Psychology: Prenatal Development

Prenatal Development

Prenatal Development

During ovulation, an ovum is released from one of the ovaries and then begins a slow journey through a fallopian tube. If fertilization occurs, the resulting combination (XX or XY) of the sex chromosomes in the fertilized ovum determines the baby’s sex. The cell will go through cell division and continues to grow until it takes form of a human being.

ovulation: The release of an egg cell (ovum) from the ovary.

ovaries: The female gonads, which secrete the female sex hormones estrogen and progesterone and produce mature egg cells.

fallopian tube: A straw-like tube between an ovary and the uterus through which an ovum passes after ovulation. 

Fertilization: the uniting of a sperm and the ovum

Zygote: a fertilized ovum or egg cell

Stages of Prenatal Development 

germinal stage: The stage of prenatal development that spans the period from fertilization through implantation. 

•  For the first three or four days following conception, the mass of dividing cells moves about the uterus before implantation. The process of implantation is not completed for perhaps another week or so. 

embryonic stage: The stage of prenatal development from implantation through about the eighth week of pregnancy during which the major organ systems begin to form. 

• embryo: The developing organism at an early stage of prenatal development.
  •  About three weeks into pregnancy, two ridges fold together to form the neural tube, from which the nervous system will develop.
  •  The head and blood vessels also begin to form
  •  By the fourth week, a primitive heart takes shape and begins beating
• amniotic sac: The uterine sac that contains the fetus.
• placenta: The organ that provides for the exchange of nutrients and waste materials between mother and fetus. 
• umbilical cord: a tube between the mother and her developing child through which nutrients and waste products are conducted

fetal stage: The stage of prenatal development in which the fetus develops, beginning around the ninth week of pregnancy and lasting until the birth of the child.

•  All of the major organ systems, as well as the fingers and toes, are formed by about the 12th week of prenatal development
•  mother will feel the first fetal movements around the middle of the fourth month
• three months prior to birth, the organ systems mature. the heart and lungs become capable of sustaining independent life.

Threats to Development

spina bifida: A neural tube defect in which the child is born with a hole in the tube surrounding the spinal cord. Most cases are mild and do not involve any significant problems, but in severe cases, problems such as difficulty walking or performing daily activities without assistance may result.

teratogen: An environmental influence or agent that may harm the developing embryo or fetus.

rubella: A common childhood disease that can lead to serious birth defects if contracted by the mother during pregnancy (also called German measles).

sudden infant death syndrome (SIDS):  The sudden and unexplained death of infants that usually occurs when they are asleep in their cribs.

fetal alcohol syndrome (FAS): A syndrome caused by maternal use of alcohol during pregnancy in which the child shows developmental delays and facial deformities