Hypothalamic-Pituitary Relationships Flashcards
What are the connections between the hypothalamus and posterior pituitary?
LO1
hypophysial stalk: physical connection between the hypothalamus and pituitary gland
communication: neural signal. collection of axons in posterior pituitary - cell bodies in hypothalamus
- Supraoptic nucleus (SON)
- Paraventricular nucleus (PVN)
What does the posterior pituitary secrete? (From which part of hypothalamus?)
ADH (SON)
oxytocin (PVN)
What are the connections between the hypothalamus and anterior pituitary?
LO2
neural and hormonal
-connected by hypophysial portal system
How are hormones delivered to the anterior pituitary?
LO2/LO3
-directly delivered to the anterior pituitary in high concentrations through the hypothalamic-hypophysial portal system
What is a primary endocrine disorder?
LO4
low or high levels of hormone due to defect in the peripheral endocrine gland
What is a secondary endocrine disorder?
LO4
low or high levels of hormone due to defect in the pituitary gland
What is a tertiary endocrine disorder?
LO4
low or high levels of hormone due to defect in the hypothalamus
What is in the ACTH family?
corticotrophs - secrete ACTH
What is in the TSH, FSH, LH family?
thyrotrophs - secrete TSH
gonadotrophs - secrete FSH and LH
What is in the prolactin family?
somatotrophs - secrete GH
lactotrophs - secrete Pro
Describe the HPA axis
LO5 overview
- corticotrophs in anterior pituitary produce ACTH
- ACTH is under the stimulatory control of hypothalamus - CRH
- ACTH targets adrenal gland
- stress is a regulator of the HPA axis: neurogenic (fear) or systemic (infection, surgery)
HPA axis
major hypothalamic and pituitary hormones
LO5a
hypothalamic: CRH
anterior pituitary: ACTH
HPA axis
peripheral target organ
LO5b
adrenal gland
HPA axis
peripheral hormone
LO5c
cortisol
HPA axis
regulation of the axis
LO5d
stress
- neurogenic (fear)
- systemic (infection, surgery)
HPT axis
overview
LO6
TSH is released by thyrotrophs in the anterior pituitary
-TSH is a glycoprotein hormone
TSH is under the stimulatory control of the hypothalamus: TRH
TSH stimulates thyroid gland
Stress inhibits TRH secretion
HPT axis
major hypothalamic and pituitary hormones
LO6a
hypothalamic: TRH
anterior pituitary: TSH
HPT axis
peripheral target organ
LO6b
thyroid gland
HPT axis
peripheral hormones
LO6c
T4, T3
HPT axis
regulation of the axis
LO6d
stress (physical stress, starvation, infection) inhibits TRH secretion
HPG axis
overview
LO7
- FSH and LH released by gonadotrophs in anterior pituitary
- secreted into different secretory granules allowing independent secretion by gonadotrophs
- FSH and LH are under the stimulatory control of the hypothalamus: GnRH
- FSH and LH regulate the function of the gonads
HPG axis
major hypothalamic and pituitary hormones
LO7a
hypothalamic: GnRH
anterior pituitary (gonadotrophs): FSH and LH
HPG axis
peripheral target organs
LO7b
gonads
HPG axis
peripheral hormones
LO7c
FSH
males: sperm maturation in Sertoli cells
females: follicular development and estrogen synthesis in ovaries
LH
males: testosterone
females: estradiol, progesterone