Page 54 - The Miracle of Hormones

THE MIRACLE OF HORMONES

Hypothalamus
ADH and oxytocin
are produced in
neurosecretory
cells in the When the level of fluid in the
hypothalamus
blood falls, a message comes to
the hypothalamus. As a result of
this, nerve cells in the hypothal-
amus send a message for ADH
to be secreted. The ADH hor-
mone ensures that more fluid
will be absorbed back from the
kidneys. After the blood is di-
When appropriate, luted, the secretion of ADH
ADH and oxytocin stops.
are secreted from
axon endings into
Posterior pituitary
the bloodstream

Anterior pituitary

stimulus
Artery

sensor
negative concentrated
ADH feedback blood
hypothalamus
normalcy

dilute blood

posterior pituitary

response

ADH
kidney
tubules kidney tubules