The Hypothalamus

Question 1

The hypothalamus is made up of distinct nuclei (collections of cell bodies) that include the supraoptic, paraventricular (PVN), suprachiasmatic, ventromedial, dorsomedial, and arcuate nuclei. What do the neurons secret that control the synthesis and secretion of the anterior pituitary hormones.

Answer 1

Neurohormones

Question 2

The nomenclature of these neurohormones describes their actions and can be subdivided into

Answer 2

‘releasing’ and ‘inhibiting’ hormones

Question 3

The axons of these neurons all converge in the median eminence to deposit their endocrine products into the capillary plexus that empties into the portal blood vessels of the anterior pituitary permitting hypothalamic neurohormone delivery in a

Answer 3

rapid concentrated fashion to the anterior pituitary.

Question 4

The neurohormone gonadotropin-releasing hormone (GnRH) stimulates the

Answer 4

anterior pituitary to release FSH and LH and is thus involved in folliculogenesis.

Question 5

The preoptic area (POA) of the hypothalamus contains many GnRH neurons that

Answer 5

project (along with the GnRH neurons in the ARC) to the median eminence.

Question 6

Which neuropeptide influences GnRH secretion?

Answer 6

Kisspeptin

Question 7

What is the kisspeptin system critical for?

Answer 7

Maturation and function of the reproductive axis including the onset of puberty.

Question 8

Kisspeptin neurons (whose cell bodies reside in the ARC and rostral hypothalamus) interact with

Answer 8

GnRH neurons influencing GnRH secretion by several different mechanisms.

Question 9

There is evidence that hypothalamic kisspeptin also mediates

Answer 9

sex-steroid feedback and metabolic input on the reproductive axis.

Question 10

Other active factors exert important actions at the level of the anterior pituitary. Thus, the specific protein hormone-secreting endocrine cells of the anterior pituitary must process signals not only from the hypothalamic hormone(s) but also additional centrally derived factors that are secreted into

Answer 10

the hypophyseal portal blood.