Endocrine Histology

Question 1

What is the origin of the posterior pituitary and anterior lobes?

Answer 1

• posterior/neurohypophysis from neuroectoderm

- anterior/adenohypophysis from ectoderm (Rathke’s pouch)

Question 2

What is the pars nervosa and what is it made of?

Answer 2

hypothalamohypohyseal tract; neurosecretory fibers from paraventricular nucleus and supraoptic nucleus from hypothalamus to the posterior pituitary lobe

Question 3

What does the supraoptic nucleus secrete?

Answer 3

ocytocin, which stimulates uterine contraction and myoepithelial cells in mammary glands

Question 4

What does the paraventricular nucleus secrete?

Answer 4

vasopressin aka ADH, which tells the kidney to retain water by increasing aquaporins

Question 5

Inadequate levels of ADH result in…

Answer 5

diabetes insipidus

Question 6

Where are basophils and acidophils found and what do they do?

Answer 6

both found in pars distalis:

• basophils - regulates activity of other endocrine glands
• acidophils - regulate tissue directly

Question 7

What does ACTH do?

Answer 7

stimulates release of glucocorticoids in adrenal cortex

Question 8

Where are the paraventricular and supraoptic nuclei found?

Answer 8

hypothalamus

Question 9

How many tyrosine molecules do thyroxin hormones have?

Answer 9

2 tyrosine; so T3 has 2 tyrosine and 3 iodines and T4 has 2 tyrosine and 4 iodines

Question 10

What is colloid and how do you get T3/T4 from it?

Answer 10

colloid is thyroglobulin; follicular cells endocytose pre-T3/T4 from it and convert it in the lysosome to active T3/4; secrete for body

Question 11

What is the secretion pathway for TRH and TSH?

Answer 11

TRH from hypothalamus to TSH from pituitary, to TH from thryoid gland

Question 12

Describe hypo and hyperthyroidism.

Answer 12

Hypo: mental/physical sluggishness, CT edema
Hyper: autoimmune where antibodies bind to follicular cells which overproduce TH

Question 13

What does calcitonin do and where does it come from?

Answer 13

lowers blood Ca level; secreted by parafollicular cells in the thyroid gland

Question 14

What does PTH do and where does it come from?

Answer 14

raises blood Ca, secreted by principal/chief cells in the parathyroid gland

Question 15

What are the 3 cell types in Pancreas and what do they secrete?

Answer 15

A - glucagon
B - insulin
D - somatostatin (inhibits both Glucagon and insulin)

Question 16

What are the 3 zones of adrenal cortex and what do they secrete?

Answer 16

granulosa - mineralcorticoids (aldosterone)
fasciculata - glucocorticoids (cortisol)
reticularis - mostly gonadocorticoids (weak androgens) and some glucocorticoids

Question 17

Where are chromaffin cells located and what do they secrete?

Answer 17

adrenal medulla

secrete catecholamines

Question 18

What is the general blood supply of the adrenal cortex?

Answer 18

capsular artery gives off 2 branches, one feeds top 2 layers before going to veins, the other branch dives to reticularis before connecting to veins