Final answer:
In birds, the cloaca is the structure involved in mating. Spermatogenesis occurs in the seminiferous tubules of the male reproductive system. Oocytes are released during ovulation and enter the oviduct in the human female reproductive system.
Step-by-step explanation:
The structure involved in mating in birds is the cloaca. In birds, unlike mammals which have separate openings for reproductive and excretory systems, the cloaca serves as a common chamber for the digestive, excretory, and reproductive systems. It facilitates the transfer of sperm during mating when the cloacae of two birds touch in a process known as 'cloacal kissing'.
Regarding spermatogenesis, it occurs in the seminiferous tubules within the testes of males. This is where the sperm develops through a series of stages, starting from spermatogonia to ultimately become mature spermatozoa. The seminiferous tubules play a critical role in the male reproductive system.
Oocytes are released from a human ovary during the process of ovulation and enter the oviduct, which is the pathway leading to the uterus where fertilization can occur if sperm is present. This release is triggered by hormonal changes within the menstrual cycle.