Please enable JavaScript.
Coggle requires JavaScript to display documents.
hypothalamus: homeostasis (fluid regulation (VP receptors (V1b (also…
hypothalamus: homeostasis
temperature
neurons in the
medial preoptic area
of the hypothalamus detect changes in temperature
these neurons project to the
dorsomedial nucleus and the paraventricular nucelus
the
DMH
and
PVN
project to ANS nuclei which allows for correction of temperature
fever:
cytokines which are detected by OVLT causes the endothelium of OVLT to release
prostaglandin PGE2
, PGE2 is sensed by the medial preoptic neurons, they activate DMH and PVN to raise the temperature
circadian rhythms
the
suprachiasmatic nucleus
receives direct input from the retina and acts via the
PVN
and
DMH
to synchronize body circadian rhythms
melatonin is secreted by the pineal gland and it helps maintain sleep
sleep is actively engaged by the
ventrolateral preoptic nucleus (VLPo)
which inhibits signals from arousal promoting nuclei;
VLPo is disinhibited when SCN signal decreases
arousal is maintained by brainstem nuclei that project to the forebrain;
ascending reticular activating system
two populations of neurons in hypo. that promote arousal:
lateral hypothalamus neurons
that use orexin and the
tuberomammillary nucleus
(uses histamine)
fluid regulation
magnocellular
neurons in
PVN
and
supraoptic nucleus
are osmoreceptors
increased blood osmolarity increases firing rate of vasopressin neurons (magnocellular neurons)
ADH (vasopressin) stimulates the collecting tubule cells insert aquaporin which allows water to be reabsorbed
ADH also stimulates thirst centers in the
lateral hypothalamic nuclei
VP receptors
V1b (also called V3):
corticotropes, found in the brain
V2:
found on the collecting ducts
V1a (also called V1):
on vascular smooth muscle
ADH is also a vasoconstrictor via V1 receptors
eating
GLP-1 and PYY signal satiety
grehlin
(an acute signal of hunger) elicits eating via exciting
NPY/AgRP neurons
leptin signals the status of fat stores; leptin keeps you from eating
CCK (via the vagus) elicits meal termination
satiety peptides activate
POMC neurons
and
inhibit NPY neurons