Hypothalamus Flashcards
hypothalamus regulates ____________
hypothalamus regulates WHOLE BODY HOMEOSTASIS
-ensures survival of individual and of species
hypothalamus regulates whole body homeostasis via regulation of:
- ANS
- endocrine system
- somatic motor activity (drive-related behaviors)
internal parameters that the hypothalamus maintains the set point for
- temperature
- pH
- water
- glucose concentration
- many others
behaviors that the hypothalamus affects
- feeding
- drinking
- reproductive
SURVIVAL of individual and of species
anterior border of the hypothalamus
lamina terminalis
what separates the thalamus from the hypothalamus?
hypothalamic sulcus
circumventricular organs
- no BBB
- –fenestrated capillaries instead of tight junctions)
- allow exchange of substances btwn blood and brain (imp bc hypothalamus responsible for whole body homeostasis)
w/ hypothalamus
- median eminence
- neurohypophysis
- organum vasculosum
what causes hypothalamic disturbances
- inflammation
- tumors
- vascular disorders
- hydrocephalus
clinical disorders associated with hypothalamic lesions
- hyper/hypothermia
- obesity/wasting
- diabetes insipidus
- disturbances of sleep
- emotional disorders
- hypogonadism and early puberty
- altered growth patterns
sites associated with parasympathetic function tend to be located in _________ hypothalamus
sites associated with parasympathetic function tend to be located in ANTERIOR hypothalamus
preoptic area, anterior hypothalamus
sites associated with sympathetic function tend to be located in _________ hypothalamus
sites associated with sympathetic function tend to be located in POSTERIOR hypothalamus
lateral and posterior hypothalamus
______ and ______ systems modulate hormone synthesis/release from posterior/anterior lobes of pituitary
MAGNOCELLULAR and PARVICELLULAR systems modulate hormone synthesis/release from posterior/anterior lobes of pituitary
magnocellular system
- comprised of PVN (paraventricular) and SON (supraoptic) nuclei
- LARGE diameter neurons synthesize hormones (oxytocin, ADH)
- hormones transported to POSTERIOR pituitary for release into systemic circulation
vasopressin
water reabsorption by kidney
- synthesized by magnocellular system
- released by posterior pituitary
oxytocin
milk letdown, uterine contraction, pair bonding
- synthesized by magnocellular system
- released by posterior pituitary
lactation reflex
afferent = _________
efferent = _________
lactation reflex
afferent = NEURAL
efferent = HORMONAL (oxytocin)
-neural stimulus from baby suckling –> dorsal column –> neurohypophysis –> oxytocin released –> milk letdown
parvicellular system
- anterior lobe
- SMALL diameter hypothalamic neurons produce releasing and inhibiting factors that modulate synthesis and secretion of ANTERIOR pituitary hormones
- influences the pituitary via vasculature (hypophyseal portal vessels)
hypophyseal portal system
-delivers hypothalamic releasing and inhibiting factors to the anterior pituitary
hypothalmic substances that inhibit/stimulate release of pituitary hormones (and their pituitary correlate)
GnRH --> FSH, LH GHRH --> GH Somatostatin --> GH (inhibitory) TRH --> TSH DA --> prolactin (inhibitory) CRH --> ACTH
CRH
- released by hypothalamus
- in response to stress
- causes ACTH release from pituitary
- ACTH: cortisol release from adrenal gland
- feedback signal = cortisol
______ acts as a feedback signal for CRH release
CORTISOL acts as a feedback signal for CRH release
T/F: hypothalamic nuclei stain differently and can be distinguished on a stained section
false. cannot distinguish them on a stained section
medial preoptic area
prepotic area=rostral region of hypothalamus
- temperature regulation
- male sex behavior
- parental behavior
- sexually dimorphic nucleus
anterior/supraoptic hypthalamic region contains which nuclei?
- superchiasmatic nucleus
- paraventricular/supraoptic nuclei
- anterior nucleus
superchiasmatic nucleus
- master clock of brain
- day/night rhythms
- retinal input
paraventricular and supraoptic nuclei
- synthesis of oxytocin and vasopressin
- autonomic regulation
- stress axis
- metabolism
anterior nucleus
- temperature regulation
- heat dissipation
tuberal region of the hypothalamus contains which nuclei?
- VMN (ventromedial)
- DMN (dorsomedial)
- LH (lateral hypothalamic)
- arcuate
- periventricular
arcuate nucleus
food intake and metabolism
periventricular nucleus
reproductive cycles
bilateral lateral hypothalamic (LH) lesion causes
-anorexia
bilateral VMN lesion
ventromedial hypothalamic nuclei
- no satiety (voracious appetite)
- rage
leptin
- hormone produced by fat tissue
- acts in brain to modulate food intake
- functions in feedback loops that regulate metabolism and body weight
decreased leptin levels
- increased orexigenic peptides
- stimulation of feeding behavior (LH)
- decreased metabolism
elevated leptin levels
- stimulation of anorexic peptides
- inhibition of feeding behavior (LH)
- increase in metabolism
posterior region of hypothalamus contains which nuclei?
- mamillary bodies
- posterior nucleus
- subthalamic nucleus
- lateral hypothalamic nucleus
Korsakoff’s Syndrome
- destruction of mamillary bodies (and DMN)
- causes confabulatory amnesia
- associated with poor diet and alcoholism
posterior hypothalamic nucleus
heat conservation
centers for heat dissipation vs heat conservation
Dissipation:
- preoptic area (POA)
- anterior hypothalamic area (AH)
Conservation
-posterior hypothalamus
afferents to hypothalamus
- hippocampus
- amygdala
- septal nuclei
- other limbic structures
- retina
- spinothalamic
- visceral nuclei
- physical stimuli
which nuclei control endocrine system?
- supraoptic nucleus (SON)
- PVN (periventricular)
(synthesize oxytocin and vasopressin)
which nuclei control ANS?
-PVN (periventricular)
descending projections to craniosacral/thoracolumbar regions
which nuclei control body temp?
- anterior (AH)
- POA (preoptic area)
which nuclei control day night rhythms?
-SCN (superchiasmatic)
which nuclei control food intake and metabolism?
- VMH
- arcuate
- DMH
- PVN (paraventricular nucleus)
- LHA (lateral hypothalamic area)
which nuclei control sleep wake cycles?
- AH (anterior)
- POA (preoptic area)
- posterior hypothalamus
-melatonin
median eminence
- swelling on base on hypothalamus on ventral surface
- has rich plexus of capillaries
- connects hypothalamus to pituitary
- circumventricular organ (no BBB)
tuberoinfundibular tract
-collection of axons carrying releasing/inhibiting factors to the median eminence
VMN
satiety center
lateral hypothalamic (LH) nucleus
feeding center
leptin receptors are present on _________ nucleus
leptin receptors are present on ARCUATE nucleus
hypothalamus sits just superior and posterior to the
optic chiasm
efferents from hypothalamus
amygdala
septal nuclei
other limbic
thalamus (anterior nucleus, also dorsomedial)
pituitary gland
visceral motor nuclei (P,S)
