Flashcards in Hypothalamus and Temperature Regulation Deck (29):
Anatomically, what structures surround the hypothalamus?
The pituitary gland is inferior to it.
The optic chiasm is anterior to it.
The mammillary bodies are posterior to it.
True or false: the pineal gland is anterior to the thalamus.
False. It is posterior.
How does the hypothalamus control the somatic motor system?
Via efferent projections to autonomic control areas of the cortex and brainstem motor nuclei
True or false: parasympathetic innervation decreases the release of norepinephrine.
False. There is no parasympathetic innervation of the adrenal glands.
There are two hormones made and secreted by the hypothalamus: _____________. Describe the route they take.
oxytocin and vasopressin; they are made in the supraoptic and periventricular nuclei and are transported through axons to the blood vessels of the posterior pituitary (this is the direct pathway)
Visceral sensory information synapses on the _____________.
What are the neural inputs to the hypothalamus?
Direct from the retina
Fornix projections from the hippocampus
Visceral sensation from the solitary tract
Brainstem reticular nuclei (BP)
Stria terminalis connections with amygdala
Medial forebrain bundle (connects to frontal lobe)
What are the humoral inputs to the hypothalamus?
What is the superior end of the neural tube?
What is the milk letdown reflex?
Stimulation of the nipples (via neural stimulation) leads to release of oxytocin and subsequent release of milk
Decerebrating experiments in cats demonstrated that ______________.
they couldn't have the full "sham rage" (arching the back, hissing) response when the brainstem was separated from the hypothalamus; in contrast, sham rage was observed excessively when the hypothalamus was left connected to the brainstem but severed from the higher brain areas
Lesions of the ____________ lead to ravenous hunger, while lesions of the ____________ lead to lack of appetite.
ventromedial nuclei (in the hypothalamus); lateral hypothalamic area
Describe the idea of the setpoint in weight (as set by the hypothalamus).
The hypothalamus sets weight. If you give rats a high fat diet, they'll gain weight. If you give them back their normal diet, they'll return to their previous weight. The inverse happens with low calorie diets.
The _____________ nucleus coordinates the circadian rhythm.
What happens to the metabolic rate when the hypothalamus cools?
It increases to return the temperature of the hypothalamus back to its set point.
The anterior hypothalamus is the _______________ center.
"I'm too hot" (the area that motivates you to cool off)
The ______________ controls behavior that generate heat.
It generates vasoconstriction and shivering to warm up the body.
Where does the PGE2 that stimulates fever come from?
The OVLT (organum vasculosum of lamina terminalis) – a part of the POAH – which makes it in response to IL-1
Brown adipose tissue is important in keeping _________ warm.
infants and other small mammals
It does so by having its catabolism sped up when the anterior hypothalamus cools.
The __________ divides the hypothalamus into medial and lateral sections.
The hypothalamus controls the sympathetic and parasympathetic nervous systems via _______________.
neuronal projections to the lateral gray column (for sympathetic) and brainstem (for parasympathetic)
Oxytocin stimulates ______________.
contraction of smooth muscle in the uterus and breasts
Angiotensin II acts on the ____________ to stimulate thirst centers.
The arcuate nucleus is involved in _________.
sensing peripheral hormone levels
The posterior hypothalamus is the ____________ center.
"I'm too cold" (that is, it motivates you to seek warmth)
What is the POAH?
PreOptic Anterior Hypothalamus (the area that senses warmth)
Pyrogens act on the ___________ to stimulate fever.
POAH; they do so by decreasing activity of the thermoreceptors (thus tricking the body into thinking it is cooler than it actually is)
The indirect pathway controls release of _____________.
hormones made in the anterior pituitary