Know the germ layers and what tissues each forms. Know the mechanism of sex determination and which ducts develop or regress in both genders. Know inter-species differences in uterine anatomy. Describe differences in cervical anatomy between cows and pigs. Describe differences in ovarian anatomy between cows and mares. Know about primordial, primary, secondary and tertiary follicles and the cell layers of the mature follicle. Know the portions of the oviduct and where fertilization occurs. What mechanisms enable a bull to raise his testes?