Hypothalamic-Adrenal-Pituitary, Thyroid Hormones

Question 1

what are the 6 main hormones made in the anterior pituitary (adenohypophysis)?

Answer 1

TSH, ACTH, FSH, LH, GH, and prolactin

Question 2

what does TSH target and where made?

Answer 2

Thyroid stimulating hormone; made in anterior pituitary, targets the thyroid

Question 3

what promotes the production of TSH?

Answer 3

thyrotropin releasing hormone produced in hypothalamus

Question 4

what two main hormones are produced in the posterior pituitary (neurohypophysis)?

Answer 4

oxytocin, and ADH (antidiuretic hormone aka vasopressin)

Question 5

what controls secretion of hormones from the pituitary?

Answer 5

releasing or inhibiting hormones made in the hypothalamus

Question 6

what hormones are produced in the hypothalamus that affect the pituitary?

Answer 6

CRH - corticotropin releasing hormone; TRH- thyrotropin releasing hormone; GH-releasing hormone; somatostatin (GH inhibitor); Gn-RH (gonadotropin releasing) and PRL-inhibiting factor which is actually dopamine

Question 7

what is the function of LH?

Answer 7

luteinizing hormone in females: induces ovulation and ovarian secretion of estrogen and progesterone males: stims testes to produce androgens

Question 8

function of FSH

Answer 8

females: promotes egg development and secretion of estrogen males: supports sperm production, stims secretion of testosterone

Question 9

function of TSH

Answer 9

stims thyroid to produce T3/T4

Question 10

what will be the relative concentrations of TSH, T3 and T4 in primary vs secondary hypothyroidism?

Answer 10

primary: increased TSH, decreased T3 and 4 secondary: all 3 decreased

Question 11

what is primary vs secondary hypothyroidism?

Answer 11

primary means the issue is with the thyroid gland itself which could be due to loss of function, infiltrative disease or due to defects in hormone synthesis secondary means the issue stems from either the pituitary (TSH deficiency) or hypothalamus (TRH def)

Question 12

what is the most frequent cause of primary hypothyroidism in developed countries vs worldwide?

Answer 12

In developed nations it is Hashimoto’s (nongoitrous), often associated with antithyroid antibodies Worldwide it is iodine deficiency (causes goiter)

Question 13

what are the relative levels of TSH, T3 and 4 in hypERthyroidism?

Answer 13

increased T3 and T4, decreased TSH

Question 14

what is the most common cause of hyperthyroidism in the U.S. (give name and simple etiology); what can be other causes?

Answer 14

Grave’s disease: development of circulating IgG against TSH receptors on the thyroid, causing overproduction of T3 and T4 due to the negative feedback Cam also be due to toxic multinodular goiter (Plummer’s) or adenoma on thryoid

Question 15

what is another term used in place of hyperthyroidism and it smeaning

Answer 15

thyrotoxicosis, defines the hypermetabolic state induced by increased amounts of circulating T3 &4

Question 16

what is the function of ACTH

Answer 16

adrenocorticotropic hormone, made in the ant pit, stimulates the adrenal cortex to secrete glucocorticoids, esp cortisol

Question 17

In Addison’s disease, what will be circulating in increased amounts and why?

Answer 17

increased circulating ACTH bc of a lack of cortisol to act as the negative feedback stimulus

Question 18

among the glycoprotein hormones of the ant pit, how are the hormones structured and what is distinctive between them?

Answer 18

they are of two peptide chains with carbohydrate moieties. The alpha subunits are similar, but the B subunits distinguish them from each other

Question 19

what is another term for TSH and what does it promote the thyroid gland to do?

Answer 19

thyrotropin; promotes growth and uptake of iodine and stims secretion of the thyroid hormones

Question 20

what are alternative terms for ADH, where is it formed and stored?

Answer 20

arginine vasopressin or just vasopressin; formed in neurons of the hypothalamus and stored in the posterior pituitary (neurohypophysis)

Question 21

what does ADH/vasopressin do to: capillaries/arterioles intestinal muscles kidney tubules

Answer 21

1. stims contraction of capillary and arteriole muscle to raise blood pressure 2. promotes contraction of GI muscles to cause peristalsis 3. causes reabsorption of free water to concentrate urine and dilute blood serum

Question 22

what regulates ADH secretion, PRIMARILY? secondarily? other?

Answer 22

plasma osmolarity; baroreceptors that respond to changes in blood volume; many other stimuli can cause ADH release: pain, stress, sleep, exercise, chemi agents like angiotensin II, catecholamines

Question 23

where is oxytocin made and stored?

Answer 23

hypothalamus, stored in post pit

Question 24

on what part of the kidney does ADH act ?

Answer 24

the distal convoluted tubules to increase water reabsorption

Question 25

what disorder is associated with ADH excess and lack?

