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Flashcards in Adrenal Gland Phys Deck (52):
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

31

Corticosterone

modest potency

32

What are the key enzymes in cortisol biosynthesis that we should know

- cholesterol desmolase
- 11beta hydroxylase

33

What drug inhibits desmolase action?

ketaconazole

34

What drug inhibits 11beta hydroxylase action

Metapyrone and Etomidate

35

Glucoccorticoids (cortisol) affect on the liver

promotes gluconeogenesis from amino acids, mobilization of amino acids from muscle into blood

36

Cortisol on pancreas?

upreg insulin production

37

cortisol's affect on various organs?

Upregulate insulin resistance

38

KNOW that glucocorticoids stimulate protein catabolism in all organs except the liver

ok. This means that proteins are broken down to amino acids, you have more amino acids in the blood, decreased protein synthesis mean sloss of body wt. and immune function suppresed

39

Gluccocorticoids and fat metabolism

Promotes lipolysis, enhance mobilization and oxidation of fatty acids as an alternative enrgy source.
-Redistribution of body fat (paradoxical fat deposits in the body)

40

High doses of oral cortisol can lead to what?

Cushing's syndrome

41

What does Cortisol do to immune function

Suppresses it

42

EFFEcts of Cortisol on other tissues

notes

43

Describe transactivation and transpression as they apply to glucocorticoid effect on gene expression

transactivation- stimulation or repression of gene expression

transpression- suppression of genes via transcriptional factors

44

Adrenal sex hormones and males

weak effects

45

Adrenal sex hormones in women

The major Androgens (excess leads to suppression of gonadal function and masculinization) This is called adrenogenital syndrome

46

The hormones of the adrenal medulla are?

Epinephrine, Norepinephrine

47

What is the structure of epinephrine and norepinephrine?

amino acid derivatives (tyrosine)

48

Remember that the cells of the medulla are neuroectodermal in origin and therefore are modified neurons

ok

49

Targets of catecholamines?

heart, lungs, muscles, vessels

50

Hypothalamic pituitary adrenal axis does what?

manages tress response, energy usage, immune response, digestion

51

Corticotrophin releasing hormone stimulates the pituitary to secrete ACTH

ACTH stimulates the adrenal cortex to produce its hormones....KNOW

52

Cortisol initiates a negative feedback regulation by inhibiting the hippocampus, hypothalamus,and pituitary gland

ok