Histology of Endocrine Organs

Question 1

What is humoral stimuli? Give an example

Answer 1

Release controlled by monitoring levels of ions and nutrients in blood and body fluids

Ex: release of parathyroid hormone stimulated by low serum calcium levels

Question 2

What is neuronal stimuli? Give an example

Answer 2

Release stimulated by nerve signals

Ex: release of epinephrine from adrenal gland in response to a signal from sympathetic nerve fibers

Question 3

What is hormonal stimuli? Give an example

Answer 3

Release caused by a hormone secreted into bloodstream by another endocrine organ or cell

Ex: release of thyroid hormone stimulated by the release of the hormone, TSH, from the pituitary

Question 4

Describe epithelioid cells. Where are they derived from?

Answer 4

Lack free surface and arranged as cords/follicles and some as isolated individual cells; well vascularized vessels often have fenestrated endothelium; derived from epithelia

Question 5

What are the direct targets of hypothalamic hormones?

Answer 5

Anterior pituitary gland, kidney and uterus, adrenal medulla

Question 6

What are the indirect targets of hypothalamic hormones?

Answer 6

Thyroid gland, adrenal cortex, mammary gland, gonads (testes/ovaries), bone and other organs

Question 7

What are somatotropic cells?

Answer 7

Cells that secrete GH

Question 8

What are thyrotropic cells?

Answer 8

Cells that secrete TSH that regulates thyroid gland secretion

Question 9

What are corticotropic cells?

Answer 9

Secrete ACTH and melanocyte-stimulating hormone (MSH), which stimulates melanocytes to produce melanin

Question 10

What are gonadotropic cells?

Answer 10

Secrete FSH and LH

Question 11

What are mammotropic cells?

Answer 11

Cells that secrete prolactin that stimulates milk production

Question 12

What are the cells found in the pars distalis of the anterior pituitary?

Answer 12

Acidophils, basophils, chromophobes

Question 13

What are the acidophils and basophils?

Answer 13

Acidophils: somatotrophs, mammotrophs

Basophils: corticotrophs, thyrotrophs, gonadotrophs

Question 14

What is the antidiuretic hormone?

Answer 14

Targets the kidney; regulates sodium and water retention

Question 15

What is oxytocin?

Answer 15

Targets uterine smooth muscle and stimulates lactation; induces birth; may be involved in sexual arousal and pair and social bonding

Question 16

What is Grave’s disease?

Answer 16

Abnormal antibodies stimulating TSH receptors causing over-secretion of T3 and T4; symptoms are elevated metabolism, sweating, rapid heart rate, weight loss, eyeballs may protrude; 4-8x more common in women

Question 17

What is hypothyroidism?

Answer 17

Insufficient T3 and T4 production often an autoimmune disease-causing follicle cell death; symptoms are low metabolic rate, weight gain, lethargy, chilliness, edema, mental sluggishness

Question 18

What is goiters?

Answer 18

Thyroid enlargement most commonly due to iodine deficiency; follicle cells keep producing thyroglobulin but cannot iodinate to make TH

Question 19

What cells are found in the parathyroid gland?

Answer 19

Chief (principle) cells and oxyphil cells

Question 20

What is the function of chief (principle) cells in the parathyroid?

Answer 20

Release PTH; secretion occurs when the blood concentration of calcium falls below the normal range of 9.5-10.5 mg/dL; secretion stops when the level of calcium returns to normal

Question 21

What is the mechanism by which PTH regulates calcium?

Answer 21

Calcium blood levels drop below 9.5 mg/dL:

1) Stimulates osteoclasts to resorb bone and release its calcium stores
2) Increase calcium retention by the kidneys
3) Stimulates kidney to convert an inactive form of vitamin D to calcitriol (active vitamin D)
4) Calcitriol increases calcium absorption by the intestines
5) Blood calcium levels increase and inhibits further PTH release

Question 22

Describe epinephrine and norepinephrine chromaffin cells

Answer 22

Epi: smaller with granules less electron dense than norepinephrine cells

Norepi: larger with granule more electron dense

Question 23

What cells are found in the endocrine pancreas?

Answer 23

Alpha cells, beta cells, delta cells, F-cells

Question 24

What is the function of alpha cells in the endocrine pancreas?

Answer 24

Secrete glucagon when blood glucose levels drop; stimulates release of glucose from liver glycogen stores

Question 25

What is the function of beta cells in the endocrine pancreas?

Answer 25

Secrete insulin when blood glucose levels are elevated and promotes glycogen storage in liver and entry into cells

Question 26

What is the function of delta cells in the endocrine pancreas?

Answer 26

Secrete somatostatin slowing the release of insulin and glucagon thereby controlling the rate of nutrient entry into the bloodstream and cells; stimulated by high levels of nutrients in the bloodstream

Question 27

What is the function of F-cells in the endocrine pancreas?

Answer 27

Secrete pancreatic polypeptide that inhibit the release of somatostatin