Hypothalamus

Question 1

Hypothalamus synthesizes at least _____ different hormones

Answer 1

9

Question 2

Pituitary gland secretes ______ hormones

Answer 2

7

Question 3

Hormones of the hypothalamus + Hormones of the pituitary =

Answer 3

regulation of all aspects of growth, development, metabolism & homeostasis.

Question 4

Non-endocrine functions of the hypothalamus

Answer 4

• temperature regulation
• activity of the autonomic nervous system
• control of appetite

Question 5

Hypothalamic hormones are small peptides that…

Answer 5

are active only at high concentrations achieved in the pituitary portal blood system, but are rapidly degraded & have low concentration levels in the peripheral circulation. This is due to their small size & lack of known binding proteins.

Question 6

Anatomy of the hypothalamus

Answer 6

• located at the base of the brain, below the 3rd ventricle & above the optic chiasm & pituitary gland.

Question 7

Terminals of the hypothalamic neurons are in the _____ _____, where hormones are released directly into a primary capillary plexus.

Answer 7

median eminence

Question 8

Special circulation of the hypothalamic hormones

Answer 8

(1) Terminals of the hypothalamic neurons are in the median eminence, where hormones are released directly into a primary capillary plexus.
(2) The capillaries empty into the portal venous circulation —- travel down the pituitary stalk —- & bathe the anterior pituitary gland in a secondary capillary plexus.
(3) Thus, the hormones released by the hypothalamic neurons reach their target cells rapidly & in high concentrations before being diluted in peripheral blood.

Question 9

Why is the special circulation (close proximity) for hypothalamic hormones crucial?

Answer 9

For the preservation of the pulsatile output of hormones from the hypothalamic neurons.

Question 10

2 types of hormones released by the hypothalamus

Answer 10

1. Releasing hormones
2. Inhibiting hormones

Question 11

Releasing hormones (5)

Answer 11

• Gonadotropin-releasing hormone (GnRH)
• Thyrotropin-releasing hormone (TRH)
• Prolactin-releasing hormone (PRH)
• Adrenocorticotropin-releasing hormone (ACTH)
• Growth hormone-releasing hormone (GHrH)

Question 12

Inhibiting hormones (2)

Answer 12

• Prolactin-inhibiting hormone (PIH) / Dopamine
• Growth-inhibiting hormone (GHIH) / Somatostatin

Question 13

Other hormones (stored in the posterior pituitary gland) - 2

Answer 13

• Oxytocin
• Antidiuretic hormone (ADH)

Question 14

Hormones that are dependent on blood levels

Answer 14

• Gonadotropin-releasing hormone (GnRH)
• Thyrotropin-releasing hormone (TRH)
• Adrenocorticotropin-releasing hormone