Hypothalamus Flashcards
3 zones of hypothalamus
periventricular, medial, lateral
lateral zone nuclei
lateral preoptic nucleus, lateral hypothalamic area, tuberomammillary nucleus
lateral preoptic nucleus
anterior portion, “telencephalic”
lateral hypothalamic area
feeding center (induces eating when stimulated), contains melanin-concentrating hormone, orexins
tuberomammillary (lateral tuberal) nucleus
release histamine as a neurotransmitter to forebrain (wakefulness, attention/arousal). inhibited during sleep
medial zone
preoptic, anterior (supraoptic), middle (tuberal), posterior (mammillary)
preoptic region
anterior. contains medial preoptic nucleus that regulates gonadotropin secretion. also contains interstitial nuclei, of one is sexually dimorphic
anterior (supraoptic) region
contains 4 nuclei: suprachiasmatic nucleus, anterior hypothalamic nucleus, paraventricular nucleus, supraoptic nucleus
suprachiasmatic nucleus
dorsal to optic chiasm, gets direct input from retina. circadian rhythm.
anterior hypothalamic nucleus
between suprachiasmatic and paraventricular nuclei. temperature regulation/heat dissipation. lesion = hyperthermia. also parasympathetic drive of ANS
paraventricular nucleus
arginine vasopressin, oxytocin, CRH. excitation to sympathetic preganglionic neurons
supraoptic nucleus
AVP, oxytocin. project to neurohypophysis, released into circulation.
middle (tuberal) region
dorsomedial nucleus, ventromedial nucleus, arculate nucleus
dorsomedial nucleus
BP regulation. stimulation = aggression
ventromedial nucleus
inhibits urge to eat. relays ingestion-related signals to brainstem. lesion = hyperphagia
arcuate nucleus
projections to median eminence and portal vessels, controls release/non-release of adenophypophyseal hormones. feeding behaviors.
posterior (mammillary) region
posterior nucleus, mammillary nucleus
posterior nucleus
thermoregulation. lesion = inability to regulate (poikilothermia)
mammillary nucleus
part of limbic system. input from hippocampus via fornix. project to anterior nucleus of thalamus via MTT. damage = memory disturbances. also get sensory input
periventricular zone
contains periventricular nucleus. line walls of third ventricle. sort of part of medial zone nuclei.
fornix tract
hippocampus to mammillary bodies
mammillothalamic tract
from mammillary bodies to anterior nucleus of thalamus (part of Papez)
stria terminalis
amygdala connected to medial zone of hypothalamus
medial forebrain bundle
50 pathways. throughout entire lateral hypothalamic zone, from septal nuclei to brainstem
supraopticohypophyseal tract
from supraoptic and paraventricular nuclei to neurophypophysis (posterior pit). magnocellular axons, synth of AVP/oxytocin
tuberoinfundibular tract
from arcuate nucleus to hypophyseal portal system at median eminence. take neuropeptides made in hypothalamus to posterior pituitary, which then act on anterior pituitary cells
hypothalamospinal tract
descending axons regulate spinal cord preganglionic neurons from both ANS division. primarily from paraventricular nucleus. lesion = Horners
major regulatory functions of hypothalamus
body temperature, emergency responses to stress, feeding and energy metabolism, BP and electrolyte composition, reproductive functions
thermoregulation
anterior = warmth sensation, heat dissipation; posterior = cold sensitive, heat conservation
stress responsiveness
fight or flight. increases sympathetic, decreases parasympathetics. interconnections from many regions including amygdala and hippocampus
feeding and energy metabolism.
central role from arcuate nucleus. output integrated at NTS
agouti-related peptide and neuropeptide Y
signal increased feeding, decrease in metabolism
MSH (POMC) and CART
activation = decreased feeding, increased metabolism
ghrelin
stimulates feeding/food intake
PPY
inhibits feeding
leptin
released by fat cells, signals decrease in feeding (insulin is similar)
CCK
satiety
orexin and MCH
increase feeding
CRH re: stress and central oxytocin secretion
inhibit feeding
craniopharyngioma
congenital tumor in kids, grows up toward optic chiasm (pressure –> bitemporal hemianopia), hypothalamic syndrome (adiposity, diabetes, temp regulation issues, sleepiness)
memory disturbances
posterior hypothalamic lesions involving mammillary comples: inability to form new memories, eg korsakoff syndrome (thiamine deficiency, chronic EtOH)
klein-levin syndrome
adolescent males, hypothalamic lesion. compulsive eating, hypersomnolence, hypersexuality (may be from decrease in dopaminergic tone during symptomatic phase)
