25 Lecture Hypothalamus

Question 1

What is the developmental origin of the hypothalamus (brain primordia)

Answer 1

the diencephalon, along with the thalamus

Question 2

What are circumventricular organs?

Answer 2

places in the brain that contain fenestrated endothelial cells ie. pineal body, posterior pituitary, choroid plexus

Question 3

Where does the hypothalamus receive inputs from?

Answer 3

viscerosensory, internal receptors (circumventricular organs), retina, olfactory, amygdala, hippocampus

Question 4

What is the overarching function of the hypothalamus?

Answer 4

maintain homeostasis (has many nuclei with differing functions around homeostasis)

Question 5

What is the hypothalamus’ role in neural control?

Answer 5

considered the head ganglion of the autonomic nervous system

Question 6

What role does the hypothalamus play in regulation of the endocrine system?

Answer 6

hypothalamus feeds directly into posterior pituitary to release hormones, it works through the portal system of the anterior pituitary system which can release hormones into the systemic circulation

Question 7

How does the hypothalamus receive blood flow?

Answer 7

branches of the middle carotid arteries go to the hypothalamus

Question 8

Name the three general regions of the hypothalamus.

Answer 8

the supraoptic, tuberal and mammillary regions from cranial to caudal

Question 9

What are the four areas/ nuclei that are located in the supraoptic region?

Answer 9

paraventricular nucleus, suprachiasmatic nucleus and supraoptic nucleus along with the anterior region

Question 10

What occurs at the paraventicular nucleus?

Answer 10

neuroendocrine cells synthesize and secrete oxytocin and ADH directly into blood vessels CRH from the adenohypophysis causes release of cortisol from the adrenal cortex

Question 11

What occurs at the supraoptic nucleus?

Answer 11

neuroendocrine cells synthesize and secrete oxytocin and ADH,H from the adenohypophysis causes release of cortisol from the adrenal cortex

Question 12

How does cortisol release regulate coincide with natural rhythms?

Answer 12

cortisol increases energy supplies like increases blood sugar - supplies energy

Question 13

What role does the suprachiasmatic nucleus play in the internal clock?

Answer 13

the suprachiasmatic nucleus receives info from retinal ganglia that are light sensitive, giving information about day and night- helps to modulate the melatonin release from the pineal gland by inhibiting melatonin secretion

Question 14

What are the physiological consequences of melatonin?

Answer 14

increased melatonin levels cause drowsiness, lower body temperature

Question 15

What is the function of the anterior region?

Answer 15

thermoregulation via descending autonomics (panting, sweating and vasodilation

Question 16

What are the 3 nuclei/ areas in the tuberal region?

Answer 16

ventromedial nucleus, arcuate nucleus and lateral hypothalamic area

Question 17

What occurs in the arcuate nucleus?

Answer 17

arcuate nucleus releases hormones that cause the release or inhibit the release of hormones from the anterior pituitary gland (TRH, CRH, GnRH, GHRH and somatostatin are released)

Question 18

What is the main function of the ventromedial nucleus?

Answer 18

satiety center, legions can also cause rage-like outbursts

Question 19

How does leptin affect the hypothalamus?

Answer 19

leptin is secreted by adipocytes and binds to receptors in the ventro medial nucleus where they act to curb appetite

Question 20

What is the main function of the lateral hypothalamic area?

Answer 20

responsible for promoting appetite NOTE fornix runs through hypothalamus near the fornix, considered a dompaminergic highways which are important for the reward center

Question 21

What is the action of orexin/hypocretin?

Answer 21

an excitatory neuropeptide secreted in the lateral hypothalamus, increases arousal, energy and increases appetite (orexin receptors have been found to play a part in canine narcolepsy)

Question 22

What is the interplay between lateral hypothalamic area and ventral medial nuclei?

Answer 22

a dynamic exists between lateral hypothalamic area and ventro medial nucleus to establish a set point for body weight

Question 23

What is the action of the medial forebrain bundle?

Answer 23

motivates behaviors like feeding drinking and mating

Question 24

Name the two parts of the mammilary region.

Answer 24

posterior hypothalamus, mammillary bodies

Question 25

What is the function of the posterior hypothalamus?

Answer 25

poster hypothalamus promotes heat production via descending autonomic nervous system activating vasoconstriction, piloerection, and shivering

Question 26

What is Korsakoff’s psychosis?

Answer 26

a lesion on the mammilary body will lead to problems in memory, specifically remembering the timeline of events (is a encoding defect that can lead to confabulation to construct stories around incorrect timelines