Lecture 08 - Hypothalamus Flashcards Preview

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Flashcards in Lecture 08 - Hypothalamus Deck (19):
1

Hypothalamic inputs

Viscerosensory
internal receptors ** homeostasis
retina
olfactory
amygdala ** physical expression of emotion
hippocampus

2

Circumventricular organs

fenestrated endothelial cells - part of BBB
-constantly monitor blood

3

Outputs

descending autonomics --> drive sympathetics
"head ganglion of the autonomic nervous system"

4

Regulation of endocrine system

Pituitary gland
also affects periphery via neuroendocrine system

5

Venous drainage

int. jugular

6

Regions

Mammillary region
tuberal region
supraoptic region

7

Paraventricular nucleus

Supraoptic region
-synthesize and secrete oxytocin and ADH --> post pit.
-oxytocin = uterine contractions, milk let-down, maternal bonding
-ADH = increase H2O reabsorption and increase BP
-CRF = release of cortisol from adrenal cortex (via portal system) --> increases energy demand and increases GNG

8

Supraoptic nucleus

Supraoptic region
-synthesize and secrete oxytocin and ADH, not CRF

9

Suprachiasmatic nucleus

Supraoptic region
-master of biological clock
inhibition decreases release of melatonin from pineal gland
darkness dis-inhibits = increase melatonin release

10

Melatonin

-release inhibited by light
-increased levels cause drowsiness, lower body temp

11

Seasonal affective disorder

SAD (late fall, early winter)
-symptoms: sluggish, anxiety, oversleeping, craving carbs, lethargy, depression
-treat by increased exposure to broad spectrum light (blue light) to suppress melatonin

12

Anterior hypothalamus

Supraoptic region
-necessary for heat dissipation (thermoregulation)
-descending autonomic arousal = sweating, vasodilation, panting

***lesion = hyperthermia
(aneurism in Ant. comm.)

13

Arcuate nucleus

Tuberal region
-Thyroid RH, CRF, Gonadotropin RH, Growth hormone RH, somatostatin (inhibits GH)

14

Ventromedial nucleus

Tuberal region
-satiety center

***lesion = hyperphagia (overeating), also rage-like outbursts (hypothalamic rage)

15

Leptin

neuropeptide secreted by adipocytes that bind to receptors in ventromedial nucleus to crub appetite
-deficiency results in morbid obesity
-reduced sensitivity to leptins may contribute to obesity

16

Lateral hypothalamic area (LHA)

"feeding center"

***lesion = aphagia (severe neglect of eating)

Medial forebrain bundle --> dopaminergic highway for rewards system, but also --> LHA

17

Orexin/Hypocretin

Excitatory neuropeptide secreted by lateral hypothalamus
-energy surge, increased arousal
-increases body temp, locomotion, respiration
-promotes wakefulness
-increases appetite

Neurons manage metabolic states during alert, active states and sleep (energy balance)
-highly active states require increased food
-monitor nutrional status to stimulate arousal and appetite when levels fall below set point
-dynamic between LHA and VMN to establish set point for body weight

18

Posterior hypothalamus

Mammillary region
-Head production, vasoconstriction, piloerection, shivering
-descending autonomics --> sympathetic drive

***lesion = hypothermia

19

Mammillary body

Mammillary region
-part of limbic system (limbic -> hippo -> fornix -> MB)

***lesion = Karsakoff's psychosis (problem with timeline of memories -> temporal encoding rather than retrieval)