Gametogenesis is the process by which male and female germ cells undergo chromosomal and morphological changes in preparation for fertilization. In males (spermatogenesis), germ cells in the seminiferous tubules undergo two meiotic divisions to form four haploid sperm. In females (oogenesis), germ cells in the ovarian cortex undergo one meiotic division and stop until ovulation, when the remaining division is completed to form one haploid ovum and three polar bodies. Both processes result in gametes with half the normal chromosome number required for fertilization.

1. (1)GAMETOGENESIS
 In preparation for fertilization both male & female germ cells undergo a
chromosomal & morphological changes which is known as
Gametogenesis
Types
 Spermatogenesis - Development of mature spermatozoa or sperm
 Oogenesis – Development of mature ova
1

2. (2)Mieosis
2

3. 3

4. Spermatogenesi
s
46, 2N
46 , 4N
23, 2N
23, 1N
23, 1N
4

5. Oogenesis
46, 2N
46 , 4N
23, 2N
23, 1N
23, 1N
5

6. 6

7. SPERMATOGENESIS
 Time of beginning – Shortly before puberty

Site – Seminiferous tubule
COMPLETES TWO MEIOTIC DIVISIONS
 CREATES FOUR EQUAL HAPLOID SPERMS
OOGENESIS



Time of beginning – Intra uterine life
Site – Ovarian cortex
STOPS AT PROPHASE OF THE MEIOTIC DIVISION UNTIL OVULATION.
 AT THE TIME OF OVULATION,THE OOCYTE GOES TO METAPHASE OF SECOND
MEIOSIS.
 CREATES 1 OOCYTE AND 3 POLAR BODIES

7

8. Sperm Anatomy
Streamlined to swim through vagina, cervix, uterus
duct
 Acrosome – part of head, contains enzymes to
penetrate egg
 Haploid nucleus
 Mitochondria to supply energy (sugar in semen)
 Flagellum to propel sperm
8

9. +
9

10. 10