NextPrevious

Human Growth and Development

Introduction

How do the terms zygote, embryo, and fetus differ?

All three terms refer to the individual developing within the uterus of a woman following conception. Fertilization between sperm and ovum produces a zygote, a single cell consisting of 46 chromosomes. It is called a zygote during the first week of development. At the end of the first week of development, the zygote becomes an embryo. It is called an embryo from the second week of development through the eighth week of development. Beginning at the ninth week of development, it is called a fetus.



Close

This is a web preview of the "The Handy Anatomy Answer Book" app. Many features only work on your mobile device. If you like what you see, we hope you will consider buying. Get the App