Introduction to Psychology/Child and Adolescent Psychology/Prenatal Environment

Prenatal development is the development of an organism before its birth.

Stages of Prenatal Development

 * 1) Germinal stage – conception to 2 weeks
 * 2) *Begins at conception and ends when the zygote implants itself in the mother's uterine lining.
 * 3) *Between 8 and 12 days after conception, implantation occurs. This is when the zygote embeds itself in the inner lining of the mother's uterus.
 * 4) Embryonic stage – 3 to 8 weeks after conception
 * 5) *blastocyst differentiates to form three cell layers in the embryo: the ectoderm, mesoderm, and endoderm.
 * 6) **The ectoderm is the outer layer of the cell mall, and during the embryonic stage it gives rise to the nervous system, sensory receptors, and outer skin layers.
 * 7) **The mesoderm becomes the circulatory system, skeleton, muscles, excretory system, reproductive system, the outer layer of the digestive tract, and the inner layer of the skin.
 * 8) **The endoderm will eventually become the respiratory system and the remainder of the digestive system.
 * 9) *chronological development following conception
 * 10) **3rd week - vulnerable brain cells and spinal cord form from the neural tube
 * 11) **3rd and 4th week - placenta and umbilical cord form
 * 12) **by 4 weeks - eyes begin to form, torso continues to form, heart tissue begins to beat, arm buds appear
 * 13) **by 5 weeks - arms are developed and legs buds begin to form
 * 14) **during 8th week - organogenesis is complete, signaling the end of the embryonic stage and beginning of the fetal stage
 * 15) Fetal stage - week 9 to birth (38–40 weeks)
 * 16) *chronological development following conception
 * 17) **9 through 12 weeks - first arm and leg movements begin, reflexes appear, sex organs develop.
 * 18) **17 through 20 weeks - mother begins to feel movement, heartbeat can be heard with a stethoscope.
 * 19) **by 24 weeks - fat forms and rapid weight gain begins
 * 20) **26 through 28 weeks - lungs are mature enough to allow breathing
 * 21) **28 though 40 weeks - major organ systems are functional and brain develops rapidly.

Teratogens

 * preterm births occur before 37 weeks of gestation
 * low birth weight is less than five and half pounds (two pounds lighter than average)


 * Fetal Alcohol Syndrom (FAS)
 * overall growth deficiency, head and facial malformations, and dysfunction of the central nervous system
 * effects of alcohol use
 * effects of cocaine use
 * effects of cigarette smoking
 * sexually transmitted diseases
 * effects of stress
 * sexually transmitted diseases
 * effects of stress
 * effects of stress
 * effects of stress