click below
click below
Normal Size Small Size show me how
Anatomy/Physiology
Chapter 21
| Term | Definition |
|---|---|
| Alleles | One of two or more different genes for a particular characteristic |
| Amnion | An embryonic membrane that holds the fetus suspended in amniotic fluid; fuses with the chorion by the end of the third month ofgestation |
| Amniotic fluid | The fluid contained within the amnion; cushions the fetus and absorbs shock |
| Autosomes | Chromosomes other than the sex chromosomes; for people there are 22 pairs of autosomes in each somatic cell |
| Cleavage | The series of mitotic cell divisions that take place in a fertilized egg; forms the early multicellular embryonic stages |
| Embryo | The developing human individual from the time of fertilization until the eighth week of gestation |
| Genotype | The genetic makeup of an individual; the genes that are present |
| Gestation | The length of time from conception to birth; the human gestation period averages 280 days |
| Heterozygous | Having two different alleles for a trait |
| Homologous pair | A pair of chromosomes, one maternal and one paternal, that contain genes for the same characteristics |
| Homozygous | Having two similar alleles for a trait |
| Implantation | Embedding of the embryonic blastocyst in the endometrium of the uterus 5 to 8 days after fertilization |
| Labor | The process by which a fetus is expelled from the uterus through the vagina to the exterior of the body |
| Parturition | The act of giving birth |
| Phenotype | appearance of the individual as related to genotype; the expression of the genes that are present |
| Sex chromosome | The pair of chromosomes that determines the gender of an individual; designated XX in females and XY in males |