Question

The structure absent in Frog’s testis is
(a) Seminiferous tubules
(b) Seminal vesicles
(c) Sertoli cells
(d) None of the above

Answer 1

Hint: Testes represent the male reproductive organ in males. The structure that is absent in the frog’s testis performs the function of nutritional support to the developing spermatozoa in the testes of human males.

Complete step by step answer:
The sexes in frogs are separate and they exhibit sexual dimorphism i.e the male and female can be distinguished morphologically. The male reproductive system of Frog consists of a pair of the testis lying anterior- ventrally to the kidneys. The internal cavity of testes is filled with coiled seminiferous tubules where sperms are produced by spermatogenesis. The tubules are interspersed with interstitial tissues secreting a male sex hormone to produce secondary sexual characters in males. No Sertoli cells or nurse cells are present in the testis.

So, the correct answer is ‘Sertoli cells.’

Additional Information:
- The sperms produced in the testes travel through tubules named ‘vasa efferentia’ which opens into Bidder’s canal.
- From Bidder’s canal, the sperms are carried to the transverse collecting tubules before it reaches the urogenital tract.
- The urogenital tract is a common tract for both urine and sperms. Before opening into the cloaca, it dilates to form a seminal vesicle to store the sperms temporarily.
- During amplexus i.e mating in frogs, the sperms leave the seminal vesicle, and through the cloaca, sheds into the water via the cloacal aperture. Cloaca is a common chamber for the discharge of fecal matter, urine, and sperms.

Note:
- Frogs show sexual dimorphism where both female and male can be differentiated morphologically too. - Male has vocal sacs and amplexusory pads. Both are usually functional during the mating season where the males use vocal sacs to croak so as to call the female.
- The amplexusory pads are used to grip the female during copulation.