Much of the above information is used by the hypothalamus to control secretions of the
pituitary hormones. The hypothalamus contains nuclei that synthesize and secrete hormones
(via neurons which extend and end) onto their target pituitary gland capillaries.
Hypothalamic supraoptic + paraventricular
nuclei synthesize and secrete ADH + Oxytocin
(via large, magnocellular neurons) directly into
POSTERIOR PITUITARY GLAND blood vessels.
Anotações:
Thus
posterior pituitary gland does not synthesize own hormones. They simply channel the ADH and Oxytocin produced by the Hypothalamus.
Other Hypothalamic nuclei synthesize and secrete Hypothalamic Releasing and Hypothalamic
Inhibitory hormones (or factors) into primary capillary plexus (median eminence - see
image) which then travel down, via Hypothalamic-hypophysial portal vessels, into
ANTERIOR PITUITARY GLAND,
and either stimulate or
inhibit their synthesis of
hormones
Also, almost all the blood that enters anterior pituitary first passes through the capillary
bed in the lower hypothalamus (median eminence - see "Artery" in image). The blood then flows
through the hypothalamic-hypophysial portal blood vessels into the anterior pituitary sinuses.
You can guess what they inhibit by their names:
Dopamine inhibits Prolactin.
Somatostatin inhibits Growth Hormone.
Receives signals from many sources in the nervous system. Thus, it is a
collecting center for information concerning the internal well-being of body.
Anotações:
Pain, depressing or exciting
thought, concentrations of nutrients, electrolytes, water, various hormones in the blood,
olfactory stimuli (transmit strong signal components directly and through the amygdaloid
nuclei) a portion of all these signals are transmitted into the hypothalamus.