Endocrine system part 2

the actions of some hormones on target cells require a simultaneous or recent exposure to a second hormone.  The second hormone is said to have this effect.

when the effect of two hormones acting together is greater or more extensive than the effect of each on its own, the two hormones have this effect.

when one hormone opposes the actions of another hormone.

is regulated by 1) signals from the nervous system 2) chemical changes in the blood 3) other hormones

secretes several hormones that control endocrine glands

controls the pituitary gland.  It is the major link between the nervous system and the endocrine system

the stalk that attaches the pituitary gland to the hypothalamus

accounts for 75% of the total weight of the gland.  It secretes hormones that regulate a wide range of bodily activities from growth to reproduction

stimulate the release of anterior pituitary hormones

suppresses the release of pituitary gland hormones.  Produced by the hypothalamus

blood flows from capillaries in the hypothalamus into the portal veins that carry blood to capillaries of the anterior pituitary gland.

clusters of specialized neurons.  They synthesize the hypothalamic inhibiting and releasing hormones in their cell bodies and package the hormones inside vesicles which are eventually released into the Hypophyseal portal system

released by the anterior pituitary gland.  It is secrete by somatotropins

A hypothalamic hormone which promotes secretion of human growth hormone

suppresses the secretion of human growth hormone

stimulates the synthesis and secretion of the two thyroid hormones T3 and T4, both produced by the thyroid gland. Produced by the anterior pituitary gland

from the hypothalamus controls TSH secretion. Release of it depends on blood levels of T3 and T4

target the ovaries.  It initiates the development of several ovarian follicles.  It also stimulates follicular cells to secrete estrogen and sperm in males. Produced by the anterior pituitary gland

released from the hypothalamus and stimulates FSH and LH release

triggers ovulation in females and the secretion of estrogen. In males it stimulates the testes to secrete testosterone. Produced by the anterior pituitary gland

initiates and maintains milk secretion by the mammary glands, only after mammary glands have been prepared by other hormones does it bring about the secretion of milk. Produced by the anterior pituitary gland

produced by the hypothalamus, they regulate PRL secretion.  In females it is dopamine.  Just before menstruation this hormone diminishes.

the sucking action of nursing infants causes a reduction of hypothalamic secretion of PIH

these are secreted by corticotrophs.  This hormone controls the production and secretion of cortisol and other glucocoticords by the cortex of the adrenal gland

from the hypothalamus.  Stimulates the secretion of ACTH by corticotrophs.  stress related stilmuli, such as low blood glucose or physical trauma also stimulate the release of ACTH

increases skin pigmentation in apmphibians.  Not sure why it is present or what it does in humans. Produced by the anterior pituitary gland