Hypothalamus - Bales Flashcards
Where is the major source of histamine in the CNS? What is this nucleus involved in?
the tuberomammillary nucleus of the LHA
this nucleus is involved in wakefulness (cortical arousal)
antihistamines will inhibit these neurons causing drowsiness.
What is produced ONLY in the lateral hypothalamus of the CNS? What does this play a role in? What does a dysregulation of this circuit cause?
orexin.
wakefulness
narcolepsy
What will stimulation of the lateral hypothalamus cause (in terms of food intake)? What about a lesion?
stimulation: hyperphagia (overeating)
lesion: anorexia
What is the role of the ventromedial hypothalamus? What would stimulation of the ventromedial hypothalamus cause? what about a lesion?
satiety center (determines when to stop eating)
stimulation==> anorexia (inhibits eating)
lesion==> hyperphagia (overeating)
What are anorexigenic and orexigenic molecules? How do they gain axis to the hypothalamus?
Anorexigenic (leptin) and orexigenic (ghrelin)
they gain access through the median eminence, one of the leaky-capillaried circumventricular organs (CVO)
What is the suprachiasmatic nucleus involved in? What does its output stimulate?
circadian rhythms
output stimulates pineal to secrete melatonin in the dark
What is the anterior hypothalamic nucleus involved in?
temperature regulation
anterior area has heat and cold sensitive neurons
at high temperature, it causes vasodilation and sweating to cause heat dissipation
How does the posterior hypothalamic nucleus regulate temperature?
causes heat conservation/production when the blood temperature is low
vasoconstriction and shivering
What can stimulation of the dorsomedial hypothalamic nucleus cause?
defensive-aggressive behaviors (“sham-rage”) in the absence of any contextual elicitors.
What are the two parts of the pituitary and what causes their difference in appearance in an H and E stain?
Adenohypophysis is secretory cell rich (dark, cell bodies stained with H&E)
Neurohypophysis is axon rich (pale, poorly stained with H&E)
Which 2 nuclei are involved in neuroendocrine regulation via the posterior pituitary? What pathway do they take to secrete hormones?
supraoptic and paraventricular nuclei
oxytocin and ADH are transported via the supraopticohypophyseal tract axons (magnocellular) to the posterior pituitary
nn terminals release hormones near the inferior hypophyseal A capillaries
What is the stimulus for the ADH secretion?
osmolality detecting neurons of the organum vasculosum of the lamina terminals (OVLT)
What is major function of the medial forebrain bundle (MFB)?
transmitting feedback from cervix (prepartum–> when cervix is distended) and breast (postpartum–> from suckling on the breast) to hypothalamus to stimulate oxytocin release
What is the paraventricular nucleus involved in? What would a lesion here cause?
it is a main regulator of the autonomic system (projecting to PNS and SNS preganglionic neurons)
Lesion here would cause ipsilateral Horner’s syndrome
Which 2 nuclei are involved in neuroendocrine regulation via the anterior pituitary? Where do their axons terminate?
preoptic and arcuate nuclei (parvicellular)
axons terminate on the superior hypophyseal A capillaries in the median eminence –> dump regulatory hormones into the portal veins causing
