Hypothalamus Flashcards
Hypothalamus-endocrine system fx
regulates hormone secretion from the pituitary ia direct neural projections to the posterior pituitary and via the synthesis of releasing and inhibiting hormones that reach the anterior pituitary via the pituitary portal circulation
Hypothalamus-autonomic nervous system fx
it does this via dsecending projections to the craniosacral/parasympathetic division or thoracolumbar/sympathetic
Hypothalamus-limbic system fx
the hypothalamus receives input from and projects to limbic structures including the hippocampus, amygdala and septal nuclei as well as the orbital cortex of the frontal lobe
What are the divisions of the hypothalamus?
preoptic, suprachiasmatic, tuberal and mammillary
What does the posterior pituitary do?
It secretes vassopressin and oxytocin.
Where are vasopressin and oxytocin synthesized?
They are synthesized in the paraventricular and supraoptic nuclei (hypothalamic nuclei). The large cells that synthesize and secrete oxytocin are part of the magnocellular system. The hormones are transpoted via axonal tranport to erminals in the posterior pituitary where they are stored until release. The hormones are synthesized as pro-hormones and cleaved during transport
What is the median eminence?
It is located at the base of the hypothalamus on the ventral surface. It contains a rich plexus of capillaries. Blood from this capillary plexus drains via portal vessels into a secondary plexus within the anterior pituitary, a true portal system. THere is no bbb here
What is the parvicellular neurosecretory system?
the relatively small neurons that secrete hypothalamic releasing and inhibiting factors.
What are hormones synthesized by the anterior pituitary?
Their release is modulated by the hypothalamus releasing and inhibiting hormones. LH, FSH, GH, ACTH, TSH
What is LHRH?
made by the hypothalamus, appears to release both LH and FSH
What is GHRH
it stimulates the release of growth hormone
What is GH-RIH
it inhibits the release of growth hormone
What is CRH?
it stimulates the release of adenocorticotropic hormone
What is TRH?
it stimulates the release of thyroid-stimulating hormone
How is the hippocampus and the hypothalamus connected?
the fornix
