 |
Looking through the testis, you should note many seminiferous tubules in cross and oblique section, irregular connective tissue septae, and interstitial (Leydig) cells. Focus your attention on the seminiferous tubules. Identify: adventitia (lamina propria) of tubules, various stages of spermatogenesis and Sertoli cells. The latter are readily identified by the presence of an elongate "notched" nucleus with a large dark nucleolus. Locate the examples of the following stages of sperm development: spermatogonia, primary spermatocytes, spermatids, and mature spermatozoa. |
 |
Secondary spermatocytes are rarely found and cannot be differentiated from primary spermatocytes very easily. They should be visualized within your mind through the use of a now well-trained vivid imagination. Though a cell may look very much like a mature spermatozoan, if it is still part of the tubular epithelium, it is still a spermatid. It becomes a spermatozoan only when it is released. |
 |
High magnification image of the interstitial tissue between seminiferous tubules. In this interstitial tissue are three Interstitial (Leydig) cells. They have a round nucleus with a prominent nucleolus. If you look carefully you can see some secretory granules in the cytoplasm of these cells. These granules contain testosterone and will be secreted into the surrounding connective tissue where they will migrate either to the adjacent seminiferous tubules or to the capillaries nearby. This method of secretion where no ducts are involved is endocrine secretion. |
 |
Scanning Electron Micrograph of a single seminiferous tubule. The obvious structures are labeled. Other cell types are not as easy to recognize in this type of preparation. However, it does give one a feeling of the three dimentional structure of the tubule.
|
