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 –> neurohypophusis –> 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 Dopamine --> 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
- 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
- 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 nucleus
heat conservation
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)
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
- LHA
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 nucleus
feeding center
leptin receptors are present on _________ nucleus
leptin receptors are present on ARCUATE nucleus
