Lecture 16 2/15/24

Question 1

What are the components of the endocrine system?

Answer 1

-hypothalamus
-pituitary gland
-endocrine glands
-hormones
-target glands/tissues

Question 2

Which nuclei in the hypothalamus are responsible for hormone production?

Answer 2

-paraventricular nucleus
-supraoptic nucleus
-superchiasmatic nucleus
-arcuate nucleus

Question 3

What are the characteristics of ADH and oxytocin production/secretion?

Answer 3

-produced by supraoptic and paraventricular nuclei
-secreted in response to electrical activity
-travel down axons to posterior pituitary

Question 4

What are the characteristics of CRH/TRH/GHRH/GHIH/GnRH/PIH/PRH production?

Answer 4

-produced by paraventricular, suprachiasmatic, and arcuate nuclei
-secreted in response to electrical activity and circulating hormones
-enter hypothalamo-hypophyseal portal system to anterior pituitary

Question 5

What does the adenohypophysis/anterior pituitary originate from?

Answer 5

oral ectoderm

Question 6

What does the neurohypophysis/posterior pituitary originate from?

Answer 6

neural ectoderm

Question 7

Which portion of the endocrine system is referred to as the “master gland”?

Answer 7

pituitary

Question 8

What is a negative feedback loop?

Answer 8

action of the hormones directly or indirectly inhibits further secretion

Question 9

What is a positive feedback loop?

Answer 9

action of the hormones directly or indirectly promotes further secretion

Question 10

What is the adrenal loop?

Answer 10

-hypothalamus produces CRH to stim. pituitary
-pituitary produces ACTH to stim. adrenal glands
-adrenal glands release cortisol into systemic circulation
-cortisol also inhibits hypothalamus and pituitary

Question 11

What is the thyroid loop?

Answer 11

-hypothalamus produces TRH to stim. pituitary
-pituitary produces TSH to stimulate thyroid
-thyroid releases T4 and T3 into systemic circulation
-T4 and T3 also inhibit hypothalamus and pituitary

Question 12

What is the ovarian loop?

Answer 12

-hypothalamus produces GnRH to stim. pituitary
-pituitary produces LH and FSH to stim. ovaries
-ovaries release estrogen into systemic circulation
-estrogen inhibits hypothalamus
-estrogen can inhibit or promote pituitary
-ovaries also produce inhibin to inhibit pituitary

Question 13

What is the testicular loop?

Answer 13

-hypothalamus produces GnRH to stim. pituitary
-pituitary produces LH and FSH to stim. testes
-testes release testosterone into systemic circulation
-testosterone inhibits hypothalamus and pituitary
-testes also produce inhibin to inhibit pituitary

Question 14

What is the GH loop?

Answer 14

-hypothalamus produces GHRH to stim. pituitary, or somatostatin to inhibit pituitary
-pituitary produces GH to stim. liver and bone
-liver produces somatomedins to stim. bone
-somatomedins inhibit pituitary
-somatomedins stim. hypothalamus to produce somatostatin

Question 15

What is the prolactin loop?

Answer 15

-hypothalamus produces PRH to stim. pituitary or dopamine to inhibit pituitary
-pituitary produces prolactin to stim. utter
-prolactin inhibits pituitary
-prolactin promotes hypothalamus to produce dopamine

Question 16

What is the oxytocin open loop?

Answer 16

-hypothalamus released oxytocin directly into circulation with no pituitary involvement
-nursing and cervix stim. have a neuroendocrine reflex on hypothalamus

Question 17

What is the ADH open loop?

Answer 17

-hypothalamus releases ADH straight into circulation with no pituitary involvement
-changes in serum osmolarity and/or BP act on hypothalamus