THE PARATHYROID GLANDS
Anatomy of the Parathyroids

Four parathyroid glands are embedded, two on each side, in the thyroid gland tissue in the lower part of the front of the neck.

http://www.udel.edu/Biology/Wags/histopage/colorpage/cen/centpg.GIF

Microscopic View of the Parathyroid Gland

Since the parathyroid glands are located on the back of the thyroid, often follicle cells of the thyroid gland can also be seen.  The follicles of the thyroid are located on the right side of this slide and the parathyroid is on the left and looks like a half-circle. You can see that it is embedded in the thyroid follicles. 

Normal parathyroid gland (high power)

Like all endocrine glandular tissue, the nucleus of each parenchymal cell is round. This can help one identify endocrine tissue.Also, this tissue, like all endocrine glands, is rich in capillaries. Each cell must contact a capillary directly in order to deliver its hormone to the rest of the body. The erythrocytes in the capillaries stain bright red and are easy to see. They go single-file through the capillaries. You can see fat cells here too. The largest is located in the lower right hand corner of the picture. They are normal in adult parathyroids.