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Neuro - Hypothalamus


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Name the lateral hypothalamic nuclei (rostral to caudal)
Lateral preoptic nuc -> lateral hypothalamic nuc (and MFB)
Name the medial hypothalamic nuclei (rostral to caudal)
Medial preoptic nuc -> suprachiasmatic nuc/supraoptic nuc/anterior nuc/paraventricular nuc -> dorsomedial nuc/ventromedial nuc/arcuate nuc -> mamillary bodies/posterior nuc
What are the 4 hypothalamic divisions (rostral to caudal)?
Preoptic area, anterior (supraoptic) region, middle (tuberal) region, posterior (mamillary) region
4 main types of hypothalamic functions?
Homeostatis, Endocrine, Autonomic, Limbic (HEAL)
What is the embryologic origin of the hypothalamus?
Diencephalon, except for preoptic area, which is from telencephalon
What are the functions of the preoptic area?
regulates release of gonadotropic hormones, and contains sexual dimorphic nucleus (development of which depends on testosterone levels)
What occurs with a lesion of the preoptic area, before and after puberty?
before puberty: arrested sexual development

after puberty: amenorrhea or impotence
What is the function of the suprachiasmatic nucleus?
regulates circadian rhythms
To what nucleus does the retina project directly?
suprachiasmatic nucleus
What are the functions of the anterior nucleus?
thermal regulation (activates DISSIPATION of heat), stimulates parasympathetic NS
Destruction of what nucleus results in hyperthermia?
anterior nucleus
What are the functions of the supraoptic and paraventricular nuclei?
synthesizes ADH and oxytocin, regulates water balance
Destruction of what nucleus causes diabetes insipidus, and what is this disease characterized by?
paraventricular and supraoptic nuclei; polydipsia and polyuria
What is the main nucleus that projects fibers to autonomic nuclei of the brainstem and spinal cord?
paraventricular nucleus (via medial forebrain bundle)
To what structure do the supraoptic and paraventricular nuclei directly project?
Posterior pituitary, where they release oxytocin and vasopressin
What is the main fucntion of the dorsomedial nucleus?
stimulation results in savage behavior and obesity
What is the function of the ventomedial nucleus?
satiety center (inhibits urge to eat when stimulated)
Lesion of what nucleus causes obesity and savage behavior?
ventromedial nucleus
Stimulation of what nucleus causes obesity and savage behavior?
dorsomedial nucleus
What is the function of the arcuate nucleus?
produces hypothalamic releasing and inhibiting factors
What tract does the arcuate nucleus give rise to?
tuberohypophyseal tract (terminates in hypophyseal portal system of infundibulum)
What nucleus produces DA, and what hormone does the DA inhibit?
arcuate nucleus; DA = prolactin-inhibiting factor
What are the input and output tracts for the mamillary bodies?
input from hippocampus via postcommissural fornix; output to AN of thalamus via mamillothalamic tract
What syndrome is characteristic of mamillary body lesions, and what is this syndrome caused by?
Wernicke's encephalopathy; caused by vitamin B12 deficiency
What are the functions of the posterior hypothalamic nucleus?
temperature regulation (conserves heat when stimulated), and stimulates sympathetic NS
What condition results from a posterior hypothalamic lesion?
poikilothermia (inability to thermoregulate)
What is the function of the lateral hypothalamic nucleus?
feeding center (stimulation induces eating)
Lesion of what nucleus causes anorexia/starvation?
Lateral hypothalamic nucleus
What structures does the stria terminalis connect?
septal area, hypothalamus, amygdala
What structures does the supraoptichypophysial tract connect?
Supraoptic/paraventricular nuclei to the neurohypophysis (post pit)
What structures does the tuberohypophysial tract connect?
connects arcuate (tuberal) nucleus to the hypophysial portal system (ant pit)
What 2 nuclei regulate food intake?
Ventromedial (satiety center) and lateral hypothalamic (feeding center)
What 2 nuclei regulate temperature and autonomic function?
Anterior nucleus (dissipates heat, stimulates parasympathetic), and posterior nucleus (conserves heat, stimulates sympathetic)
What is a Craniopharyngioma? Symptoms?
congential tumor from remnants of Rathke's pouch, usually calcified (usu in kids)

sx: bilateral hemianopia, hypothalamic syndrome
What is the most common supratentorial tumors in kids, and most common cause of hypopituitarism in kids?
What is a pituitary adenoma? Sx?
pituitary tumor in adults

sx: bitemporal hemianopia, hypothalamus syndrome, may cause endocrine abnormalities (e.g. amenorrhea, galactorrhea)
What are the symptoms of a "hypothalamic syndrome"?
adiposity, diabetes insipidus, disturbance of temperature regulation, somnolence
What part of the pituitary gland is part of the nervous system (innervated by the hypothalamus), and what part is glandular epithelium?
Adenohypophysis (ant pit) = glandual tissue

Neurohypophysis (post pit) = nervous tissue
What is arterial blood supply to the pituitary?
superior hypophysial arteries (from the circle of willis) to form primary capillary plexus in stalk

inferior hypophysial arteries supply posterior pit, and secondary capillary plexes drain distal regions of pituitary to the cavernous sinus
How do "direct" and "indirect" neuroendocrine secretion differ?
direct: from magnocellular nuclei (paraventricular and supraoptic) via neurohypohysis (no amplification)

indirect: from arcuate nuc and others, via portal vessels and adenohypophysis (w/amplification)

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