VAN 211: Veterinary Histology and Embryology (2+2)

GAMETOGENESIS

• The most important characteristic of every living organism is the ability to reproduce to perpetuate the species.
• The reproductive cells, which unite to form the new individual, are known as gametes. In all higher vertebrates, the gametes from male are called spermatozoa and the larger, food – laden gametes formed within the female are termed ova/ovum.
• The gametes themselves and the cells that give-rise to them constitute the germplasm of an individual. The other cells of the body, which take no direct part in the production of gametes, are called somatic cells.
• The process by which the gametes are produced is known as gametogenesis.
• It includes
• Spermatogenesis in male
• Oogenesis in female.
• Generally, gametogenesis is divided into four major phases
• Origin of germ cells and their migration into gonads.
• The multiplication of germ cells by mitosis.
• Reduction division/Meiosis.
• The final stage of maturation and differentiation of the gametes into spermatozoa/ova.