PS275 Lecture 7: PS 275- Lecture 7
Document Summary
Prenatal period: total period of time from conception to birth. Gestation period = conception to birth + 2 weeks. Changes and growth that occur in an orderly, predictable sequence (due to genetic and biological programing) 3 periods of prenatal development: period of the zygote (germinal period) Zygote divides into 2 cells, and by 48 hrs. have divided again and so on and so forth, form two layers (the one forms baby body and the other the support team) No implantation = miscarriage: period of the embryo. All the tissues and structure that will house, nurture and protect the embryo are formed. All organs and most features of the embryo begin to develop. 3 distinct layers in feature development: ectoderm. Becomes skin and nervous system: mesoderm. Becomes muscles, blood, excretory system: endoderm. Development begins with neural tube (beginning of nervous system and brain), heart and body structures (eyes, ears, mouth, arm/leg buds: period of the fetus.
