Diencephalon Flashcards
(31 cards)
Embryological - diencephalon
Prosencephalon
Hypothalamus anatomy and boundaries
Surrounding 3rd ventricle…almina terminalis, hypothalamus sulcu, pituitary and midbrain
Medial and lateral divided by fornix
Fornix connects
Hypothalamus to hippocampus
Preoptic region structurs and function
Suprachiasmatic
Supraoptic
Paraventrciular
Preoptic nuclei
Suprachiasmatic involved in cricadian rhythams
Reflex for thirst ad nparturition and heat/cold detection
post vs anterior pituiary
Posterior is neurohypophysis that is a part of hypothalamus
Anterior is adenohypophysis that is a gland
Preoptic hypothalamus and posterior pituiary path
Paraventricular and supraoptic nuclei synthesize vasopressin (ADH) and oxytocin…hormones transmitted to posterior poiuitary along the supraopticohypophyseal tract
2 important circumventricular organs
organ vasculusom - osmoreceptors (increase results in depolarization)
Median eminence - temperuature
Thirst reflex pathway (example when too high)
Tonicity too high…sensed by organ vasculusom…preoptic nuclei release ADH into blood stream
Parturition reflex pathway
Pressure on cervix…preoptic neurons release oxytocin…positive feedback loop with contractions of cervix…similar from mmary glands from suckling
Tuberal region structures and function
Dorsomedial
Ventromedial
Arcuate
Hunger/satiety
Tuberal hypothalamus and anterior pituitary
Arcuate contains neursecretory cells that synthesize signaling hormones…transported along tuberinfundibular tract to anterior pituitary…can increase or decrease production of specific anteiror pituiary hormones
Hormones of anterior pituiary
ACTH (cortisol - symp)
TSH (metab)
GH (bone frowth)
LH/FSH - reproductive and testosterone
Feeding path general
Lateral area is feeding center (NPY)
Ventromedial is satiety center (POMC_
Feeding when hungry
Declining fat stores stimulate release of more ghrelin and less leptin…ghrelin binds NPY of arcuate nucleus…excitatory to lateral and inhibtory to medial
Feeding when full
More lepti nand less ghrelin released…leptin binds POMC in arcuate…excitatory to ventromedial and inhibitory to lateral
Mamillary region (caudal)
Sympathetic functions and some memory (mammillary)
Autonomics of hypothalamus and 3 major tracts
Anterior-medial - parasynpathetic
Posteiror - lateral - sympathetci
DLF
hypothalamo-spinal tract
Medial froebrain bundle
Inputs to hypothalamus regarding autonomic pathways
Septal region via medial forebrain bundle
Amygdala via stria terminalis
Hippocampus via fornix
Mostly based on emotional state
Para vs. symp at skin
No parasympathetic innervation at skin so must use sympathetic
Temp pathway general
Preoptic region contains head and cold sensitive neurons
When temp decrease
Cold sensitive neurons signal posterior hypothalamis centers for shivering and constriction of skin vessels…excitatory connections with IML nuclei
When temp increases
Heat sensitive neurons signal posterior hypothalamic centers for sweating…excitatory for IML related to sweat…inhibitory to skin vessel constriction
Hypothalamus blood supply
Circle of willis
Childhood weight disorders
underproduction of leptin can lead to obesity
Tx with synthetic leptin hormone
