PSYB20H3 Chapter 3: Chapter 3
Document Summary
Gestation prenatal period of development, between conception and birth: 37-41 weeks, 3 stages germinal, embryonic, and fetal, zygote embryo fetus. Limbs are later ones because they are further out. Toes and fingers are last to develop. Growing outwards = cell migration movement of newly formed cells away. Stem cells from point of origin: embryonic stem cells have no fixed fate or function, can become any cell in the body neuron, fingernail, heart, anything, cell differentiation- cell start to specialize in specific structure and function. 350 different types: focus of research in regenerative research. Offer potential for treating new diseases ex. Can have ethical issues around it people against abortions believe that life starts at conception, therefore should not use other stem cells because that life has already started. Cell death apoptosis or cell suicide: normal part of the developmental process, selective death becomes essential, happens to let the fetus become more developed, ex. hand development webbed fingers.
