Lecture 47: Hypothalamus Flashcards Preview

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Flashcards in Lecture 47: Hypothalamus Deck (26):
1

Hypothalamus regulates (6)

Homeostasis, temperature, hunger/thirst, emotional states, circadian rhythms/sleep/wake, reproduction

2

Preoptic area and anterior hypothalamus functions (4)

Thermoregulation (fever is generated here), fluid/electrolyte balance, sexual behavior, sleep!

3

The ventrolateral preoptic area is crucial for...

Sleep

4

Suprachiasmic nucleus is important for...this is based on what cycle?

Circadian rhythms; light/dark cycle

5

Arcuate nucleus

Feeding/body weight via NPY, AgRP, alphaMSH; neuroendocrine via DA (prolactin), GHRH (growth hormone)

6

Where do we find magnocellular neurons? What do they do?

Paraventricular and supraoptic nuclei; make oxytocin and vasopression and project directly to the posterior pituitary

7

Where do we find parvocellular neurons? What do they do?

Paraventricular nucleus; make "releasing factors" to influence the anterior pituitary: CRF, TRF, GnRF

8

Medial hypothalamus (feeding)

Satiety center (reduces feeding)

9

Lateral hypothalamus (feeding + 1 function)

Activates feeding and sleep-wakefulness (makes Orexin)

10

Ventromedial hypothalamus (feeding + 2 functions)

Reduces feeding; thermoregulation and sexual functions

11

Mammillary nuclei

Memory

12

What is the sole source of histamine in the brain?

Tuberomammillary nucleus

13

Most important brain inputs from cortex to hypothalamus (2)

Inhibitory from hippocampus and excitatory from amygdala

14

ANS inputs to hypothalamus (2)

Nucleus of the solitary tract and reticular formation

15

ANS outputs from hypothalamus

Medulla (parasymp = vagal nuclei) and spinal cord (preganglionic sympa = intermediolateral nucleus)

16

Suprachiasmatic nucleus is innervated by the...where does it send output? Then where? What does light do?

Optic nerve; superior cervical ganglion (sympa); activates pineal gland to release melatonin; TURNS OFF melatonin synthesis

17

All of the neuroendocrine and pre-autonomic neurons of the hypothalamus are innervated by what nucleus?

SCN

18

T/F: The molecular circadian clock is only located in the SCN

False: these molecules are present all over the body, it is just controlled by light in the SCN (hence, circdian rhythms)

19

Orexin is expressed solely in the...promotes...is also...

Lateral hypothalamus; wakefulness, arousal, reward; pro-feeding

20

Name two TF and one gene that regulates our circadian rhythms and describe

TF: Clock+Bmal and Period; Period inhibits Clock+Bmal and then neg feedbacks to inhibit itself; Period protein is degraded w/ a 24 hour cycle

21

Sleep appears to be essential for...

Memory consolidation

22

Sleep is thought to be initiated by...NT? Turns off (nuclei)?

Ventrolateral preoptic area (GABA); orexin (LH) and histamine (TMN)

23

Orexin and histamine usually project to...What do these usually do? Then what?

Monoamine and cholinergic nerve cells that provide major activation to thalamus; intrinsic circuits = large waves

24

Describe REM (NT?) and what turns this on? NT? Why does this not happen during the day?

Series of brainstem cholinergic cells (REM-on) become activated and trigger sensory input into thalamus (REM waves); LOSS of REM-off cells (monoamine); REM-off cells are normally activated by Orexin

25

What chemical builds during wakefulness that might trigger the VLPO?

Adenosine

26

Describe relationship between thermoregulation and sleep

Body cools at night and heats during the day; VLPO is involved in thermoregulation --> warming VLPO induces NREM sleep

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