2400 - Prenatal Development

Germinal Period (0-14 Days)

The release of an ovum from the ovary, which is then fertilized by a sperm in the fallopian tube to form a zygote that undergoes cell division and develops into a blastocyst before implanting in the uterus. This stage includes the potential for identical or fraternal twins and the formation of pluripotent embryonic stem cells, which are crucial for medical research.

Pluripotent

Cells that can differentiate into various tissue types. 

Embryonic Period (Weeks 2-8)

Embryo forms from the embryonic disk; support systems develop from trophoblast cells. 

Cephalocaudal

Growth from head to tail. 

Proximodistal

Growth from the center outward. 

Organogenesis

Development of major organs; disruption can cause miscarriage or developmental malformations. 

Fetal Hearing

Developing ear sensitive to sounds – 16-18 weeks; full hearing by 27 weeks  

Fetal Vision

Developing eye can first detect light – 16 weeks; eyes are mostly developed by 26 weeks 

Fetal Learning

Physiological evidence (heart rate): 32-week-old fetus can detect a stimulus AND detect a change in the stimulus 

Teratogens

Environmental agents that cause deviations from normal development and can lead to abnormalities or death 

Examples of Teratogens

Drugs, alcohol, smoking, stress, infections, pollutions  

Stress Inoculation Hypothesis

Appropriate, manageable levels of stress during pregnancy may also benefit a child later in development