Histology
of
Pituitary
Gland
Introduction
to
the
Pituitary
• Also
called
hypophysis
• Consists
of
a
glandular
component
and
nervous
component
• Sits
at
the
base
of
the
skull
within
the
sella
turcica
of
the
sphenoid
bone
• Sits
in
the
hypophyseal
fossa
that
lodges
the
gland.
• Contains
the
anterior
(adenohypophysis)
and
posterior
(neurohypophysis)
portions.
• Adenohypophysis:
o Is
the
o Arises
as
an
epithelial
upgrowth
of
the
oral
cavity
(Rathke’s
pouch)
(Derived
from
oral
ectoderm)
o Contains
three
portions:
§ Pars
distalis
(anterior
lobe)
§ Pars
intermedia
§ Pars
tuberalis
o Cell
types
are
classified
as
chromophils
/
chromophobes
o Chromophiles:
§ Acidophils
• Somatotrophs
• Lactotrophs
/
mammotrophs
§ Basophils
• Thyrotrophs
• Gonadotrophs
• Corticotrophs
o Chromophobes
§ Little
/
no
affinity
for
stained
(paler)
§ Represent
stromal
cells
(connective
tissue),
degranulated
chromophil
cells,
or
undifferentiated
cells.
§ Cytoplasm
is
not
stained
but
you
can
see
a
nucleus.
, • Neurohypophysis
o Derived
from
neural
ectoderm
from
the
hypothalamus
(the
downgrowth
of
diencephalon)
o Remains
joined
to
the
hypothalamus
through
the
infundibular
stalk
o Includes
the:
§ Infundibulum:
median
eminence
+
infundibular
stalk
§ Pars
nervosa
• Pituitary
gland
lies
outside
the
blood
–
brain
barrier
• Some
sections
will
not
include
all
the
components
of
the
entire
gland
Posterior
pituitary
(neurohypophysis)
• Pars
nervosa:
o Biggest
part
of
the
posterior
pituitary.
Thus
called
the
posterior
lobe
of
the
pituitary
gland.
o Pale
stained
neural
tissue
o Vascular
connections
cannot
be
traced,
they
are
less
condensed
than
the
infundibular
stalk
and
the
median
eminence.
o Nuclei:
§ Round
/
oval,
large
:
pituicytes
§ Elongated
endothelial:
fenestrated
capillaries
§ Bright
pink
nuclei
:
non-‐neuronal
cells
o May
contain
HERRING
BODIES
–
faint
PAS+
where
unsecreted
ADH
and
oxytocin
are
degraded
by
lysosomes
along
with
their
carrier
proteins.
o Cannot
really
trace
the
axon
but
you
can
see
the
sinusoids.
o Carrier
proteins
of
the
hormones
are
called
neurophysins:
§ Stain
blue
–
black
with
CHROME
ALUMHEMATOXYLIN
of
Pituitary
Gland
Introduction
to
the
Pituitary
• Also
called
hypophysis
• Consists
of
a
glandular
component
and
nervous
component
• Sits
at
the
base
of
the
skull
within
the
sella
turcica
of
the
sphenoid
bone
• Sits
in
the
hypophyseal
fossa
that
lodges
the
gland.
• Contains
the
anterior
(adenohypophysis)
and
posterior
(neurohypophysis)
portions.
• Adenohypophysis:
o Is
the
o Arises
as
an
epithelial
upgrowth
of
the
oral
cavity
(Rathke’s
pouch)
(Derived
from
oral
ectoderm)
o Contains
three
portions:
§ Pars
distalis
(anterior
lobe)
§ Pars
intermedia
§ Pars
tuberalis
o Cell
types
are
classified
as
chromophils
/
chromophobes
o Chromophiles:
§ Acidophils
• Somatotrophs
• Lactotrophs
/
mammotrophs
§ Basophils
• Thyrotrophs
• Gonadotrophs
• Corticotrophs
o Chromophobes
§ Little
/
no
affinity
for
stained
(paler)
§ Represent
stromal
cells
(connective
tissue),
degranulated
chromophil
cells,
or
undifferentiated
cells.
§ Cytoplasm
is
not
stained
but
you
can
see
a
nucleus.
, • Neurohypophysis
o Derived
from
neural
ectoderm
from
the
hypothalamus
(the
downgrowth
of
diencephalon)
o Remains
joined
to
the
hypothalamus
through
the
infundibular
stalk
o Includes
the:
§ Infundibulum:
median
eminence
+
infundibular
stalk
§ Pars
nervosa
• Pituitary
gland
lies
outside
the
blood
–
brain
barrier
• Some
sections
will
not
include
all
the
components
of
the
entire
gland
Posterior
pituitary
(neurohypophysis)
• Pars
nervosa:
o Biggest
part
of
the
posterior
pituitary.
Thus
called
the
posterior
lobe
of
the
pituitary
gland.
o Pale
stained
neural
tissue
o Vascular
connections
cannot
be
traced,
they
are
less
condensed
than
the
infundibular
stalk
and
the
median
eminence.
o Nuclei:
§ Round
/
oval,
large
:
pituicytes
§ Elongated
endothelial:
fenestrated
capillaries
§ Bright
pink
nuclei
:
non-‐neuronal
cells
o May
contain
HERRING
BODIES
–
faint
PAS+
where
unsecreted
ADH
and
oxytocin
are
degraded
by
lysosomes
along
with
their
carrier
proteins.
o Cannot
really
trace
the
axon
but
you
can
see
the
sinusoids.
o Carrier
proteins
of
the
hormones
are
called
neurophysins:
§ Stain
blue
–
black
with
CHROME
ALUMHEMATOXYLIN
