Normal parathyroid gland.
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.