intro to endo 3 W6

Question 1

synergism?

Answer 1

different hormones have same effect on the body - eg blood glucose raised by glucagon, cortisol, epinephrine.
when all 3 are secreted, effect isn’t additive, but synergistic (greater than additive)

Question 2

permissiveness?

Answer 2

one hormone cannot fully exert its effects unless a second hormone is present

Question 3

example of permissiveness - thyroid hormone and reproductive hormone?

Answer 3

just thyroid hormone = no sexual development
just reproductive hormones = so sexual development
thyroid and reproductive hormones = normal sexual development

thyroid hormone has permissive effect on sexual maturation (has to be present for it to occur)

Question 4

antagonism?

Answer 4

action of one hormone opposes effect of another hormone

Question 5

examples of antagonism?

Answer 5

glucagon and insulin
PTH and calcitonin

Question 6

types of antagonistic actions?

Answer 6

compete for same receptor
act through different metabolic pathways
decrease number of receptors for opposing hormone

Question 7

example of antagonistic hormones acting through different metabolic pathways

Answer 7

glucagon and insulin

Question 8

example of antagonistic hormones where they decease the number of receptors for opposing hormone?

Answer 8

growth hormone and insulin

Question 9

3 types of endocrine pathologies?

Answer 9

hormone excess
hormone deficiency
abnormal responsiveness of target tissue to hormone

Question 10

what are most cases of hormone excess due to and how does this occur

Answer 10

hypersecretion, due to:
-benign tumours
-cancerous tumours
-nonendocrine tumours
-iatrogenic

Question 11

problems with exogenous hormone medication?

Answer 11

causes atrophy of gland due to negative feedback
cells shrink and lose their ability to produce hormones
means patients may be unable to regain normal function once treatment is stopped

Question 12

most common cause of hyposecretion?

Answer 12

atrophy of the gland

Question 13

what occurs during hyposecretion?

Answer 13

negative feedback pathways are affected
trophic hormone levels increase in an attempt to raise levels of hyposecreted hormone

Question 14

downregulation?

Answer 14

abnormally high hormone secretions may cause target cells to downregulate (decrease no of receptors in an effort to reduce response)

Question 15

testicular feminization syndrome?

Answer 15

androgen receptors are non functional (genetic mutation). androgens produced by developing fetus unable to influence genitalia development, child appears female but lacks uterus and ovaries

Question 16

pseudohypoparathyroidism?

Answer 16

patient displays signs of low parathyroid hormone, even through blood hormone levels are completely fine. inherited defect in G protein, no linking of receptor to adenylyl cyclase

Question 17

3 possible causes of excess cortisol secretion?

Answer 17

hypothalamic problem (high CRH, ACTH, cortisol)
pituitary problem (low CRH, high ACTH, cortisol)
adrenal cortex problem (low CRH, ACTH, high cortisol)