conception

CONCEPTION
It is the consequence of several complex events which include:

final maturation of the spermatozoa and oocyte
transport of gamete in the female genital tact
fusion of the male and female gametes
the assembly of diploid number of chromosomes

spermatogenesis
• It is the production of mature sperms and it occur in the seminiferous tubules of the testis within a period of 2 months.
• Primordial germ cells – 1spermatogonia (mitotic) – primary spermatocyte (meioticI)– secondary spermatocyte (meioticII) – round spermatid (spermiogenesis) – 4 mature spermatozoa
• Each sperm is 60 micrometer in length, and middle piece 5 micrometer in diameter

oogenesis
• This process of the production of mature egg is different from the process of spermatogenesis
• The primordial germ cell present in the wall of the yolk sac migrate to the genital ridge then differentiate to oogonia by the 12th week of the fetal life – then by mitotic division – develop primary oocyte ( up to 7 million in number)

• Then the primary oocyte undergo the 1st meiotic division which is arrested at the prophase stage and resumed just before ovulation after puberty to produce the secondary oocyte and this undergo the second division after fertilization to give the fertilized ovum and the second polar body
• The mature oocyte measures 120 micrometer in diameter
• One diploid oogonium produce one haploid mature egg

Transport of gametes in the genital tract and fertilization

• After ovulation the fimbria of the fallopian tube cover the surface of the ovary and the tube itself contracts rhythmically
• The oocyte surrounded by cumulus oophorous is transported into the tube by the sweeping movement of the fimbria and the motion of the cilia of the epithelial lining of the tube




fertilization
• When the male and the female gametes fused in the ampulla of the tube
• The spermatozoa fertilize the oocyte after undergoing the the capacitation and the acrosomal reaction these are 2 changes occur in the sperm head under influence of substances from corona radiata cells of the oocyte