Hypothalamus - Everything Flashcards
Posterior Nucleus; function & loc
Sympathetic output (fight or flight)
Thermogenesis
(posterior region)
Tuberomammillary nucleus; function & loc
Histamine sys - Promoting Wakefullness
posterior region
Fornix
memory consolidation
projects form hippocampus to mammillary bodies
(Posterior region of hypothalamus)
Mammillary body; function
memory consolidation
posterior region
Lateral Hypothalamus; function
feeding center
orexin sys - promoting wakefulness & appetite
(posterior region)
Posterior Nucleus lesion
Horner’s syndrome (myosis=constriction, anhidrosis, ptosis)
Poikilothermia
Tuberomammillary Nuc lesion
hypersomnia - sleepiness
Mammillary body lesion
anterograde amnesia
confabulation
Lateral hypothalamus lesion
anorexia
narcolepsy
Posterior Region - consists of;
Posterior nucleus
Tuberomammillary nuc
Mammillary body
Lateral hypothalamus
Tuberal Region - consists of;
Lateral Hypothalamus
Ventromedial nuc
Arcuate nuc
Dorsomedial nuc
Ventromedial nuc; function
satiety center
contains leptin-sensitive neurons
(tuberal region)
Ventromedial nuc; lesion
hyperphagia & obesity
leptin
increase conc in ventromedial nuc -> cessation of eating
Dorsomedial nuc; function
feeding & body weight regulation
may serve as relay center of energy homeostasis
lesion: feeding & body wt dysfunction
(tuberal region)
Dorsomedial nuc; lesion
feeding & body wt dysfunction
Arcuate nuclesu; function
Secretion of hypophyseal hormones
Feeding behavior (orexigenic & anoretic neurons)
(tuberal region)
Hypophyseal hormones
Controlled by Arcuate nuc
Released into median eminence to act on the Anterior Pituitary
- Tuberoinfundibular dopamine (TIDA) - release dopamine -> inhib prolactin
- Growth Hormone-releasing neurones (GHRH) - release GHRH -> inc secretion of GH
Orexigenic GABA/NPY/AgRP neurons
of the Arcuate Nuc (tuberal region)
Project into Lateral Hypothalamus
Promote feeding
Ghrelin (from stomach) promotes these neurons
Anoretic POMC/CART neurons
of Arcuate nuc (tuberal region)
Project into Lateral hypothalamus
Inhibits feeding
Leptin (from adipocytes) promotes inhibition
Leptin
secreted by adipocytes; reflects body fat stores
nutrient abudance; leptin increased -> dec appitite, inc energy expenditure
nutrient insufficiency; leptin decreased -> inc appetite & energy conservation
+ for POMC/CART
- for GABA/etc
Ghrelin
produced by stomach
stimulates eating
+ for GABA/etc
zones of the median eminence
internal zone - contains axons of magnocellular neurosec neurons of supraoptic nuc and paraventricular nuc that project into post pituitary
external zone - hypothalamo-pituitary portal system, nerve endings of neuroendocrine neurons (that control hormonal sec of the ant pituitary gland)
Types of neurons that project to the external zone of the median eminence
dopamine growth hormone releasing hormone somatostatin gonadotropin-releasing hormone corticotropin-releasing hormon thyrotropin-releasing hormone
Arcuate nucleus; lesion
neuroendocrine and feeding dysfunction
Dorsomedial nucleus; function
control feeding & body wt
Dorsomedial nucleus; lesion
feeding & wt dysfunction
Anterior supraoptic region; consists of
Anterior nuc Suprachiasmatic nuc Paraventricular nuc Supraoptic nuc Lateral hypothalamus
Anterior nuc; function
control of Parasymp
Thermoregulation (dissapation of heat)
(ant supraoptic region)
Anterior nuc; lesion
deficit in parasymp function
hyperthermia
(ant supraoptic region)
Suprachiasmatic nuc; function
Circadian rhythms
(bio clock & modulates pineal gland function)
(ant supraoptic region)
how does the suprachiasmatic nuc control circadian rhythms?
