Reading: RR&K, Chapter 20
SLIDE 81b pituitary gland (rhodocyan)
(RR&K p623, Fig.1; p625, Fig. 1,2,3,4,5; p602, Fig. 20.4)
Under low power, identify the foll owing regions of the pituitary gland: the anterior lobe (pars distalis; showing groups of bright red cells and blue cells), the intermediate lobe (pars intermedia; somewhat deeper blue; contains follicles filled with colloid) and the posterior lobe (pars nervosa; filamentous, pale blue).
The cells of the anterior lobe include acidophils, basophils, and chromophobes. The cytoplasm of acidophils stain bright red, basophils deep blue, and chromophobes gray. The rhodocyan stain reveals various shades of red and blue which probably reflect additional cell heterogeneity. The point of your examination is to recognize that different cell types stain distinctively, and thus you need not be concerned with these variations. Numerous blood sinusoids are present which is typical of an endocrine gland. As seen at higher power, the glandular cells of the intermediate lobe have preserved their epithelial character much more than the cells of the anterior lobe. Note frequent occurrence of follicles filled with homogeneous material, and the deep incursions of this lobe into the pars nervosa. The posterior lobe or neurohypophysis (pars nervosa) consists mainly of a dense tangle of nerve fibers and cytoplasmic processes of pituicytes, stained pink in the section. Also present are Herring bodies. These structures are homogeneous and pink. What are these bodies and what substance is present in these structures? Many of the nuclei in the posterior lobe are pituicytes, but some endothelial cells are also present. Do not confuse these two cell types.
Check list for SLIDE 81b:
SLIDE 81a pituitary gland (PAS)
(RR&K p623, Fig.1; p625, Fig. 1,2,3,4,5; p602, Fig. 20.4)
Under low power, identify the following regions of the pituitary gland: the anterior lobe (pars distalis; showing groups of bright red cells and blue cells), the intermediate lobe (pars intermedia; somewhat deeper blue; contains follicles filled with colloid) and the posterior lobe (pars nervosa; filamentous, pale red).
The cells of the anterior lobe include acidophils, basophils, and chromophobes. The cytoplasm of acidophils and chromophobes do not stain. However, basophils stain red indicating the presence of carbohydrate moieties.
The glandular cells of the intermediate lobe usually forms follicles filled with colloid that stains red with PAS.
The posterior lobe or neurohypophysis (pars nervosa) consists mainly of a dense tangle of nerve fibers and cytoplasmic processes of pituicytes, stained pink in the section. Also present are Herring bodies. These structures are homogeneous and pink.
Check list for SLIDE 81a:
SLIDE 84a adrenal gland, human (H&E)
(RR&K p633, Fig.1,2,3; p635, Fig. 1,2; p616, Fig. 20.15)
Orient yourself by locating the capsule, cortex and the medulla. The capsule is dense connective tissue that supports the incoming arteries. Classify the tissue seen outside the capsule. The cortex is subdivided into three zones (zona glomerulosa, zona fasciculata, zona reticularis) of steroid producing cells. The zona glomerulosa is not complete all around the gland. The glomerulosa cells are smaller and less vacuolated (therefore, stain with eosin) than the cells of the zone fasciculata, and are arranged in small round clusters. The cells of the zona fasciculata are arranged in rows separated by long sinusoids. These cells are pale due to the presence of numerous vacuoles that had contained lipids (see FIGURE 06 on the next page). The zona reticularis has cells that are smaller and eosinophilic. Yellowish lipofuscin pigment may be present in some cells of the reticularis.
The medulla contains large muscular veins and chromaffin cells that secrete catecholamines. The central veins have cushions of smooth muscle. Occasional nerve cell bodies are seen near the central vein in only a few of the slides used for this laboratory. If your slide has these nerve cell bodies, share your slide with the other students. The nerve cell bodies can be distinguished by their large size and the presence of Nissl substance in their cytoplasm. The predominant cell type in the medulla is the chromaffin cell (see FIGURE 07 on the next page) which appears either white or light blue on your slides. Do not confuse the blue staining of the chromaffin cells with the Nissl bodies of nerve cell.
Check list for SLIDE 84a:
FIGURE 06 Adrenal cortical cells (EM)
(RR&K p617, Fig.20.16)
This electron micrograph reveals the typical characteristics of a steroid producing cell. The cell contains numerous lipid vacuoles, and the tubular cristae of the mitochondria are atypical but common in steroid producing cells. What organelles are required for steroid production? How are the steroids secreted from the cell? How could you determine which steroids are being produced in this cell?
Check list for FIGURE 06: 
FIGURE 07 Adrenal medullary cells (EM)
(RR&K p619, Fig.20.18)
This is an electron micrograph of two different chromaffin cells. One secretes epinephrine while the other secretes norepinephrine. The presence of secretory vesicles is consistent with the secretory function of these cells and suggests that secretion is probably regulated. Note that unlike the steroid producing cells of the cortex, these medullary cells lack lipid vacuoles and have mitochondria that appear normal. What organelles are required for the production and secretion of these catecholamines? How are the catecholamines secreted from the cell? How could you determine which catecholamine is being produced in these cells?
Check list for FIGURE 07: 
SLIDE 83a parathyroid, monkey (H&E)
(RR&K p629, Fig.1; p613, Fig. 20.13)
Locate the thyroid and parathyroid glands on your slide. The major portion of glandular tissue on this slide is the thyroid gland. Locate the follicles that comprise the bulk of the thyroid gland. The interior of the follicles is a colloid filled with thyroglobulin, a very large protein that is stored until endocytosed by the follicular cells. Note that the follicular cells that line the follicles range from squamous or low cuboidal to cuboidal. The squamous cells are presumed to be less active that the cuboidal cells. In some areas the follicular epithelium may appear to be stratified because of the plane of the section. The parafollicular cells (C cells) that make thyrocalcitonin are difficult to distinguish in the typical (H&E) stained section. Note the abundant capillary network adjacent to the follicles.
The parathyroid glands can easily be seen by the unaided eye as one or two dark masses within this section of the thyroid gland. The parathyroid glands are composed of two major parenchymal cell types, the principal cells and the oxyphils. The majority of the cells are principal cells. These cells are small, dark-staining cells. The oxyphil cells are larger cells that typically display an eosinophilic cytoplasm. Only a few oxyphils are present in the typical section. The function of these cells is not yet known. Typical of endocrine glands, numerous capillaries are present.
Check list for SLIDE 83a: 
The Endocrine system is responsible for intercellular communication via hormones, which can act over long distances and relatively long time periods. This unit examines various endocrine organs and their cellular structure.