Hypothalamus

Question 1

Medial pre optic area

Answer 1

This is a diffuse region anteriorly that is important for temperature regulation, water balance as well as neurosecretion.

Question 2

Suprachiasmatic nucleus

Answer 2

This nucleus is the master clock for circadian rhythms in sleeping and waking, body temperature, hormone secretion, and other physiological variables. The retina directly projects to this nucleus via collaterals of the optic nerve.

Question 3

Arcuate (infundibular) nucleus

Answer 3

Located directly above the median eminence. Controls numerous physiological functions with at least 15 subtype of neurons. Estrogen feedback, growth hormone, leptin receptors, control body weight…etc.

Question 4

Paraventricular nucleus

Answer 4

Has mangocellular neurons that project to the posterior pituitary gland and secrete oxytocin and vasopressin. Small PVN neurons (parvocellular) neurons project to the brainstem to control multiple autonomic functions eg. food intake, blood pressure, cardiovascular function, etc. Also secrete CRH and TRH into the portal system.

Question 5

Supraoptic nuclei

Answer 5

Like the PVN, magnocellular neurons in the supraoptic nucleus project to the posterior pituitary and secrete oxytocin and vasopressin into the portal plexus and hence systemic circulation.

Question 6

Dorsal Longitudinal Fasciculus

Answer 6

Periventricular tract (right next to the ventricle) interconnecting the hypothalamus to autonomic nuclei in the brainstem. It also has rostral projections.

Question 7

Medial forebrain bundle

Answer 7

A complex collection of fibers traveling through the lateral hypothalamus. This tract consists of axons coursing rostral and caudally connecting the cerebral cortex with the brainstem and spinal cord.

Question 8

Fever occurs when warm-sensitive neurons are inhibited by __________.

Answer 8

Prostaglandins