PSYCH 7A Lecture Notes - Lecture 20: Blastocyst, Prenatal Development, Fetus

• School: UC-Irvine
• Department: Psychology
• Course: PSYCH 7A
• Professor: lofgren

Document Summary

Embryonic period (2nd week - 8th week) Zygote: an egg that has been fertilized by a sperm cell. During the germinal period the cells divide. Differentiation: specialization in structure and function of cells. After a week, the mass of cells (now called a blastocyst) consists of 100 cells. The outer part of the blastocyst attaches to the uterine wall, forming the placenta. The blastocyst"s inner cells become the embryo. 9 weeks embryo looks like a human! 6 months organs developed enough to give fetus a chance at survival. Teratogens: harmful substances that can reach the embryo or fetus by the placenta. Placenta: keeps potentially harmful substances from reaching the embryo/fetus. When an egg is fertilized by a sperm it becomes a(n) [zygote] and starts dividing. Next, it attaches to the [placenta] and becomes an [embryo] and the major organs begin to form. Eventually, it develops enough to become recognizably human and is now called a [fetus].