143 - endocrine

Question 1

what does paracrine and autocrine mean?

Answer 1

they are processes where substances are made by cells and then are released into extracellular space to act locally on surrounding cells. Autocrine acts on itself as well.

Question 2

describe the 3 classes of hormones

Answer 2

1) peptides bind to extracellular membrane bound receptors and signal through the intracellular domain.
2) steroids are originally derived from cholesterol. they bind to cytoplasmic receptors and translocate into nucleus to regulate transcription
3) amino acid derivatives are derived from tyrosine. some bind extracellularly (epinephrine) while others go intracellularly

Question 3

describe glucose homeostasis

Answer 3

alpha cells release glucagon when glucose is low. this causes liver gluconeogenesis. this causes blood glucose to rise and causes insulin release from beta cells.

Question 4

give an example of positive feedback

Answer 4

oxtocin is released during a contraction and that causes further contractions and further release of oxytocin

Question 5

what are the purely endocrine glands?

Answer 5

pituitary, pineal, thyroid, parathyroid and adrenal

Question 6

what are the mechanisms of hormone release?

Answer 6

humoral is in response to changing levels of something in the blood. neural is stimulation by nerves. hormonal is stimulation by other hormones.

Question 7

what does the hypothalamus control?

Answer 7

it controls secretions by thyroid, adrenal cortex and gonads.

Question 8

what are the actions of the pituitary hormones?

Answer 8

TSH stimulates thyroid to produce thyroid hormone.
ACTH stimulates adrenal cortex to produce cortisol.
FSH stimulates follicle growth and ovarian estrogen production.
LH has a role in ovulation.
GH stimulates growth of epiphyseal plates.
PRL stimulates mammory glands in breast to make milk.
MSH stimulates melanocytes.

Question 9

what hormones does thyroid release?

Answer 9

thyroid hormone and calcitonin. calcitonin regulates calcium and phosphorous metabolism.

Question 10

describe graves disease

Answer 10

antibodies mimic TSH and cause high TH

Question 11

what cells are in the parathyroid?

Answer 11

rare chief cells and abundant oxyphil cells. Chief cells produce PTH

Question 12

what does PTH do?

Answer 12

raises blood calcium levels by stimulating osteoclasts, decreasing secretion of calcium by kidneys, and by activating vitamin D

Question 13

what does adrenal cortex secrete? adrenal medulla?

Answer 13

aldosterone cortisol; epinephrine

Question 14

what is addison’s disease?

Answer 14

hyposecretion of adrenal cortex.