ENDO Week 9 Flashcards by Diva Uppal

where is the adrenal gland located

located on the superior pole of each kidney

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what are the 2 regions of the adrenal gland

adrenal cortex (outer region)
adrenal medulla (inner region)

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what is the adrenal medulla composed of and secrete?

 Composed of modified sympathetic ganglion cells
 Secretes catecholamines (epinephrine and norepinephrine)

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what does the adrenal cortex secrete

 Secretes steroid hormones (corticosteroids)
 Primarily secretes C21 and C19 steroids

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what are the three cortical zones of the adrenal cortex

zona glomerulosa
zona fasciculata
zona reticularis

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what does the zone glomerulosa secrete and why

 Secretes aldosterone (mineralocorticoid)
 Only zone which produces aldosterone because it contains aldosterone synthase which converts corticosterone to aldosterone

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what does the zone fasciculata secrete

mainly glucocorticoids

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what does the zona reticularis secrete

mainly adrenal androgens

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what are adrenal cortex steroid hormones formed from

from cholesterol to pregnenolone (first step of steroid biosynthesis)**

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what are the three types of steroid hormones and examples of each

o Mineralocorticoids: Aldosterone

o Glucocorticoids: Cortisol

o Androgens: DHEA, Androstenedione

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what glucocorticoid hormone is secreted by the zone fascsiculata of the adrenal cortex?

cortisol

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what kind of hormone class is cortisol and where does it bind on the cell

steroid hormone
lipophilic, binds to intracellular membrane

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how does cortisol travel in blood

bound: to transcortin, corticosteroid-binding globulin (CBG)

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what is the effect of cortisol on BG

increases BG
- increases gluconeogenesis in liver (increase glucose from liver)
- decreased glucose uptake by muscle and fat

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what is the action of cortisol on protein metabolism

proteolysis, protein catabolism, increase amino acid transport in liver (used for gluconeogenesis, increase BG)

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what is the action of cortisol on fat metabolism

lipolysis, increases FFA

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what is the action of cortisol on BP, inflammation and immunity

-increases BP (sodium reabsorption and potassium excretion)

-anti-inflammatory effect (increase anti-inflammatory cytokine production, decrease pro inflammatory cytokines**)

-reduced immunity (increase RBC and platelets)

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describe the regulation of cortisol

Hypothalamus-pituitary-adrenal cortex axis
corticotropes in pituitary, increase synthesis of cortisol in adrenal cortex
CRH-ACTH-cortisol, neg feedback mechanism of cortisol on acth and crh**

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what mineralocorticoid is secreted by the zona glomerulosa of the adrenal cortex

aldosterone, most potent mineralocorticoid

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what kind of hormone is aldosterone and how does it travel in blood

steroid hormone, travels bound to albumin and corticosteroid binding protein (CBG)

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what is the principle action

electrolyte regulation
- increases sodium potassium pump activity
- increases sodium reabsorption, decreases sodium excretion
- increases potassium excretion

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what is the mechanism of action of aldosterone’s principle action

Aldosterone combines with cytoplasmic receptor in principle cell of collecting duct (kidney)
Hormone receptor complex initiates transcription in the nucleus
Translation and protein synthesis makes new protein channels and pumps
Aldosterone-induced proteins modulate existing channels and pumps
Result is increased sodium reabsorption and increased potassium

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what is excess aldosterone secretion called and what can it cause

hyperaldosteronism –> hypokalemia

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what is the effect of aldosterone in the intestine

Study These Flashcards

increases sodium absorption

what is the RAAS system and how does it regulate aldosterone

renin-angiotensin-aldosterone system ** formation of angiotensin II, stimulates aldosterone secretion

how does sodium and potassium regulate aldosterone

increased potassium (hyperkalemia) stimulates aldosterone because it causes potassium excretion increased sodium inhibits aldosterone

what are other factors which regulate aldosterone

ACTH (not the primary stimulation factor of aldosterone) - During stress --> CRH --> ACTH --> increase aldosterone ANP (atrial natriuretic peptide) - blocks renin, inhibits aldosterone secretion

what androgen hormones are secreted by the zone reticularis

androstenedione and DHEA

what kind of hormones are androstenedione and DHEA and how do they travel in blood

steroid hormone travel bound with albumin and globulin

what stimulates the secretion of adrenal androgens

ACTH

what is hypersecretion of corticosteroids called

adrenocortical hyperfunction

what are some syndromes caused by adrenocorticol hyper function and what specific corticosteroid does it relate to

