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Ch. 4 Terms
Terms
Term | Definition |
---|---|
cell | the smallest unit of life that is able to reproduce itself |
sperm | the male sex cell |
ovum | the female sex cell; also called the egg |
conception | the union of the ovum and sperm cells |
zygote | the single cell formed at conception; also called a fertilized egg |
fallopian tubes | two hollow tubes that connect to the uterus and have fingerlike projections that reach toward each ovary |
uterus | the organ in which the baby develops and is projected until birth |
genetic factors | traits that are passed through the genes |
chromosomes | threadlike structures that carry genes in living cells |
dominant traits | traits that always show in a person even if only one gene of the pair is inherited for the trait |
recessive traits | traits that typically do not show in a person unless both genes for the trait are inherited |
multiple pregnancy | pregnancy in which two or more babies develop |
fraternal | term describing children from multiple pregnancies who develop from two ova and differ in genetic makeup |
chorion | membrane that surrounds the baby in the uterus |
identical | term describing children from multiple pregnancies who develop from one fertilized ovum and have the same genetic makeup |
prenatal development | the development that takes place between conception and birth |
germinal stage | the first stage of prenatal development, which lasts about two weeks after conception |
amnion | a fluid-filled sac that surrounds the baby in the uterus |
placenta | an organ filled with blood vessels that nourishes the baby in the uterus |
umbilical cord | the cord that connects the baby to the placenta |
embryo | term used to describe a baby in the embryonic stage of development |
cartilage | Soft, elastic, flexible tissue that provides structure for the body |
fetal stage | the third stage of pregnancy, lasting from about nine weeks after conception to birth |
fetus | used to describe a baby in the fetal stage of development |
quickening | movements of the fetus that can be felt by the mother |
age of viability | the age of which most babies could survive if they were born (28th week of pregnancy) |