This photomicrograph of the pars distalis is from an area where there is an almost equal distribution of acidophils (A) and basophils (B). The clumps and cords of cells are delineated by strands of connective tissue (stained blue) that surround them. A number of engorged capillaries (Cap) containing red blood cells (stained yellow) are also seen. The acidophil cytoplasm in this preparation
Pars nervosa, pituitary, human, H&E ×325.
The pars nervosa of neurohypophysis seen here contains cells called pituicytes, and unmyelinated nerve fibers form the supraoptic and paraventricular nuclei of the hypothalamus. The pituicytes (P) are comparable with neuroglial cells of the central nervous system. The nuclei are round to oval; the cyto plasm extends from the nuclear region of the cell as long processes. In H&E preparations such as this, the cytoplasm of the pituicyte cannot be stains a reddish or rust color. The basophils stain a reddish blue to deep blue, and the chromophobes (C ) exhibit a pale-blue color. The inset shows the three general cell types at higher magnification. The secretory granules of the acidophils (A) and basophils (B) are just discernable. It is the granules that stain and provide the overall coloration to the two cell types. In contrast, the chromophobe (C) lacks granules and simply reveals a pale-blue background color.
distinguished from the unmyelinated nerve fibers. The hormones of the neurohypophysis, oxytocin and antidiuretic hormone (ADH) (also called vasopressin), are formed in the hypothalamic nuclei and pass via the fibers of the hypothalamohypophyseal tract to the neurohypophysis, where they are stored in the expanded nerve terminal portion of the nerve fibers. The stored neurosecretory material appears as Herring bodies (HB). In H&E preparations, the Herring bodies simply appear as small islands of eosinstained substance. Interspersed among the nerve fibers are capillaries (Cap).
Pars nervosa, pituitary, human, PAS/aniline blue-black ×250; inset ×700.
In this specimen from pars nervosa, the aniline blue has stained the nuclei of the pituicytes (P); the nerve fibers have taken up some of the stain to give a light-blue background. With this staining technique, the Herring bodies (HB) appear as the dark black islands. The inset shows the Herring body near the bottom of the micrograph at high magnification. The granular texture of the Herring body as seen here is a reflection of the accumulated secretory granules in the nerve terminals. Also of note in this specimen are the capillaries (Cap), which are prominent as a result of the contrasting red staining of the red blood cells within them.
KEY A, acidophils B, basophils C, chromophobes Cap, capillaries HB, Herring bodies P, pituicytes