Pituitary Gland
The pituitary gland is about the size of a pea, situated almost ex-
actly in the center of the head at the base of the brain and just
behind the root of the nose. It hangs suspended from the under-
side of the brain like a cherry from the limb of a tree. It is grayish
yellow in color. In the adult it weighs about five grains, or 1/1400 of
a pound.
Its name is derived from the Latin word, “pituita”, because it
was supposed to secret a fluid which lubricated the throat. It was
believed that the secretion filtered through the porous ethnoid bone
that intervenes between the pituitary body and the nasal cavity.
Tongue Touches The Palate..............................................
Embryologically, the pituitary begins by manifesting as an out-
growth of the mouth cavity. This outgrowth takes the form of a
pouch, which gradually extends toward the brain. By the end of the
fourth week this protrusion contacts a downgrowth from the brain
called the infundibulum. The pouch then develops into the anterior
lobe of the pituitary, whereas the infundibulum, representing an
outgrowth of the oldest part of the nervous system, develops into
the posterior lobe of the gland. There is a space between the walls
of the anterior and posterior parts of the gland, which persists
throughout life as the cleft of the gland. The pituitary gland is di-
vided into an anterior or front portion, which is composed of glan-
dular tissue and a posterior or back portion, which is composed of
nerve-like tissue. The anterior portion produces several hormones
which stimulate distant structures such as: a growth hormone, a
hormone which stimulates the adrenal cortex, a thyroid stimulating
hormone and also a hormone which stimulates breast milk pro-
duction and another which influences pigment production by cer-
tain cells of the skin.
The posterior part of the gland is an extension of the hypothala-
mus, that portion of the brain to which the pituitary is attached.
The posterior lobe of the pituitary body secretes several impor-
tant hormones, two of which deserve special attention. One of them,
called pitocin, has a powerful stimulating effect on the pregnant