PSYB20H3 Lecture Notes - Lecture 3: Prenatal Development, Amniotic Sac, Miscarriage
Document Summary
Stages of prenatal development: principles of growth, cephalocaudal principle dictates that development proceeds from the head to the lower part of the trunk, proximodistal principle cell migration. Development proceeds from parts near the centre of the body to outer ones. Embryo"s head and trunks develops before the limbs. The arms and legs develop before the fingers and toes. Embryonic stem cells no fixed fate or function. Cell differentiation- cell start to specialize in specific structure and function: approx. Hand development: gestation prenatal period of development b/w conception and bird. Normal range b/w 37 and 41 weeks: stages of prenatal development: 36 hrs. of fertilization zygote divides (mitosis) more complex. 72 hrs. after fertilization divided into 16 to 32 cells. Cells arrange a hollow sphere: with the inner cell mass. 2 to 8 weeks the organs and major body systems develop rapidly. While the fertilized ovum is dividing, it is also making its way down the fallopian tube uterus.
