Bsf Exam 4: Hypothalamic/pituitary Axis

Front 1

Which lobe of the pituitary is made of neural tissue?

Back 1

posterior pituitary

Front 2

Which lobe of the pituitary is a true endocrine gland?

Back 2

anterior pituitary

Front 3

The posterior pituitary lobe has innervation from the hypothalamus through what 2 nuclei?

Back 3

1. paraventricular
2. supraoptic

Front 4

What 2 neurohormones are produced by the posterior pituitary? What class of hormones are these?

Back 4

oxytocin and vasopressin (also called antidiuretic hormone or ADH). Both are peptides

Front 5

When is ADH released?

Back 5

Released when osmoreceptors in the hypothalamus detect an INCREASE IN PLASMA OSMOLARITY (you have high plasma osmolarity, so the body's homeostatic response will want to dilute the plasma).
or decreased BP (decreased extracellular volume)

Front 6

What does the neurohormone ADH do?

Back 6

Induces greater retention of water in the body, thereby decreasing plasma osmolarity

Front 7

What does the neurohormone oxytocin do?

Back 7

induces milk let-down during lactation and uterus contraction during labor

Front 8

What are the 6 hormones released by the anterior pituitary?

Back 8

1. Prolactin
2. TSH: thyroid stimulating hormone
3. ACTH: adrenocorticotropic hormone
4. GH: growth hormone
5. FSH: follicle stimulating hormone
6. Lutenizing hormone

*Remember, the anterior pituitary is true endocrine tissue (posterior is neural)

Front 9

What are trophic hormones? Of the 6 anterior pituitary hormones, which ones are trophic hormones?

Back 9

-Trophic hormones are hormones that regulate ANOTHER gland/cell
-Every hormone secreted by the anterior pitutiary is a trophic hormone EXCEPT FOR PROLACTIN

Front 10

What is a releasing hormone?

Back 10

A releasing hormone regulates the anterior pitutiary hormones (*that makes releasing hormones trophic hormones. Remember, 5 of the 6 anterior pituitary hormones are also trophic hormones, but ALL RELEASING HORMONES are also considered trophic hormones).

Front 11

Where are the 3 portal systems located in the body?

Back 11

1. Kidney
2. Digestive-liver system
3. Hypothalamic-hypophyseal portal system

Front 12

Describe trophic releasing hormone secretion and ultimate function in relation to the portal system.

Back 12

Trophic releasing hormones from hypothalamus are secreted into first capillary bed and travel to 2nd capillary bed via portal vessel connection. The trophic releasing hormones then diffuse out and bind to endocrine cells, which then secrete hormones (i.e., the 6 anterior pituitary hormones).

Front 13

What is the advantage of having a trophic portal system?

Back 13

A very small amount of trophic releasing hormones is needed since they are confined to the portal system and are not released into general circulation.

Front 14

What is the difference between long loop and short loop negative feedback?

Back 14

Front 15

Caesin and lactalbumin are milk proteins that are secreted due to the action of what hormone?

Back 15

Prolactin

Front 16

In addition to secreting milk proteins, what else does prolactin do?

Back 16

-inhibits LH (luteinizing hormone) and FSH (follice stimulating hormone) secretion via hypothalamic GnRH (gonadotropin releasing hormone) suppression

-stimulates additional mammary growth (SWEEEET!!)

Front 17

How does the hypothalamus regulate the release of prolactin?

Back 17

-Prolactin releasing factor (PRF) stimulates
-Dopamine inhibits

Front 18

What does thyroid stimulating hormone do?

Back 18

Stimulates thyroid to release T3 and T4, which regulate metabolism in most tissues

Front 19

How does the hypothalamus regulate thyroid stimulating hormone?

Back 19

thyrotropin releasing hormone (TRH)

Front 20

What does adrenocorticotropic (ACTH) hormone do?

Back 20

stimulates adrenal cortex to release cortisol, which regulates metabolism under stress

Front 21

How does the hypothalamus regulate adrenocorticotropic hormone?

Back 21

corticotropin releasing hormone (CRH)

Front 22

What does growth hormone (GH) do?

Back 22

stimulates liver to release insulin-like growth factors (IGFs) to regulate growth and metabolism

Front 23

How does the hypothalamus regulate growth hormone?

Back 23

-growth hormone releasing hormone (GHRH)
-somatostatin (inhibits GH release from anterior pituitary)

Front 24

What does follicle stimulating hormone (FSH) do?

Back 24

stimulates androgen production in testes and estrogen/progesterone production in ovaries--important in reproduction

Front 25

How does the hypothalamus regulate follicle stimulating hormone?

Back 25

gonadotropin releasing hormone (GnRH)