Four parathyroid glands are embedded, two on each side, in the thyroid gland. Like all endocrine glandular tissue, the nucleus of each 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.

On the right side of the slide are follicles of the thyroid gland.  Embedded in the thyroid is the parathyroid, located on the left side of the slide.