The pars nervosa of the posterior pituitary consists of
modified neural tissues containing unmyelinated axons
supported and ensheathed by glia cells called pituicytes
(P), the most numerous cell present. The axons run from
the supraoptic and paraventricular hypothalamic nuclei, and
have swellings called neurosecretory (Herring) bodies (NB)
from which either oxytocin or vasopressin is released upon
neural stimulation. The released hormones are picked up by
capillaries (C) for distribution. X400. H&E.