2.2 - Hypothalamus and pituitary gland

How does the hypothalamus affect the anterior pituitary

secretes releasing factors to stimulate hormone secretion or inhibiting factors to do the opposite, they travel through the blood

how does the hypothalamus affect the posterior pituitary

produces hormones that pass along nerve fibers for the posterior pituitary to store and secrete

what joins the hypothalamus and the pituitary gland

the infundibulum

how are the anterior and posterior pituitary glands connected to the hypothalamus

anterior - blood vessel network in the infundibulum

posterior - nerve fibers that come from nerve cell bodies in hypothalamus and pass through infundibulum

why isnt the posterior pituitary a true gland

it doesnt secrete substances, it just stores and releases hormones

What are the six hormones secreted by the anterior pituitary

1. follicle stimulating hormone

2. luteinizing hormone

3. growth hormone

4. thyroid stimulating hormone

5. prolactin

6. adrenocorticotropic hormone

follicle stimulating hormone

targets ovaries for follicle development and testes for sperm production

lutenising hormone

targets ovaries for prompting ovulation and maintaining corpus luteum, targets testes for stimulating release of testosterone

growth hormone

targets whole body but particularly skeleton, increases rate at which amino acids are converted into proteins

thyroid stimulating hormone

targets thyroid gland, controls production and release of hormone thyroxine

adrenocorticotropic hormone

targets adrenal cortex, controls production and release of certain hormones

prolactin

targets breasts, stimulates and maintains milk production alongside other hormones

how do hypothalamus hormones get from the hypothalamus to the posterior pituitary

produced in special nerve cells in the hypothalamus

these cells have long extensions that pass through the infundibulum to the posterior pituitary

release triggered by nerve impulses initiated in hypothalamus

stored in posterior pituitary for later release into the blood stream

oxytocin

targets uterus and mammary glands, causes contractions in uterus in labour and releases milk when lactating

antidiuretic hormone

targets kidney nephrons, maintains concentration of water in the urine by changing the nephron walls permeabilty