Question

Draw a labelled diagram of the sectional view of a human seminiferous tubule. (Six parts to be labelled)

Answer 1

Hint: Seminiferous tubule is located inside the testicular lobule of testis and is the site of meiosis and the formation of spermatozoa by the process of gametogenesis . Between seminiferous tubules some interstitial cells are found that produce a steroid hormone called testosterone .

Complete answer:
Testis-The shape is oval, pink. The testicles are placed in a thin pocket of skin called the scrotum . Testicles is located outside the abdomen. This is due to the fact that for normal sperm production, the temperature in the testicles must be below body temperature. The rise in temperature kills sperm tissue.
Testis is divided into compartments called testicular tubules which in in turn contains one to three highly coiled seminiferous tubules.
Two types of cells present in the seminiferous tubules. These are spermatogenic cells (germ cells) and Sertoni or support cells (nurse).
The inner lining of seminiferous tubules is called a germinal epithelium and is made of Primary germ cells as well as some supporting cells that provide nutrition to primary germ cells.
The primary germ cells multiply by repeated mitotic division. The cells produced after the final mitotic divisions are known as spermatogonia The spermatogonia do not divide for sometime but increase by accumulating nutritive materials from the nutritive cells. Such supporting cells are called cells of Sertoli. Spermatogonia takes nutrition from the surrounding cells. The enlarged spermatogonia are now known as primary spermatocytes.
Primary spermatocytes divided by meiosis first mitotic division results in the formation of secondary spermatocytes.
Secondary spermatocytes undergo second meiotic division and result in the formation of spermatids.
By the process of Spermiogenesis spermatids are transformed into spermatozoa.
Spermiogenesis- The process of transformation of spermatids that leads to the production of spermatozoa is known as Spermiogenesis .

Sectional view of seminiferous tubule

Vasa Efferentia: Vasa Efferentia is a pair of duct structures arising from rete testis and extending up to epididymis.
Epididymis: The epididymis is connected with the vas deferens. It is a long wound tube located on the back of each testicle. The function of the epididymis is to store and transport sperm produced by the testicles.
Vas deferens: The vas deferens are the muscle ducts that extend from the scrotum from the groin and into the urethra, the tube that leads out of the bladder. The end of each vas deferens expands and forms an ejaculation duct that can contract and expel the stored sperm.
Penis: The penis is a muscular tubular organ made of loose tissue with spaces in between. This is called erectile tissue. When stimulated, the erectile tissue fills with blood, making the penis erect and tense, allowing it to penetrate the female vagina and discharge semen. The male external genitalia is represented by penis.
Section of seminiferous tubule

Note: Spermiogenesis- The process of transformation of spermatids that leads to the production of spermatozoa is known as Spermiogenesis . Since sperm are very active and motile cells, they must remove excess material from developing sperm in order to ensure true motility, and sperm undergo a high degree of specialization in several stages.
After Spermatogenesis the sperm head became embedded in sertoli cells and finally released from the seminiferous tubule by a process known as spermiation.
Sertoli cells were discovered by Enrichno Sertoni, an Italian histologist. As the name suggests, germ cells produce sperm through spermatogenesis, and nurse cells provide nutrition for developing sperm.