PSYC 2400 Chapter Notes - Chapter 4: Gestational Age, Prenatal Development, Organogenesis
Document Summary
Period of development between conception and birth. Age of an unborn baby, usually dated from the first day of an expectant mother"s last menstrual cycle. Fertilized ovum or zygote, grows into an embryo and then a fetus. Molecules that are switched on after fertilization. Begin sculpting arms, nads, fingers, vertebrae, ribs, a brain and other body parts. Development proceeds in a head to tail direction. Upper parts of the body develop before lower parts of the trunk. Parts of the body near the center develop before the extremities. Attachment of the blastocyst to the uterine wall, occuring at about day 6. Characterized by rapid growth and development of major body systems and organs. Process in which the organs and major body systems develop rapidly. Severely defective embryos usually do not survive beyond the first trimester of pregnancy. Fetus adds layer of fat in preparation for birth. Natural expulsion from the uterus of an embryo that cannot survive outside the womb.
