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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

most potent glucocorticoid

Cortisol (hydrocortisone)...95% os glucoccorticoid activity