Introduction to Development

Zygote

The newly fertilized egg that enters a period of rapid cell division.

Embryo

The developing human organism from about 2 weeks after fertilization through the end of the eighth week.

Fetus

The developing human organism from nine weeks after conception until birth.

Teratogens

Harmful agents, such as chemicals and viruses, that can reach the embryo or fetus during prenatal development and cause harm.

Fetal Alcohol Syndrome

A series of physical and cognitive abnormalities that appear in children whose mothers consumed large amounts of alcohol while pregnant.

Rooting reflex

When touched on the cheek, the infant opens its mouth and searches for the nipple.

Sucking reflex

When an object is placed in a baby’s mouth, he will suck on it.

Grasping reflex

If an object is placed into a baby’s palm, the baby will grasp the object.

Moro reflex

When startled, a baby will fling its arms out quickly and retract them, making themselves as small as possible.

Babinski reflex

When a baby’s foot is stroked, he will spread his toes.

Infancy

The first year of a child’s life.

Toddler

A child between the ages of one to three.

Childhood

The ages from 3 until 13 or puberty, whichever comes first.

Adolescence

The developmental stage from puberty until adulthood.