Lecture 25: Hypothalamus

Question 1

Main function of the hypothalamus

Answer 1

Homeostasis

Question 2

What part of the embryonic brain does the hypothalamus come from?

Answer 2

Diencephalon

Question 3

Where is the hypothalamus located in the brain?

Answer 3

Question 4

Specific functions of the hypothalamus (6)

Answer 4

1. Controls release of 8 major hormones via hypophysis
2. Temperature regulation
3. Control of food and water intake
4. Sexual behavior and reproduction
5. Daily control of state and behavior
6. Mediation of emotion

Question 5

Inputs to the hypothalamus (6)

Answer 5

1. Nucleus of the solitary tract
2. Reticular formation
3. Retina
4. Circumventricular Organs
5. Limbic and olfactory systems
6. Thermo- and osmoreceptors (intrinsic)

Question 6

How does the nucleus of the solitary tract interact with the hypothalamus?

Answer 6

Collects visceral info like blood pressure and gut distension from vagus; gives info to hypothalamus

Question 7

How does the reticular formation interact with the hypothalamus?

Answer 7

Reticular areas receive info from spinal cord like skin temp which goes to hypothalamus

Question 8

How does the retina interact with the hypothalamus?

Answer 8

Some fibers in the retina go to the suprachiasmatic nucleus in the hypothalamus which regulates ciradian rhythms

Question 9

How do circumventricular organs interact with the hypothalamus?

Answer 9

No blood brain barrier so these parts of the brain sample the blood for things like osmolarity and toxins

OVLT, supraoptic crest, area postrema

Question 10

How do the limbic and olfactory systems interact with the hypothalamus?

Answer 10

Help regulate behavior like eating and reproduction

Question 11

Two ways that the hypothalamus helps fix problems

Answer 11

1. Neural signals to autonomic system; medulla and spinal cord
2. Endocrine signals to pituitary which releases releasing factors or oxytocin/vasopressin

Question 12

What is significant about the supraoptic and paraventricular regions of the hypothalamus?

Answer 12

Cells there release oxytocin, ADH, and CRH

Question 13

What is the main job of the suprachiasmatic nucleus?

Answer 13

• Regulates circadian rhythm via light input from retina
• Turns off the paraventricular nuclei cells that project to pineal gland where melatonin is released
• Activity produced here that increases sweating, vasodilation, panting
  
  • Lesion leads to hyperthermia

Question 14

What areas does the tuberal region of the hypothalamus contain?

Answer 14

1. Ventromedial nucleus
2. Arcuate nucleus
3. Lateral hypothalamic area

Question 15

What is significant about the fornix in the hypothalamus?

Answer 15

It divides the lateral from the medial portion

Question 16

Arcuate nucleus

Answer 16

• Neurons that control endocrine functions of adenohypophysis
• Secrete release or release-inhibiting factors

Question 17

Ventromedial nucleus of hypothalamus

Answer 17

• Control of eating
• Satiety
• Lesions
  
  • Obesity
  • Rage

Question 18

Ventrolateral hypothalamic area

Answer 18

• Promotes eating
• Increase in apetite
• Orexin neurons that stabilize wakefulness
• Lesion
  
  • Anorexia
  • Sometimes death by starvation
  • Narcolepsy

Question 19

Parts in the mammillary region of the hypothalamus

Answer 19

1. Posterior hypothalamic nucleus
2. Mammillary nuclei

Question 20

Posterior hypothalamic nucleus

Answer 20

• Thermoregulation
• Vasoconstriction, piloerection, and shivering
• Lesion
  
  • Hypothermia

Question 21

Mammillary bodies

Answer 21

Associated with memory

Question 22

Summary chart of hypothalamus functions (picture)

Answer 22