Spermatogenesis:
The process of formation of sperms in seminiferous tubules of the testis of the male animal is termed as spermatogenesis. In mammals, testis have serveral coiled tubules in it called the seminiferous tubules. Sperms are formed in these tubules. The inner wall of seminiferous tubules is made up of germinal epithelium whose cells are cuboidal.
Oogenesis:
Oogenesis takes place in the ovaries. Unlike ***** formation that starts at puberty, egg formation begins before brth-but is completed only after fertilisation. Oogenesis cansists of three phases: (a) Multiplication, (b) Growth phase, (c) Maturation phase.
(a) Multiplication phase: During foetal development, endodermal cell of yolk sac enter into ovary and begins oogenesis.
(b) Growth phase: It is prolonged and slow. Oogonia form rounded masses or eggs nests at the tiple of egg tubes of pfluger.
(c) Maturation phase: Meiosis occurs. Nucleus shifts towards animal pole and undergo meiosis-I.
