PSY 220 Study Guide - Midterm Guide: Menarche, Osteoarthritis, Ejaculation

• School: Stony Brook University
• Department: Psychology
• Course: PSY 220
• Professor: Stacey Scott

Document Summary

Conception: midway through the menstrual cycle, every 28 days or so, females ovulate: An ovum (egg cell) ripens, leaves the ovary, and begins its journey through the fallopian tube to the uterus. The zygote contains the 46 chromosomes that are the genetic blue-pri(cid:374)t for the i(cid:374)di(cid:448)idual"s development. Embryologists who study early growth and development divide prenatal development into 3 stages or periods: the germinal period, the embryonic period, and the fetal period. 2 weeks) for the first week or two, the zygote divides many times through mitosis, forming the blastocyst, a hollow ball of about 150 cells that is the size of a head of a pin. When the blastocyst reaches the uterus around day 6, it implants tendrils from its outer layer into the blood vessels of the uterine wall. During this short time, every major organ takes shape, in at least a primitive form, in a process called organogenesis.