the pituitary gland has two lobes an anterior and a posterior in this section we're going to
talk about the posterior pituitary gland it's also known as the neuro hypothesis sometimes
the pituitary gland as a whole is referred to as the hypothesis so the posterior pituitary gland
is this section here the posterior pituitary gland is a direct extension of the hypothalamus in the
brain it has there are two nuclei within the hypothalamus that secrete their hormones into
the posterior pituitary and these are the super optic nucleus or SONin and the para ventricular
nucleus or the pvn so SON, PVN Supra optic and para ventricular secrete their hormones into the
posterior pituitary gland they're made up of let me electron to so there are their neural
endocrine cells or neurosecretory cells so these are really special neurons there they
look like neurons and they act like neurons to a large degree but instead of synapsing
with another neuron their axon terminals here in the posterior pituitary release hormones
and the two hormones they release our oxytocin and vasopressin and we'll talk a little bit
more about those in detail in the future in the next couple of slides but super optic
nucleus and the paraventricular nucleus here kind of here and here are made of or contain
neurosecretory cells and neurosecretory cells are neurons but they instead of synapsing on
another neuron they're simply going when they're activated and they send an action potential down
their axons it's going to result instead of the release of a neurotransmitter it's going
to result in the release of a neural hormone and that neural hormone is then going to be
released into the vascular bed of the posterior pituitary gland the two hormones that are made
by the neurons of by the neurons of the sonf pbn are oxytocin and vasopressin vasopressin
is also known as anti diuretic hormone or ADH so oxytocin secreted into the posterior
pituitary gland has effects on both the uterus and the breast or the mammary gland so during
childbirth oxytocin increases the contractility of the uterus to facilitate birth and during
lactation and during nursing oxytocin causes the release of milk for the suckling infant
vasopressin acts on the kidney vasopressin or antidiuretic hormone diuresis is losing fluid and
that's of course what your kidneys do is help you regulate your fluent fluid balance so vasopressin
acts on the kidney to increase water absorption so anti diet rhesus antidiuretic hormone it also
acts on your sweat glands to decrease sweating it inhibits sweating and it contributes to
constricting your arterioles so vasopressin is another way of thinking of increasing your blood
pressure so oxytocin acts on on the breast or mammillary gland and the uterus vasopressin or
antidiuretic hormone acts on the kidney and both of these hormones are made in the s the
super optic nucleus the paraventricular nucleus both are released into the posterior pituitary
capillary beds in the next section we'll talk about the anterior pituitary how the hypothalamus
regulates it and then what the anterior pituitary how it regulates the rest of your endocrine system