Hypothalamus

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Hypothalamus
Saggital section of brain, with hypothalmus lying essentially between mammillary bodies (corpora mammillaria) and optic chiasma

System:
Function: Neuroendocrime regulation
Origin:
Branches:
Insertion:
Arterial supply:
Blood supply of brain
Venous drainage:
Lymphatic drainage:
Innervation:
Vertebral levels:
Search for Hypothalamus in Gray's.

The hypothalamus is the key organ regulating body homeostasis and is a region of cerebral nuclei with diverse and multiple neuroendocrine function anterior to the brain stem.

Anatomy

Approximate relationships of some of the hypothalamic nuclei
Hypothalamus in relation to pituitary

It includes the subthalamic tegmental region and the structures related to most of the floor of the third ventricle such as the mammillary bodies and infundibulum superior to the pituitary and optic chiasma.

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Neurophysiology

The hypothalamus controls body temperature, hunger, thirst, emotional and reproductive responses and circadian cycles. Parts of the hypothalmus such as the neurohypophysis, the median eminence, subfornical organ and the OVLT do not have a blood brain barrier to enable such regulation. There appears to be active uptake of other hormones such as prolactin and leptin in the choroid plexus from blood into CSF to also aid regulation. There is wide neuron input from:

These functions include (some can only be postulated from mammals which have say different reproductive physiology from humans):

  • Pheromonal cues
  • Neuron reaction to circulating peptide hormones
  • Modulation of hypothalamic neurons by steroids and glucocorticoids
  • Oxytocin secretion modulation by neuron stimulation nipples and genitals
  • Vasopressin secretion modulation by chemoreceptors in the carotid sinus and aortic arch, and from low-pressure atrial volume receptors*
  • Prolactin secretion modulated by projections from genitals and nipples.
  • Vagal modulation of cardiovascular and visceral stimuli

Endocrinology