diencephalon - hypothalamus

• endocrine functions of the hypothalamus (physiological coordination)

  • by the release form neurons in various hypothalamic nuclei of specific releasing hormones
  • control thyroid, adrenal gland and gonads
  • regulate GH and PRL secretion
  • regulate oytocin (uterine contractions, lactation) and vasopressin (water balance) release from the posterior pituitary
• non-endocrine functions of the hypothalamus (homeostatic/external -> internal coordination)

  • regulate body temperature
  • regulate food intake
• hypothalamus is concerned with:

  • growth
  • reproduction
  • metabolism
• hypothalamus integrates sensory, cognitive and emotional information to regulate endocrine, autonomic and behavioral responses
• • receive information from afferents
  • ascending sensory signals from the brainstem and spinal cord
  • descending information form the cortex and limbic system
  • send information through efferents and through hormones
  • connections to other brain structures
  • efferents to autonomic nervous system
  • direct and less direct connection to pituitary
  • release of hormones
• • pituitary gland is connected to the hypothalamus by the axons of neurons coming down to terminate in the posterior pituitary
• • anterior pituitary: not connected to hypothalamus; receives signals (mostly releasing hormones) from hypothalamus via the portal blood supply; releases hormones into general circulation
  • actual "gland" part of the pituitary
• • posterior pituitary: continuous with hypothalamus; releases hormones made from certain areas of the hypothalamus into the general circulation
• rostral caudal axis of the nuclei in the hypothalamus:

  • preoptic area
  • supraoptic/anterior hypothalamus
  • middle hypothalamus
  • posterior hypothalamus
• preoptic area: medial preoptic nucleus
• supraoptic/anterior hypothalamus: suprachiasmatic nucleus (SCN); paraventricular nuleus (PVN); periventricular nucleus; supraoptic nuclei (SON)
• middle hypothalamus: arcuate nucleus; ventromedial nucleus and median eminence
• posterior hypothalamus: arcuate nucleus, tuberomammillary nucleus, mammillary region
• anterior nucleus: body temperature regulation