PSYC 2P12 Chapter Notes - Chapter 3: Prenatal Care, Fetus, Amniotic Sac
29 Sep 2016
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Document Summary
The first step in the development of an individual human being happens at conception. Each of us received a combination of genes that shaped our experiences for the rest of our lives. Conception occurs when a sperm penetrates an ovum. Most cells in the human body contain 23 pairs of chromosomes. The 23 chromosomes of the sperm unite with the 23 chromosomes of the ovum. A fertilized egg has 23 pairs of chromosomes. Forms a new cell called a zygote. Fraternal twins: dizygotic twins, are conceived when two eggs are fertilized by two separate sperm. Identical twins: mozygotic twins, are conceived when a single fertilized ovum separates into two parts, and each develops into a separate individual. Pregnancy: physical condition in which a woman"s body nurtures a developing embryo or fetus. Gestation: prenatal development is the process that transforms a zygote into a newborn. Tests detect human chorionic gonadotropin (hcg) in urine as early as 3rd week.
