Questions Flashcards
Dexamethasone is a drug used to suppress the secretion of ACTH from the anterior pituitary. Two patients with hypersecretion of cortisol are given dexamethasone. Patient A’s cortisol secretion falls to normal levels as a result, but patients B’s cortisol level remains elevated. Which patient has primary hypercortisolism, explain your reasoning.
- always draw picture
Extra info:
> Trophic hormones and primary and secondary problems NB to remember
> Cause release and maintain downstream organ - remember cortisol is a neg feedback not trophic
- adrenal cortex = primary organ
- primary = something wrong in primary organ
Answer:
Patient B, cortisol level still high, even if ACTH secretion is inhibited
Hyposecretion from damage to the pituitary
Hypothalamus (CRH) - Increased
Ant pituitary (ACTH) - decreased
Adrenal cortex (cortisol) - decreased
Hyposecretion from atrophy ( decrease in size or wasting away of a body part or tissue) of the adrenal cortex
Hypothalamus (CRH) - Increased
Ant pituitary (ACTH) - Increased
Adrenal cortex (cortisol) - decreased
Would you expect the [ ] of TSH to be normal, above normal, or below normal in a person whose diet is deficient in iodine? Will this person have a goitre, why or why not?
- TRH (thyroid releasing hormone) = trophic hormone
-T3 and T4 need iodine, if deficient in iodine = low levels of T3 and T4 - this results in high levels of TSH and TEH due to negative feedback mechanism
- and yes, this would result in a goitre, because constant levels of TSH result in an increase in size of thyroid gland
A patient displays symptoms of excess cortisol secretion. What factors could be measured in a blood sample to determine whether the condition is caused by a defect at the hypothalamic/anterior pituitary level or the adrenal cortex level
measure the hormones secreted by the:
Hypothalamus (CRH) -
Ant pituitary (ACTH) -
Adrenal cortex (cortisol) - (increased)
If the levels of CRH and/or ACTH increased = problem
