Lecture 16 2/15/24 Flashcards
What are the components of the endocrine system?
-hypothalamus
-pituitary gland
-endocrine glands
-hormones
-target glands/tissues
Which nuclei in the hypothalamus are responsible for hormone production?
-paraventricular nucleus
-supraoptic nucleus
-superchiasmatic nucleus
-arcuate nucleus
What are the characteristics of ADH and oxytocin production/secretion?
-produced by supraoptic and paraventricular nuclei
-secreted in response to electrical activity
-travel down axons to posterior pituitary
What are the characteristics of CRH/TRH/GHRH/GHIH/GnRH/PIH/PRH production?
-produced by paraventricular, suprachiasmatic, and arcuate nuclei
-secreted in response to electrical activity and circulating hormones
-enter hypothalamo-hypophyseal portal system to anterior pituitary
What does the adenohypophysis/anterior pituitary originate from?
oral ectoderm
What does the neurohypophysis/posterior pituitary originate from?
neural ectoderm
Which portion of the endocrine system is referred to as the “master gland”?
pituitary
What is a negative feedback loop?
action of the hormones directly or indirectly inhibits further secretion
What is a positive feedback loop?
action of the hormones directly or indirectly promotes further secretion
What is the adrenal loop?
-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
What is the thyroid loop?
-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
What is the ovarian loop?
-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
What is the testicular loop?
-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
What is the GH loop?
-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
What is the prolactin loop?
-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