Anatomy & Physiology Reproductive #13
Which is the first step in embryonic development?
Ovulation is defined as the release of an ovum from the ovary. This is not the first step in embryonic development.
Ejaculation is defined as the spontaneous discharge of semen which contains sperm. This is not the first step in embryonic development.
The first step in embryonic development is fertilization. This process is tightly controlled to help ensure that only one sperm fuses with one ovum.
- Sexual intercourse
Sexual intercourse (between a male and a female) involves the penetration of the vagina by the penis. This is not the first step in embryonic development.
Embryonic development (i.e., embryogenesis) is defined as the process by which an embryo forms and develops.
Sexual intercourse, ovulation, and ejaculation are all steps that must take place for fertilization to occur. Fertilization, however, is the first step in embryonic development. Embryonic development starts with the fertilization of the ovum by a sperm cell. Once fertilized, the ovum is referred to as a zygote.
Test Taking Tip
“First” indicates that this step must occur for embryonic development to occur.