1. Cushing’s syndrome: excess glucocorticoids, chronic hypercortisolism 2. Conns syndrome: excess mineralocorticoids, primary hyperaldosteronism 3. Adrenogenital syndrome: excess adrenal sex steroids, adrenal virilism

what is Cushing's syndrome caused by

hypercortisolism (excess cortisol secretion)

what are the 4 types of Cushing's syndrome

1. Pituitary Cushing’s syndrome 2. Adrenal Cushing’s syndrome 3. Ectopic Cushing’s syndrome 4. Iatrogenic Cushing’s syndrome

what is pituitary Cushing's syndrome and its effect on ACTH level

- secondary disorder (pituitary) - AKA Cushing’s disease, most common - Excess secretion of ACTH from pituitary

what is adrenal Cushing's syndrome and its effect on ACTH level

- primary (disease of adrenal glands) - Causes cortical hyperplasia - Low ACTH levels

what is ectopic Cushing's syndrome and its effect on ACTH levels

- Nonendocrine tumours are secreting ACTH instead of anterior pituitary - Lung carcinoma or pancreatic tumours secreting ACTH - Increased plasma ACTH

what is iatrogenic Cushing's syndrome

Prolonged therapeutic administration of high doses of glucocorticoids or ACTH

what are some signs and symptoms of Cushing's syndrome

* Weight gain, central/truncal obesity * Fat over shoulders – Buffalo hump * Moon face – rounded, edematous face * Wasting of muscles * Hypertension

what is Addisons disease

- primary adrenocorticol insufficiency - decreased cortisol levels (hypocorticolism) - decreased aldosterone - increased ACTH - autoimmune: destruction of the gland

what are some clinical manifestations of Addisons Disease?

 Hyperpigmentation, caused by increased ACTH  Mineralocorticoid (aldosterone) deficiency causes hyponatremia and hyperkalemia

how does Addisons disease cause acidosis

decreased aldosterone --> decreases H+ excretion --> acidosis

how does congenital adrenal hyperplasia affect adrenal cortex hormones

not enough production of cortisol and/or aldosterone, and too much of androgens

how does congenital adrenal hyperplasia affect ACTH and what does this cause

increases ACTH because cortisol is low, this drives adrenal androgen production

what is congenital Adrenal hyperplasia caused by

Deficiency of 21-hydroxylase ***

what is the effect of primary and secondary adrenocorticol insufficiency

primary: low cortisol (issue with adrenal cortex) causes high ACTH secondary: low ACTH (issue with pituitary) causes low cortisol

what does hyper secretion of adrenal androgens cause in females

hirsutism (male pattern hair growth)

what is 21-hydroxylase deficiency

accounts for 95% of genetic abnormalities in adrenal steroid hormone synthesis

what is another name for the adrenal medulla

modified sympathetic ganglion

what cells make up the adrenal medulla

pheochromocytes/chromaffin cells - large cells that are innervated by sympathetic preganglionic fibers axons less secretory cells

what is the function of the adrenal medulla cells

release catecholamines (norepinephrine, epinephrine, dopamine) to the bloodstream

what are catecholamines synthesized from

tyrosine

what is PNMT (phenylethanolamine-N-methyltransferase) and what does it require to function

* Enzyme that catalyzes norepinephrine --> epinephrine (last step of biosynthesis) * Requires cortisol from adrenal cortex***

what happens to catecholamines after they are synthesized

o Preformed stored in vesicles, chemical signal triggers exocytosis

what kind of hormones are catecholamines, how do they travel in blood and where can they bind

amine hormone travels in free form lipophobic, binds to membrane receptor, GPCR

what is the effect of catecholamines on skeletal muscle, adipose tissue and liver

o Skeletal muscle: glycogenolysis o Adipose: lipolysis o Liver: glycogenolysis, gluconeogenesis

what are some effects of catecholamines

Fight or flight reaction  Increases BG  Increase energy  Skeletal muscle activity increases  Increases cardiac output, increase HR  Bronchodilation

what is pheochromocytoma and what does it cause

- Adenoma of adrenal medulla - Causes excess production of catecholamines (Increase HR, RR, vasoconstriction of periphery: increase BP)

ENDO Week 9 Flashcards

(58 cards)