Hypothalamus and Pituitary Flashcards
What are the general functions of the hypothalamus?
Homeostasis
Endocrine regulation
Autonomic regulation
Limbic system
What are the two subdivisions of the pituitary?
Anterior lobe/adenohypophysis
Posterior lobe/neurohypophysis
What are the regions of the hypothalamus?
Preoptic, anterior, tuberal, posterior
Anterior –> posterior
What are the zones of the hypothalamus?
Periventricular - thin layer of cells just inside the ependymal cell layer of the third ventricle
Medial
Lateral
What is the medial forebrain bundle?
Axonal pathway in the lateral zone that connects the vasal forebrain, hypothalamus and brainstem tegmentum
What part of the hypothalamus is involved in feeding and satiety?
Lateral hypothalamic area
Ventromedial nucleus -satiety center
What part of the hypothalamus is involved in sleep and circadian rhythms?
Ventrolateral preoptic area
Tuberomammillary nucleus - histamine neurons helps maintain waking state
Suprechiasmatic nucleus - receives light input, master clock
What part of the hypothalamus releases regulating factors that affect secretion from the anterior pituitary?
Arcuate nucleus
Paraventricular nucleus
Medial preoptic area
All project to the median eminence
What part of the hypothalamus release hormones from the posterior pituitary?
Suproptic nucleus and paraventricular nucleus
Release oxytocin and vasopressin
What parts of the hypothalamus are involved in autonomic control?
PAraventricular, dorsomedial, lateral, and posterior nuclei
What part of the hypothalamus is involved in memory?
Mammillary bodies
Part of memory forming circuit, implicated in Wernicke-Korsakoff syndrome
What parts of the hypothalamus are involved in thermoregulation?
Anterior hypothalamus - activates heat dissipation mechanisms
Posterior hypothalamus - activates heat conservation
What are the major inputs to the hypothalamus?
Visceral sensory - from spinal cord, solitary nucleus, anterolateral system
Blood properties - From circumventricular organs (outside BBB)
Light information - optic pathway
Integration of emotion with autonomic and homeostatic function, and memory formation - prefrontal and limbic areas, hippocampus and amygdala
What are the major outputs from the hypothalamus?
Regulates preganglionic autonomic neurons via output through the medial forebrain bundle
Connections to the prefrontal, limbic, himmocampus, amygdala - regulation of behavior
Output to pituitary for control of endocrine function
Describe the hypothalamic-pituitary-adrenal axis
Corticotropin releasing hormone from hypothalamus–>adrenocorticotropic hormone (ACTH) released from anterior pituitary –>Release of corticosteriod hormones from adrenal cortex
Cortisol feeds back to the hypothalamus and anterior pituitary
