KEY POINTS

■ The male gonad is the testis, responsible for spermatogenesis and the secretion of testosterone.

■ The male reproductive tract conducts the sperm from the testis into the female reproductive tract during mating.

■ The female gonad is the ovary, responsible for the production of ova and the secretion of oestrogen and progesterone.

■ The release of ova from the ovary is associated with a regular cycle of interrelated hormonal changes in the ovary and the reproductive tract and in the animal’s behavioural patterns - this is known as the oestrous cycle.

■ Fertilisation occurs in the uterine tube and the developing embryos implant in the wall of the uterine horns.

■ The extra-embryonic membranes and the embryo develop from different parts of the rapidly dividing ball of cells derived from the original fertilised ovum.