Hypothalamus

Question 1

Define and give the function of neurophysin

Answer 1

Carrier protein that facilitates the transport of oxytocin and ADH (anti-diuretic hormone or vasopressin) from the hypothalamus to the neurohypophysis (posterior pituitary)

Question 2

List the factors that stimulate oxytocin secretion, and describe where and how they act

Answer 2

Stimulation of mammary glands by suckling causes neuroendocrine cells to synthesize oxytocin, which is stored in the neurohypophysis until the nerve is stimulated, releasing oxytocin into capillaries, where it flows into the blood and stimulates contraction of the myoepithelial cells for milk letdown
Oxytocin also causes contraction of uterine smooth muscle for expulsion of the fetus at parturition (birth)

Question 3

List the major clinical uses of oxytocin

Answer 3

Pitocin (oxytocin analogue with a longer half-life) is used to facilitate parturition or milk letdown

Question 4

Describe the site of action of vasopressin (ADH)

Answer 4

acts on the kidney tubules, arterioles, sweat glands (all constricted)

Question 5

List by name and abbreviation the hypothalamic releasing and inhibiting hormones along with their major actions

Answer 5

GHRH: Growth Hormone Releasing Hormone- acts on somatotrophs, stimulates the adenohypophysis (anterior pituitary) release of GH (growth hormone)
GHIH/GIH: Growth Hormone Inhibiting Hormone (somatostatin)- acts on somatotrophs, inhibits production of GH by the adenohypophysis (anterior pituitary)
GnRH: Gonadotropin Releasing Hormone- acts on lutetropes and folliculotropes to stimulate adenohypophysis production of Follicle Stimulating Hormone (FSH) and Luteinizing Hormone (LH)
TRH: Thyrotropin Releasing Hormone- acts on thyrotrophs of the adenohypophysis to stimulate Thyroid Stimulating Hormone (TSH)
CRH: Corticotropin Releasing Hormone- acts on corticotropins to stimulate adenohypophysis production of Adrenocorticotropic Hormone (ACTH)
Dopamine: Prolactin inhibiting factor- inhibits adenohypophysis production of prolactin
PRF: Prolactin Releasing Factor- stimulates adenohypophysis production of prolactin

Question 6

Define: Hypothalamus

Answer 6

site of Hormone production, has neuroendocrine cells with axons that project through the stalk and into the posterior pituitary

Question 7

Define: Neurohypophysis

Answer 7

posterior pituitary; composed of neural tissue, secretes (does not synthesize) Oxytocin and ADH; site of hormone storage and release

Question 8

Define: Adenohypophysis

Answer 8

anterior pituitary; consists of pars distalis, pars intermedia, and pars tuberalis; produces protein/peptide hormones

Question 9

Define: Portal vessels

Answer 9

transport neurohormones from hypothalamus to posterior pituitary

Question 10

Define: Neuroendocrine

Answer 10

cells within hypothalamus which release neurohormones to regulate the anterior pituitary, Cell bodies are in hypothalamus, but axons terminate in posterior pituitary

Question 11

Define: Oxytocin

Answer 11

secreted by neurohypohysis, stimulates smooth muscle contraction of the uterus(contractions) and mammary glands (milk let down), Works with estrogen and is inhibited by progesterone

Question 12

Define: Lactation

Answer 12

Milk Production

Question 13

Define: Diabetes insipidus

Answer 13

hyposecretion (most common) or lack of responsiveness to ADH. Excessive urination, dehydration, thirst.

Question 14

Explain how prolactin and oxytocin affect milk letdown

Answer 14

prolactin actually regulates milk production, when oxytocin is stimulated, it contracts the myoepithelium cells of the mammary gland, causing milk letdown

Question 15

Define: Granules

Answer 15

contain neurohypophysial hormones

Question 16

Name and give the function of TRH

Answer 16

Thyrotropin Releasing Hormone- acts on thyrotrophs of the adenohypophysis to stimulate Thyroid Stimulating Hormone (TSH)

Question 17

Name and give the function of CRH

Answer 17

Corticotropin Releasing Hormone- acts on corticotropins to stimulate adenohypophysis production of Adrenocorticotropic Hormone (ACTH)

Question 18

Name and give the function of GH

Answer 18

Growth hormone, secreted by the adenohypophysis, has effects on protein, glucose and lipid metabolism; stimulated by GHRH and inhibited by GHIH (hypothalamic hormones)

Question 19

Name and give the function of LH

Answer 19

Luteinizing hormone, produced by the adenohypophysis, stimulates Leydig cells to produce testosterone (males); production is stimulated by GnRH (hypothalamic hormone)

Question 20

Name and give the function of FSH

Answer 20

Follicle Stimulating Hormone, produced by the adenohypophysis, acts on Sertolli cells to produce sperm (males); production is stimulated by GnRH (hypothalamic hormone)

Question 21

Name and give the function of ACTH

Answer 21

Adrenocorticotropic Hormone; produced by the adenohypophysis, production stimulated by Corticotropin Releasing Hormone; acts on the adrenal glands to stimulate cortisol production

Question 22

Name and give the function of TSH

Answer 22

Thyroid Stimulating Hormone; produced by the adenohypophysis, production stimulated by Thyrotropin Releasing Hormone; acts on the thyroid gland to produce T4 and T3

Question 23

Name and give the function of GnRH

Answer 23

Gonadotropin Releasing Hormone- acts on lutetropes and folliculotropes to stimulate adenohypophysis production of Follicle Stimulating Hormone (FSH) and Luteinizing Hormone (LH)

Question 24

Name and give the function of ADH

Answer 24

Anti-diuretic hormone (vasopressin); creating in the hypothalamus and transported/stored in the neurohypophysis; acts on the kidney tubules, arterioles, sweat glands, functions in water retention