The Adrenal Hormones Flashcards Preview

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Flashcards in The Adrenal Hormones Deck (54):
1

Where is the adrenal gland?

On top of the kidneys
Triangle shape

2

What is the adrenal gland made up of?

Adrenal cortex
Adrenal medulla

3

What does the adrenal gland do?

Secrete different types of hormones

4

What type of compounds do the adrenal cortex secrete?

Steroid compounds

5

Give some examples of the steroid compounds produced by the adrenal cortex?

Glucocoticoids e.g. cortisol
Mineralocorticoids e.g. aldosterone
Sex hormones e.g. testosterone

6

What type of compounds do the adrenal medulla secrete?

Catecholamines

7

Give some examples of the catecholamines produced by the adrenal medulla?

Epinephrine (adrenaline)
Norepinephrine (noradrenaline)

8

What happens in zone glomerulosa in the adrenal cortex ?

Secretion of aldosterone

9

What happens in zone fasiculata and reticularis?

cortisol
adrenal androgens

10

What does the adrenal medulla secrete in response to sympathetic nerve stimulation?

Adr and to a lesser extent NA

11

What does the adrenal medulla secrete in response to?

Stress preparing for "fight or flight"
Priming the body for intense physical activity

12

What does the adrenal medulla stimulate release of?

Metabolic "fuels"
Glucose from the liver
Fatty acids from adipose tissue

13

What are the actions of Adr in these tissues mediated by?

Elevations in cyclic AMP levels

14

How do Adr and NA maintain blood pressure?

Ionotropic effects on the heart (increases heart rate) and vasoconstrictor (contracts blood vessels)

15

How are people with hypertension treated?

Beta-adrenoceptor antagonists (‘beta blockers’) to reduce HR

16

What does failure of the adrenal medulla cause?

Hypotension

17

What is hypotension?

Low blood pressure

18

What is hypertension

High blood pressure

19

What are examples of tumours of the adrenal medulla?

Pheochromocytoma or neuroblastoma

20

What do tumours of the adrenal medulla cause?

Secretion of catecholamines causing hypertension and must be removed by surgery

21

What are adrenocortical hormones?

Steroid hormones

22

What is adrenocortical hormones structure based on?

Cholestrol

23

What are exampels of adrenal Corticosteroids?

Mineralocorticoids- aldosterone
Glucocotortoids- Cortisol
Sex hormone- androgens

24

What do adrenal Corticosteroids act on?

Intracellular nuclear receptors

25

What leads to the transcription of genes?

Receptor plus hormone unfolds and binds to DNA hormone response elements

26

What does the receptor plus hormone unfold and bind to?

DNA at HRB (Hormones Response Elements)

27

What does the receptor hormone complex do once bound to DNA?

Increases RNA polymerase activity
Increase production of specific mRNAs
Increases protein synthesis

28

What are nuclear (or cytoplasmic) receptors?

Soluble proteins localised within the cytoplasm or the nucleoplasm

29

What does the nuclear receptor have to pass through?

Plasma membrane
Usually by passive diffusion

30

What are the typical ligand?

Lipophilic hormones, with steroid hormones (e.g. testosterone, progesterone and cortisol) and derivatives of vitamin A and D among them

31

What happens when the ligand is binding?

Nuclear receptors pass through the nuclear membrane into the nucleus genes activity

32

What are specific Hormone Responsive Elements (HREs)?

A short sequence of DNA within the promoter of a gene that is able to bind a specific hormone receptor complex and therefore regulate transcription

33

What happens when ligands bind to receptors which unfold?

Bind receptor binds to DNA
RN polymerase activity increases
Specific mRNA is produced within minutes
Protein synthesis- effects in hours to days

34

How does Oestrogen Receptor Agonists activate nuclear receptors?

For hormone replacement therapy in postmenopausal women (conjugated equine oestrogens)

35

What is glucocorticoid receptor agonist for?

For inflammation (hydrocortisone,; dexamethasone)

36

What is mineralocorticoid receptor antagonist for?

For oedema due to liver cirrhosis and for heart failure (spironolactone)

37

What are oestrogen receptor antagonists?

For the prevention and treatment of breast cancer (tamoxifen)

38

What are androgen receptor antagonists?

Treatment of prostate cancer (Bicalutamide/Casodex)

39

What are agonists?

Agonist drugs mimic the effects of neurotransmitters naturally found in the human brain

40

What are antagonists?

In contrast to agonist drugs which bind to the neurotransmitters in the brain, antagonist drugs do the opposite: they block the brain’s neurotransmitters

41

What does aldosterone do?

Regulate salt and water metabolism
Retains Na+ in exchange for K+
Retains water

42

What is the production of aldosterone regulated by?

Renin/Angiotensin system

43

What is the aldosterone antagonist?

Spironolactone- used as a Potassium sparing diuretic

44

What does aldosterone act on?

Distal renal tubules to increase Na+ reabsorption and concomitantly, increased excretion of K+ and H+

45

Where are aldosterone nuclear receptors?

Only occur in the kidneys

46

What is spironolactone?

Competitive antagonist of aldosterone at these receptors

47

What's the effect of interaction of the aldosterone?

Receptor complex with DNA is to increase the number of Na+ channels in the membrane of the renal cell

48

What are the three main actions of glucocorticoids?

Metabolic
Negative feed-back on anterior pituitary and hypothalamus
Anti-inflammatory and immunosuppressive effects

49

What are the metabolic actions of glucocorticoids?

Carbohydrates- decreased uptake of glucose, increased protein breakdown to glucose- hyperglycaemia
Proteins- increased breakdown, reduced synthesis
Fat- increased breakdown, redistribution

50

What is used to combat stress?

Raise plasma glucose levels to provide energy

51

What does the anti-inflammatory and immunosuppressive activity reduce?

Blood vessel dilation and leakage
Production of mediators
Inflammatory/ immune cells activity

52

What is anti-inflammatory and immunosuppressive activity?

Glucocorticoids inhibit Phospholipase A2
This block production of Arachidonic Acid, Prostaglandins and Leukotrienes from cell membrane phospholipid

53

When is suppression of inflammation and immune response?

Asthma
Allergic responses
Autoimmune disease
Inflammatory conditions
Organ transplant
Cancer therapy

54

What are the adverse effects of glucocorticoids?

Suppression of response to infection
Suppression of endogenous glucocorticoid synthesis
Metabolic effects
Osteoporosis
Cushing’s syndrome