Answer 25

excess: SIADH lack of: diabetes insipidus

Question 26

what is the effect of diabetes insipidus on electrolyte levels? SIADH?

Answer 26

It concentrates them bc too much fluid is lost, so hypernatremia; too much fluid retained without electrolyes, so in SIADH, hyponatremia

Question 27

where are human steroid hormones synthesized primarily, and from what precursor substance?

Answer 27

in the adrenals and gonads; from cholesterol acquired from circulating LDL or it can also be synthesized intracellularly

Question 28

where are steroids metabolized and how excreted?

Answer 28

in the liver, and to a lesser extent in kidney and GI tract; they are conjugated with glucuronic or sulfuric acids to be excretes as water-soluble metabolites in the urine

Question 29

what are three major categories of steroids synthesized in adrenals?

Answer 29

glucocorticoids (think cortisol), mineralocorticoids (think aldosterone) and adrenal androgens plus progesterone and estrogen (obv also made in gonads)

Question 30

major actions of cortisol the primary glucocorticoid include:

Answer 30

affects all macronutrient metabolism including raising blood glucose and release of FFAs OR lipogenesis have antiinflammatory properties, thus are used therapeutically

Question 31

Name and primary function of the most potent mineralcorticoid

Answer 31

aldosterone; regulates salt homeostasis and ECF

Question 32

where in the adrenal are the glucocorticoids and mineralocorticoids synthesized?

Answer 32

cortex, specifically the zona fasciculata and glomerulosa respectively

Question 33

what are the most important adrenal androgens

Answer 33

DHEA/ dehydroepiandrosterone and androstenedione

Question 34

in a normal individual how would cortisol levels be between a morning and afternoon sample?

Answer 34

levels are diurnal, higher at 8 a.m. and lower at 4 p.m.

Question 35

In decreased cortisol production such as in Addison’s disease, how would blood glucose be affected?

Answer 35

lower- more likely hypoglycemic

Question 36

what regulates secretion of adrenal glucocorticoids and androgens? what regulates this regulator in turn?

Answer 36

ACTH from the posterior pituitary, which is in turn regulated by CRH from the hypothalamus

Question 37

what is the primary control mechanism for secretion of aldosterone? what does aldosterone do?

Answer 37

the renin-angiotensin system; aldosterone increases Na+ reabsorption (thus water) and potassium excretion

Question 38

In Hyperaldosteronism, what is the effect on sodium and potassium?

Answer 38

increased serum Na+ (hypernatremia) and reduced K+, hypokalemia

Question 39

what part of the nephron does aldosterone exert its effect upon?

Answer 39

the distal tubule

Question 40

what 3 main hormones are made in the adrenal cortex vs adrenal medulla?

Answer 40

cortex: glucocorticoids (cortisol), mineralocorticoids (aldosterone), and androgens (testosterone)
medulla: the catecholamines which includes epi, norepi, and dopamine

Question 41

what is the overarching function of the catecholamines and what are the 3 main ones metabolized into?

Answer 41

mobilization of energy stores, esp norepinephrine, epinephrine: increase BP, blood glucose (fight or flight response); dopamine is a neurotransmitter and has key roles in locomotion, learning, reward center of brain.

norepinephrine: becomes normetanephrine—>vanillylmandelic acid (VMA)

epinephrine is metabolized to metanephrine—>VMA

dopamine—> homovanillylmandelic (HVA)

Question 42

what is a pheochromocytoma? sign and sx? lab values?

Answer 42

a tumor of the adrenal gland chromaffin cells that produces catecholamines

s&sx: HTN, headache, palpitations, excess sweating, nausea, anxiety, weakness

lab values: incrsd plasma catecholamines; increased urinary metanephrines and VMA

Question 43

what is a neuroblastoma, plus lab analytes to aid diagnosis

Answer 43

tumors almost all occuring in children deriving from neural crest cells, ~60% extraadrenal and ~40% adrenal. most found in abdominal areas. Metabolites HVA (of dopamine) and VMA (of norep) in urine is most used lab testing

Question 44

what pituitary hormones rise at ovulation? other?

Answer 44

FSH and LH; also estrogen/estradiol

Question 45

when does progesterone rise?

Answer 45

about 8 days after the LH peak, so also after ovulation

Question 46

what is the principle estrogen? what happens to it at full term pregnancy?

Answer 46

estradiol; should increase or plateau at full term

Question 47

what is the function of progesterone?

Answer 47

to prepare the uterus for pregnancy by maintaining the uterine lining, inhibiting contractions, and preparing breasts for lactation

Question 48

When is progesterone higher than normal, from a lifetime perspective?

Answer 48

durig peri-menopause

Question 49

what is the function of HCG?

Answer 49

it maintains progesterone in earrly pregnancy