Flashcards in Hypothalamus IV Deck (19)
Where is most corticotropin releasing hormone produced?
What does corticotripin releasing hormone do?
acts on coricotropes in the anterior pituitary which release ACTH (adrenocorticotropic hormone)
What does ACTH do?
acts on receptors in the adrenal gland to produce glucocorticoids for stress responses and cellular metabolism
Where does ACTH come frome?
cleavage of POMC.
What do glucocorticoids do? What time of day is it released?
regulate glycogen use and sortage
change heart rae
modulate immune responses
released mostly in the morning and least in the late afternoon.
What happens if you have an overactive gluocorticoid system?
Cushing's = too much glucocorticoids
can result in a camel hump, round face, high bp, bone loss, maybe diabetes
What happens if you have an underactive glucocorticoid system?
Addison's disease. This is a potentially fatal conditions. You see muscle weakness, fatigue, GI symptoms (when acute, this can be severe vomiting and diarrhea), skin changes (hyperpigmentation_
What do we see with depression in terms of the glucocorticoid system?
elevated CRH levels and decreased CRH receptor binding sites.
Where is gonadotropin releasing hormone produced?
anterior hypothalamus and preopitc area
What do goandotropes of the anterior pituitary produce?
LH and FSH
What does LH do?
stimulates the secretion of sex steroids from the gonads: in males, LH binds to Leydig cells and induces secretion of testosterone
In females, cells in the ovary secrete testosterone, which is coverted into estrogen by granulosa cells. Also, ovulation of mature follicles induced by the pre-ovulatory LH surge.
What hormones are required for pregnancy?
progesterone for maintenance of pregnancy. LH required for continued devolopment of corpora lutea.
What does FSH do?
stimulates the maturation of ovarian follicles.
critical for sperm production by supporing the Sertoli cells, which support sperm cell maturation.
In addition to estrogen, progesterone, and testosterone, what other hormones are secreted by the gonads? What are the effects of these hormones?
inhibit and ctivin which inhibit/activate FSH secretion from the pituitary.
When is GnRH released?
pulsatile constant release in males
release varies across a ~28 day cycle in males.
In males, there is classic negative feedback
In females, etradiol is a positive feedback agent causing a preovulatory GnRH surge. After ovulation, the negative feedback system comes back.
How do oral contraceptives work?
include estrogen and progesterone, which feedback on the pituitary/hypothalamus and inhibit LH surge that induces ovulation.
What is clomiphene?
fertility drug tha tincreases production of GnRH by inhibiting negative feedback of estrogen on the hypothalamus. Thus, the pituitary gland makes more FSH and LH, and more follicles in the ovaries are stimulated to grow.
From where is prolactin released? What is the releasing factor?
released from anterior pituitary. DA is probably the releasing factor (DA= dopamine), though other stuff works too.