Endocrine Review

Question 1

What controls the “master gland”

Answer 1

hypothalamus

Question 2

Describe FSH

Answer 2

Stimulated by GnRH
stimulates the follicles of the ovaries to produce estrogen
stimulates Sertoli cells for spermatogenesis

Question 3

Describe LH

Answer 3

stimulated by GnRH
Stimulates ovulation and the production of progesterone
stimulates the interstitial cells of Leydig in the testis to produce testosterone

Question 4

Describe ACTH

Answer 4

stimulated by CRH (corticotropin releasing hormone)
governs synthesis of cortisol and pregenolone in the adrenal cortex
increased ACTH is seen in Cushings syndrome

Question 5

Describe TSH

Answer 5

stimulated by thyroid stimulating hormone
stimulates thyroid to produce thyroxine
increased thyroxin = hyperthyroidism
Decreaced thyroxin = hypothyroidism

Question 6

Describe GH

Answer 6

stimulated by GHRH
stimulates bone and tissue growth through somatomedins A-C
increased GH results in gigantism or acromegaly
decreased GH is seen in pituitary dwarfism

Question 7

Describe Prolactin

Answer 7

affected by prolactin inhibiting factor (dopamine) and TRH
promotes breast development and milk production
does NOT cause milk ejection

Question 8

Describe the two hormones stored in the neurohypophysis

Answer 8

Oxytocin:
Secreted mainly by the paraventricular nucleus in the hypothalamus
Stimulates contraction of uterine muscle milke ejection
Also plays a role in maternal bonding through release from breast stimulation
Controlled by positive feedback loop

ADH:
secreted mainly by supraoptic nucleus
acts on collecting ducts in the kidney
released in response to water deprivation
prevents diuresis (water excretion)
Lack of ADH results in diabetes insipidus (polyuria and polydypsia)

Question 9

What does the pars intermedia secrete

Answer 9

Melanin Stimulating hormone
Stimulates melanin production from melanocytes
produced from Pro-OpioMelanCortin (POMC) from which MSH and ACTH are formed

Question 10

Describe the thryoid gland

Answer 10

TSH causes iodine to combine with tyrosine.

T3 increases metabolism and is 4x more active than T4

The parafollicular cells of they throid gland secrete calcitonin

Question 11

Describe hypothyroidsim and hyperthyroidism

Answer 11

Hyper:
Graves disease
results in exophthalmos, weight loss, and tremors

Hypo:
results in cretinism in chidlren and myxedema in adults with weight gain, coarse hair and decreased metabolism

Question 12

Describe calcitonin

Answer 12

takes Ca from the blood and puts it back into bone
this has the opposite affect of PTH
plays a minor role in Ca metabolism

Question 13

Describe PTH

Answer 13

Secreted by Chief cells
Takes Ca from bone and puts it into blood
Increases Ca reabsorption in the kidney by acting on cells in the DCT
Increases Ca absorption in the gut
Hyporcalcemia due to hypoparathyroidism excites the nervous system and results in tetany and muscle spasm
Hypercalcemia due to hyperparathyroidism results in muscle fatigue

Question 14

Describe the adrenal cortex

Answer 14

Superficial to deep
Zona glomerulosa - aldosterone (salty)
Zona fasciculata - cortisol (sweet)
Zona reticularis - pregnenolone (sex)

Question 15

Describe aldosterone

Answer 15

Mineralcorticoid (salt)
Acts on kidneys to regulate Na reabsorption from the DCT
Causes water retention and increase in BP
Under the influence of renin which is secreted by juxtaglomular cells
Excess aldosterone is seen in Conn’s syndrome - high Na, hypertension, and low K

Question 16

Describe cortisol

Answer 16

glucocorticoid (sweet) 
Increases lipogensis 
increases glycogensis
increases gluconeogenesis 
Maintains BP 
Decreased bone formation 
suppresses inflammation

Question 17

Describe addison’s disease

Answer 17

destruction of the adrenal cortex

causes weight loss, low BP, and bronzing of skin

Question 18

Describe the adrenal medulla

Answer 18

Secretes epinephrine (80) produced from norepinephrine and norepinephrine (20) produced from tyrosine

Responsible for fight or flight

Question 19

Where are the endocrine cells found in the pancrease

Answer 19

islets of Langerhans

Question 20

Describe Insuline

Answer 20

Secreted by beta type of islet cells
Moves glucose from the blood into the cells
promotes synthesis of fat, glycogen, and protein cellular uptake of K
Inhibits gluconeogenesis, lipolysis, and protein degradation

A decrease in insulin production results in diabetes mellitus causing polyuria, polydypsia, polyphagia, and pruitus

Question 21

Describe the different GLUTs

Answer 21

GLUT 1 - erythrocytes and brain
GLUT 2 - liver and beta islet cells
GLUT 3 - neurons
GLUT 4 - skeletal muscle and adipose tissue

Question 22

Describe glucagon

Answer 22

is secreted by alpha cells
causes liver to convert glycogen to glucose (glycogenolysis)

released when blood levels are low

Question 23

Describe somatostatin

Answer 23

secreted by delta cells
it is also secreted by D cells in the stomach and by the hypothatlamus
AKA as GH inhibitory hormone as it inhibits the following:
Renin
Insulin
GH
Gastrin
Glucagon