3. The adrenal glands Flashcards
Location of adrenal gland?
Lie retroperitoneally on the upper pole of the kidneys
Embryological origin of adrenal cortex and medulla?
Adrenal Cortex: arises from intermediate mesoderm
Adrenal Medulla:
Neural crest cells
Chromaffin cells
Modified sympathetic ganglion cells
Layers of the adrenal gland?
Capsule Zona glomerulosa Zona Fasciculata Zona reticularis Medulla
What hormones are produced by the Zona glomerulosa?
Control and use?
Mineralocorticoids – e.g. aldosterone
Controlled by renin – angiotensin
Use:
Electrolyte and fluid homeostasis
What hormones are produced by the Zona Fasciculata?
Control and use?
Glucocorticoids – e.g. cortisol
Secretion controlled by ACTH
Use:
Carbohydrate, lipid and protein Metabolism
What hormones are produced by the Zona reticularis?
Sex steroids – androgens
What hormones are produced by the medulla?
Catecolamines e.g. epinephrine
Adrenal Cortex Produces ______ hormones
Adrenal Cortex Produces STEROID hormones
Adrenal Cortex Blood supply?
• Supplied by the superior middle and inferior adrenal arteries; anastomose under the capsule
Cortex and medulla difference in supply?
• Cortex receives short cortical arteries run in parallel with the cords of cells to the medulla
• Medulla receives
-blood draining from the cortex (containing
adreno-corticosteroids which influence the production of adrenaline by the medullary cells)
- Fresh arterial blood in long cortical arteries
Adrenal gland involved in …
stress response both LONG TERM and SHORT TERM
What makes up the short term stress response by the adrenal gland due to CATECHOLAMINE RELEASE?
Increased HR
Increased bp
Liver converts glycogen ot glucose and releases glucose to blood
Brochodilatation
Changes blood distribution causing decreased GI and increased urinary
Increase BMR
What makes up the long term stress response by the adrenal gland due to MINERALOCORTICOID RELEASE?
e.g. aldosterone
- Retention of Na and water of kidneys
2. Increased BP
What makes up the long term stress response by the adrenal gland due to GLUCOCORTICOID RELEASE?
e.g. cortisol
- Proteins and fats converted to glucose or broken down for energy
- Increased blood glucose
- Immune system suppression
Need for ACTH and adrenals
Maintains zona glomerulosa hence also mineralocorticoid levels
3 cells where actions of cortisol are located?
Muscle
Liver ** mainly for enzyme synthesis involved in gluconeogenesis.
Fat
Action of cortisol at muscle cell
Reduces uptake of AA and glucose, which is normally stimulated by insulin
Slows protein synthesis and upregulates proteolysis.
Leads to AA release which contributes to gluconeogenesis at liver cell
Action of cortisol at liver cell
Upregulates gluconeogenesis indirectly via enzyme to cause increase in [glucose]