Adrenal Gland Flashcards
Where are the adrenal glands located?
located above kidneys
What is the structure of the adrenal glands?
- paired glands
- outer cortex surrounds inner medulla
What does the adrenal medulla do?
synthesis & secretion of catecholamines
- adrenaline, noradrenaline, dopamine
What are the 3 layers of the adrenal cortex?
- zona glomerulosa
- zona fasciculata
- zona retiscularis
(steroid hormones)
What are the steroid hormones (zona…) made from?
cholesterol
What does zona glomerulosa promote?
- K+ excretion
- Na+ reabsorption
What does zona glomerulosa stimulate?
Na+/K+ ATPase activity
What is zona glomerulosa synthesised and secreted in response to?
- high blood K+
- low blood pressure
What does zona fasciculata secrete in response to?
stress (inc exercise)
What are the actions of zona fasciculata?
- stress hormone
- catabolic hormone
- anti-inflammatory
What does zona fasciculata stimulate?
stimulates glycogenolysis, gluconeogenesis
What does zona fasciculata inhibit?
inhibits activities of phagocytic cells, mast cells & white blood cells
What are the abnormalities of glucocorticoid secretion?
- Addison’s disease
- Cushing’s syndrome
What is Addison’s disease?
Glucocorticoid deficiency
What is Addison’s disease caused by?
- abnormal formation of adrenal gland
- impaired steroid biosynthesis (unable to metabolise steroid)
- destruction of adrenal gland
- rapid withdrawal of glucocorticoid treatment
What are the symptons of Addison’s disease?
- abnormal skin pigmentation
- fatigue
- weight loss
- low blood pressure
- hypoglycaemia
What is Cushing’s syndrome?
glucocorticoid excess
What is Cushing’s syndrome caused by?
- adrenal tumour: produce excess glucocorticoids
- pituitary tumour: produce excess ACTH
- excess clinical use of glucocorticoids
What are the symptoms of Cushing’s syndrome?
- high blood pressure
- type 2 diabetes
- mobilisation & redistribution of fat
- muscle weakness, loss of muscle protein
- osteoporosis (weak, brittle bones)
What type of steriod hormone does zona reticularis produce?
sex steroid hormones
- esp androgen
What does zona reticularis do?
- produce sex steroids at puberty
- responsible for early secondary sexual characteristics
What are the abnormalties in androgen secretion?
congenital adrenal hyperplasia
