Physical Development - Development of Nervous System

The human nervous system begins its development just three weeks after conception and continues rapidly after birth, supporting the child’s ability to learn, move, and sense the world.

• The nervous system grows very quickly during the embryonic period, before birth.
• In these early weeks, the head is much bigger compared to the rest of the body.
• The first eight weeks are a sensitive, important time for forming a healthy nervous system.

• The nervous system continues to grow quickly after birth, especially in the first 3 to 4 years.
• At birth, the brain weighs about 1/8 of the whole body’s weight.
• At 10 years, brain weight is 1/18 of body weight.
• At 15 years, brain weight is 1/25 of body weight.

• Starts Early: The Nervous system begins 3 weeks after conception.
• Prenatal Growth: Rapid growth in the first 8 weeks; the head is large.
• Postnatal Growth: Fast development in the first 3–4 years after birth.
• Brain Weight at Birth: 1/8 of body weight.
• Brain Weight Later: 1/18 at 10 yrs, 1/25 at 15 yrs.