plasma is :
FREE
12
60% of aldosterone is bound to?
Transcortin
13
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
14
What is teh source of all steroid hormones
cholesterol duh.
15
What provides the cholesterol
LDL (80% cholesterol for steroid synthesis)
16
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
17
LDL is transported into the cells by what process
endocytosis (endosomal membrane trafficking)
18
In lysosomes cholesterol is released from the receptors
ok
19
Cholesterol is then esterified and stored in cytoplasmic vesicles until it is needed for steroid synthesis
ok
20
Key enzyme in steroid synthesis
KNOW
cholesterol desmolase (cyp11A1) part of the P450 superfamily
- facilitates the conversion of cholesterol to pregnenolone
21
What controls steroidogenesis
ACTH stimulates CYP11A1
- also stimulates cholesterol uptake by upregulating LDL receptors
22
Besides Desmolase, what is the other key enzyme in mineralocorticoid biosynthesis
Aldosterone Synthase
23
What upregulates desmolase activity?
ACTH...you know this
24
What upregulates aldosterone synthase
Ang II
25
What is the final step of mineralocorticoid biosynthesis?
corticosterone to aldosterone
26
Target organs for aldosterone
kidneys, brain, lungs, heart, vascular
27
What is the mechanism of mineralocorticoid effect?
Upregulates gene expression:
1) binds to MR's in the cytoplasm
2) The hormone receptor complex translocates to the nucleus
3) Binding to the promoter area of specific genes
4) Upregulation of gene expression (Na/K ATPase, Na, K transporters
28
Genes that are upregulated by the mineralocorticoids?
- Na/K ATPase...ATP dependent transport of Na and K
- Epithelial sodium channel (ENaC
- Serum and Glucocortocoid regulated kinase 1 (SGK1)
- Renal outer medullary K channel
---Important to note that SGK1 activates Na/K ATPase, ENac, and ROMK)
29
GLucocorticoids are produced where?
Zona Reticularis and Zona Fasiculata (main site of synthesis)
30
