Chapter 4: Conception-Childhood Key Notes

germinal period

the first and shortest phase of prenatal development, lasting from conception to about two weeks

embryonic period

from the third week after conception until the end of the eighth week; neural tube, heart. limb buds, and organs form during this time

fetal period

starts at the 9th week of pregnancy (or 11th week of gestational age) and lasts until birth; rapid weight/brain growth

embryo

the early developmental stage of a multicellular organism, lasting from conception or implantation until the eighth week of human pregnancy before it becomes a fetus

fetus

the unborn offspring of a mammal that develops from an embryo and grows inside the womb until birth