Prenatal Development

• Cephalocaudal Principle – development proceeds from head to the lower extremities
• Proximodistal – development proceeds from the center to outer parts of the body
• Early Signs and Symptoms of Pregnancy Tender, Swollen breasts or nipples Fatigue Slight bleeding or cramping Food Cravings Nausea with or without vomiting Frequent Urination Frequent, Mild Headaches Constipation Mood Swings Faintness and Dizziness Raised Basal Body Temperature
• Germinal Stage -- From fertilization to about 2 weeks of gestational age --Zygote enters into cell division (mitosis) while making its way to the fallopian tube
• Differentiation – specialization of the cells to perform various tasks
• Blastocyst – fluid-filled sphere which floats freely in the uterus until 6th day after fertilization then it implants itself in the uterine wall
• Trophoblast – outer layer of cells that later provides nutrition and support for the embryo
• Ectoderm – outer layer (becomes outer layers of skin, nails, hair, teeth, sensory organs, and the nervous system)
• Endoderm – inner layer (becomes digestive system)
• Mesoderm – middle layer (becomes inner layers of skin, muscles, skeleton, and excretory and circulatory systems)
• Amniotic Sacs – encloses the developing embryo, protecting it and giving it a room and grow
• Placenta – allows oxygen, nourishment, and wastes to pass between mother and embryo
• Umbilical Cord – connects the embryo to the placenta
• Embryonic Period -- From 2 to 8 weeks (First 2 months) --Major body systems (respiratory, digestive, and nervous system) develop known as Organogenesis
• Critical Period – most vulnerable to destructive influences
• Spontaneous Abortion (Miscarriage) – expulsion from the uterus of an embryo that is unable to survive outside the womb
• Stillbirth – miscarriage occurred after 20 weeks of gestation (approx. 5 months)
• Males are more likely to be spontaneously aborted or to be stillborn
• Fetal Period-- From 8 weeks to Birth o Appearance of the first bone cells o Final stage of gestation
• Fetal Period --Grows rapidly to about 20x its previous length o Finishing touches o Breathe, kick, turn, etc. o Facial expressions of pain at 36 weeks o Responds to mother’s voice
• fetal period -- Fetuses know when they approach the near end of the pregnancy , Grasping reflex
• fetal period - 6 months or more fetuses can survive outside the womb ,24-37 months babies need help in breathing