SCANNING ELECTRON MICROSCOPIC OBSERVATION OF THE HUMAN THYROID FOLLICLES
The luminal surface of the follicular cells in the human thyroid was observed by scanning electron microscope. The results obtained were as follows: 1. The internal form of the follicles is mostly spherical, and the walls are generally made out of hexagonal flat-surfaced epithelial cells. 2. The apical surface of the follicular epithelium is covered with the irregularly oriented numerous microvilli. 3. One or two central cilia are located at the central portion of the follicular cells. The length of the cilia is usually constant. However, the length of the microvilli is variable depending upon individual cells. 4. The pseudopods appear scatteringly on the surface. Basically their shape is spherical with or without indentation at the vertex.