11 - Hypothalamo-adenohypophysial system. Hormones of the anterior pituitary (adenohypophysis). Physiological effects and control of secretion.

sections

hypothalamo-adenohypophysial system

hormones of anteriro pituitary

physiologic effects and control of secretion

hypothalamo-adenohypophysial system

• Hypothalamus works with the anterior pituitary of the pituitary gland to induce or inhibit a range of processes.

• The hypothalamus produces many Neurosecretion that are released next to the primary capillary plexus.

• The hormones enter the long portal system → target cells in the adenohypophysis.

• These hormones can either stimulate or inhibit the release of other hormones from the pituitary gland.

hormones of anterior pituitary

1. (hGH, or STH)- Human growth hormone which controls general body growth and regulates metabolism. Increased by sleep stress, starvation, somatosatin

2. (TSH)-Thyroid-stimulating hormone which controls secretion of thyroid gland. T3, T4

3. (FSH) -Follicle-stimulating hormone which stimulates sperm production from Sertoli by the testes and the production of oocytes and estrogens by the ovaries.

4. (LH) -Luteinizing hormone which stimulates secretion of testosterone by the Leydig cells in the testes, secretion of estrogens and progesterone by the ovaries, and ovulation

5. (PrL)- Prolactin which together with other hormones, initiates and maintains milk production in the mammary glands. – works with estrogen, prolactin inhibits ovulation- by reducing estrogen and progesterone levels—prolactin inhibits itelf and dopamine inhibits prolactin--- pregnancy increasex and reastfeeding

6. (ACTH)- Adrenocorticotropic hormone which stimulates the adrenal cortex (outer region) to secrete its hormones. Stimulates lipolysis and gluconeogenesis

7. (MSH)- Melanocyte-stimulating hormone which affects skin pigmentation.

physiologic effects and control of secretion

what is hyperplasia and hypotrophy?

• hyperplasia - enlargement of organ or time due to an increase in rate of reproduction of its cell

• Hypotrophy - increase in volume of organ or tissue due to enlargement of its component cells

tropic hormones

Overall hormones secrete by the adenohypophysis are trophic hormones. Trophic hormones directly affect growth by hyperplasia or hypertrophy.

Tropic hormones are named after their ability to directly act upon their target cells/ tissue or endocrine glands, stimulating the release of other hormones