Adrenocortical function and dysfunction Flashcards Preview

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Flashcards in Adrenocortical function and dysfunction Deck (30)
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1

Briefly describe the anatomy/histology of the adrenal gland?

Inner medulla: modified sympathetic ganglion

Outer cortex: true endocrine gland 

2 endocrine glands of different embryological origin that fused during development 

2

List the hormones secreted from the adrneal gland, including the location from which they are secreted?

MEDULLA

Catecholamines

CORTEX

Zona reticularis: sex hormones

Zona fasiculata: glucocorticoids

Zona glomerulosa: mineralocorticoids

3

Where are glucocorticoids and sex hormones released from?

Sex hormones primarily from reticularis, also a little from fasiculata

Glucocorticoids primarily from fasiculata, also a little from reticularis

4

Describe the pathway for steroid hormone synthesis?

What determines the production of steroid hormones by cells?

Cells produce different hormones because they have different enzymes present 

5

Describe the HPA pathway for control of cortisol secretion?

6

Describe the functions of CRH and ACTH, other than that in the HPA axis?

Stress related functions in immune and nervous systems

CRH: effects on inflammation and immune response, inhibition of appetite, signlas onset of laboor, linked to mood disorders

7

What is POMC?

Pro-opiomelanocortin

Large protien that yields several bioactive peptides by proteolysis

 

8

List some of the bioactive peptides yielded from POMC?

Anterior pituitary: ACTH, b-endorphins

Outside pituitary: a-MSH

9

Describe the effect of a-MSH?

Melanocyte-stimulating hormone > decrease food intake and increase skin melanin

10

How does cortisol protect against hypoglycaemia?

Stimulates catabolism of energy stores

11

How does the action of cortisol relate to glucagon and catecholamines?

Cortisol is permissive for the actions of glucagon and catecholamines

12

Describe the actions of cortisol?

Promotes gluconeogenesis in liver

Causes breakdown of skeletal muscle proteins

Enhances lipolysis

Immune suppression

Causes negative calcium balance (decreased absorption, increased excretion, bone breakdown)

Adaptation to stress

Influences brain function

 

 

13

Describe the effect of cortisol on calcium in the body?

Causes negative calcium balance, by decreasing absorption, increasing excretion and bone breakdown

14

Describe the effects of long term cortisol use as a therpaeutic drug?

Inhibition of ACTH secretion (negative feedback)

Atrophy of cortisol secreting cells 

So, must taper doses gradually 

15

How is cortisol transported in the circulation?

Corticosteroid binding globulin 

16

What is the half-life of cortisol?

60-90 minutes 

17

Describe the factors affecting cortisol release?

Circadian rhythm of tonic secretion 

Stress enhances release 

18

Where is the target receptor for cortisol located?

Most tissues

Intracellular (lipophilic)

19

Which disorders are associated with hypersecretion from the adrenal cortex?

Hyperaldosteronism

Cushing's syndrome

Adrenogential syndrome 

20

What causes adrenogenital syndrome?

Lack enzyme in cortisol steroidogenic pathway > pushes away from cortisol production and towards sex steroid production 

21

What are the effects of adrenogenital syndrome?

Inappropriate masculinisation in all but adult males 

22

How is adrenogenital syndrome treated?

Treat with glucocorticoids > repairs glucocorticoid deficit and inhibits ACTH > reduced steroid secretion 

23

Which disorders are associated with hyposecretion from the adrenal cortex?

Addison's disease

Adrenal steroid enzyme defects

Cortisol deficiency

24

Describe the hormones associated with the adrenal medulla?

Chromaffin cells secrete neurohormones 

Catecholamines (adrnealine, NA, dopamine)

25

Why is adrenaline only produced in the adrenal medulla?

Enzyme for conversion to adrenaline from NA (PNMT) only present in adrenal medulla

26

Describe the adrenomedullary hormone actions?

Fight or flight: increase cardiac rate, contractility, TPR and BP

Metabolic: increase glucose and FFA, increase BMR

Central: increase arousal and alertness

Stess responses 

27

Which disorders are associated with hyposecretion from the adrenal medulla?

None recognised

28

Which disorders are associated with hypersecretion from the adrenal medulla?

Pheochromocytomas

29

Describe the two types of stress and their responses?

Acute: fight-or-flight reaction

Chronic: elevates cortisol levels 

30

Briefly describe the physiology of a stress response?