Human Reproduction of Class 12
The primary sex organs : Testis and ovary form sperm and ovum respectively. Primary sex organs are also called gonads. These are mesodermal in origin.
Secondary (accessory) organs help in the transportation, storage, maturation and fertilization of the gametes.
- In male these include vasa efferentia, vasa deferentia, epididymis, seminal vesicles, ejaculatory duct, prostate gland, urethra, Cowper’s glands and penis.
- In female these are oviduct (fallopian tube), , uterus, vagina, Bartholin glands and vulva.
Fertilization is facilitated by the external genitalia (penis) which depends upon the type of fertilization (external or internal) as per the mode of life, i.e., external in aquatic and internal in terrestrial (by copulation).Secretion of hormones (or pheromones) from various glands act as sex-attractant. Color, shape, form and behaviour (fore play) of the fair-sex also add in the process.
In frog the amplexus (pseudocopulation) occurs, male mounts over the female inducing it to release ova. Reptiles (except few) and birds, even being terrestrial, have no external genitalia but true copulation occurs by cloaca to cloaca transfer of sperm.