receives light info from retinal ganglion cells
via; Retinohypothalamic tract
info relayed via desc symp fibers from hypothal -> intermediolat nuc -> sup cervical ganglia -> pineal gland
Inhibits prod of Melatonin during day
(melatonin = sleep-promoting hormone)
Suprachiasmatic nuc; lesion
disturb cyclic variations of body functions blood pressure hormone levels body temp sleep & wakefulness
Paraventricular nuc; function
water retention (vasopressin secreting) milk letdown, uterine contraction (oxytocin secreting) control ant pituitary function (ACTH, TSH)
milk letdown & water retention
paraventricular nuc
magnocellular neurosec neurons project to Posterior Pituitary;
release Oxytocin or Vasporessin (ADH) in to general circulation
Vasopressin - inc water perm in collecting duct, activated by inc in osmolarity, circ levels of angiotensin, dec BP, hypovolemia
Oxytocin - stim of nipple -spinal pathways->hypothalamus = act of these neurons -> Oxytocin release => contraction of myoepithelial cells
paraventricular nuc; control of Ant Pituitary function
parvocellular neurosec neurons project to the median eminence/portal sys to control ant pituitary function;
Corticotropin-RH N - enhance adrenocorticotropic hormone (ACTH)
Thyrotropin-RH N - enhance thyroid-stimulating hormone (TSH) release
Somatostatin-R N - inhibit growth hormone secretion
Supraoptic nuc; function
water retention
milk letdown
uterine mm contraction
(ant supraoptic region)
Supraoptic nuc - how it works
paraventricular nuc
magnocellular neurosec neurons project to Posterior Pituitary;
release Oxytocin or Vasporessin (ADH) in to general circulation
- Just like the Paraventricular nuc (except doesn’t alter secretions of ACTH, TSH, or GH)
Orexin
orexen (hypocretin) neuropeptide regulator of sleep/wake states, feeding behav, reward process deficiency = narcolepsy * esp imp for maintenance of wakefulness admin of orexin stimulates appetite
Paraventricular nuc; lesion
diabete insipidus (same as Supraoptic nuc) endocrine deficits (unique to it)
(ant supraoptic region)
Supraoptic nuc; lesion
diabete insipidus (same as Paraventricular) - drink drink pee pee
(ant supraoptic region)
Anterior Preoptic region; consists of
lateral preoptic nuc
medial preoptic nuc
of telencephalic orgiin, but functionally associated w/ hypothalamus
*only part that the lateral hypothalamus isn’t present
nucleus basalis of Meyner
rich in cholinergic neurons w/ wide projections to neocortex
compromised in Alzheimer disease
located laterally to the Lateral preoptic nuc - the Substancia Inominata (in the Ant preoptic region)
Lateral preoptic nuc; function
Inhibits wakefulness
promotes non-REM sleep
(ant preoptic region)
Lateral preoptic nuc; lesion
hyposomnia
Lateral preoptic nuc; mechanism
GABAergic neurons in ventrolat preoptic inhibit wake-promoting;
Orexinergic neurons - lateral hypothalamus
Histaminergic neurons - posterior hypothalamus
Cholinergic, Serotonergic, & Noradrenergic Neurons - brainstem
= control global brain activity & promote non-REM sleep
Medial preoptic nuc; function
thermoregulation set point
release of gonadotrophic hormones (into med eminence) & sexual behavior
(ant preoptic region)
Medial preoptic nuc; lesion
hyperthermia
amenorrhea & impotence
(ant preoptic region)
body temp below the set-point
Medial Preoptic neurons activate Posterior hypothalamus (Symp)
= heat conservation via shivering and vasoconstriction
body temp above the set-point
Medial Preoptic Nuc activate Anterior Hypothalamic nuc
= sweating and vasodilation (Para)
Fever
set-point to a higher temp
triggered by pyrogens (cytokines) -> PGE2 (prostaglandin) -> act on Medial Proptic neurons to reset the set-point to a higher temp
Aspirin works by inhibiting the enzyme cyclooxygenase involved in prod of PGE2
Stria terminalis
connects reciprocally the hypothalamus and amygdala
hypothalamic-hypophyseal portal system
system where factorsl controlling the hormonal secretion of the Anterior Pituitary gland are released and reach their target via a portal venous system
supraoptico-hypophyseal tract
contains axons from the paraventricular and supraoptic nuclei projecting to the posterior pituitary gland
retinohypothalamic tract
carries light info from retinal ganglion cells to the Suprachiasmatic nuc
dorsal longitudinal fasiculus
- contains afferent hypothalamic fibers - carring visceral and tast sens; relayed to the hypoth via the solitary and parabrachial nuc
2 contains efferent hypoth fibers innervating; preganglionic parasym neurons, pregang symp neurons in spinal cord, autonomic reg centers in medulla, periaqueductal gray (pain modulation)
hypophyseal portal system links;
the hypothalamus and pituitary gland
allows endocrine signalling between the two structures
arteris of pituitary gland
superior and inferior hypophyseal arteries
superior hypophyseal artery
forms a capillary plexus, primary portal plexus, that penetrates the median eminence and infundibulum
primary portal plexus drains via long portal veins to the secondary portal plexus in the ant pituitary
inferior hypophyseal artery
forms capillary network within the posterior pituitary
venous drainage via hypophyseal veins
nuclei of Neuroendocrin control
paraventricular
supraoptic
arcuate
medial preoptic
nuclei of Weight Control, Feeding, Drinking
ventromedial
lateral hyp
arcuate
dorsomedial
nuclei of Temp Reg and Fever
medial preoptic
posterior
anterior
nuclei of Osmoreg, Water Balance, BP, B volume
posterior anterior paraventricular supraoptic CVO's
nuclei of Reproductive function
paraventricular
supraoptic
medial preoptic
nuclei of Sleep/Wake cycle
suprachiasmatic
tuberomammillary
ventrolateral preoptic nuc
