ALU 301: A&P Chapter 21: Human Development & Genetics with Complete Solutions.

Alleles - ANSWER-Gene possibilities. A person has two alleles for each protein or trait, they can be the same or different. Amnion - ANSWER-an embryonic membrane that holds the fetus suspended in amniotic fluid; fuses with the chorion by the end of the third month of gestation Amniotic fluid - ANSWER-the fluid contained within the amnion; cushions the fetus and absorbs shock Autosomes - ANSWER-chromosomes other than the sex chromosomes; for people there are 22 pairs of autosomes in each somatic cell Cleavage - ANSWER-the series of mitotic cell divisions that take place in a fertilized egg; forms the early multicellular embryonic stages Embryo - ANSWER-the developing human individual from the time of implantation until the 8th wk of gestation. At 12 days the embryonic disc is a plate of cells within blastocyst. As they divide, the plate folds. Genotype - ANSWER-the genetic makeup of an individual; the genes that are present Gestation - ANSWER-the length of time from conception to birth; the human gestation period is 280 days Heterozygous - ANSWER-having two different alleles for a trait Homozygous - ANSWER-having two similar alleles for a trait Implantation - ANSWER-embedding of the embryonic blastocyst in the endometrium of the uterus 5 to 8 days after fertilization. The outer layer of cells is called a (trophoblast), the inner cell mass is called (embryoblast) Labor - ANSWER-the process by which a fetus is expelled from the uterus through the vagina to the exterior of the body. Stage 1: Dilation of cervix, uterus contracts, sac is forced into cervix, water breaks. Stage 2: Delivery of infant. Oxytocin is released causing more powerful contractions Stage 3: Delivery of Afterbirth. Part