Suprarenal gland Flashcards
What are the major topics covered in the presentation
Pituitary gland. Thyroid gland. Calcium metabolism disorders. Suprarenal gland. Diabetes mellitus
What are the primary functions of the adrenal glands
Regulation of stress response. Water. Sodium & potassium balance. Blood pressure control
What are the two components of the adrenal gland
Adrenal cortex. Adrenal medulla
What hormones do the adrenal cortex layers produce
Zona Glomerulosa → Mineralocorticoids (Aldosterone). Zona Fasciculata → Glucocorticoids (Cortisol). Zona Reticularis → Androgens (DHEA)
In what forms does cortisol circulate in plasma
Free cortisol. Protein-bound cortisol. Cortisol metabolites
What is the major organ responsible for steroid inactivation
Liver
What stimulates the release of ACTH from the anterior pituitary
Corticotropin-releasing hormone (CRH)
What factors control ACTH release
CRH. Free cortisol levels. Stress. Sleep-wake cycle
What is the half-life of ACTH in circulation
Less than 10 minutes
What is the function of Renin
It converts angiotensinogen (from the liver) into angiotensin I
How is Angiotensin I converted into Angiotensin II
By Angiotensin-Converting Enzyme (ACE) in the pulmonary endothelium
What is the primary function of Angiotensin II
It is a potent vasoconstrictor and stimulates aldosterone production
What are the three main regulators of renin release
Juxtaglomerular cells (sense renal perfusion pressure). Macula densa cells (monitor sodium levels). Sympathetic nervous system (β-receptors)
What are the three major syndromes of adrenal cortex hyperfunction
Cushing Syndrome. Hyperaldosteronism. Virilizing Syndromes
What is the most common cause of Cushing Syndrome
Exogenous glucocorticoid administration
What are the three endogenous causes of Cushing Syndrome
Primary hypothalamic-pituitary disease (Cushing Disease). Adrenocortical hyperplasia or neoplasia. Ectopic ACTH secretion (e.g. small cell lung carcinoma)
What is the best screening test for Cushing Syndrome
24-hour urine free cortisol
What test detects loss of diurnal variation in cortisol secretion
Midnight salivary cortisol test
What is the high-dose dexamethasone suppression test used for
To differentiate between pituitary and ectopic ACTH production
What is the best treatment for Cushing Syndrome
Surgical removal of the lesion (transsphenoidal surgery for pituitary adenoma)
What treatment options exist for inoperable cases
Radiation therapy. Medical therapy (e.g. ketoconazole). Bilateral adrenalectomy
What are the major symptoms of hyperaldosteronism
Hypertension. Hypokalemia
What is the most common cause of primary hyperaldosteronism
Aldosterone-secreting adrenal adenoma (Conn’s Syndrome)
How is primary hyperaldosteronism diagnosed
Aldosterone-to-renin ratio (>20)
