Are the brain, heart, and spinal cord fully functional at birth?

The brain, heart, and spinal cord have distinct developmental timelines, and while they are present at birth, they are not all fully functional in terms of adult capabilities. The heart is fully functional at birth, allowing the newborn to circulate blood and receive oxygen. The spinal cord is also functional, as it is crucial for basic reflexes and vital functions.

However, the brain undergoes significant development after birth. At birth, certain brain structures are developed enough to support basic functions, but higher-order processes and mature functioning of various brain regions evolve over time as the child grows and learns.

Thus, the most accurate understanding is that while the heart and basic brain functions are operational, the complexity and full functionality of the brain continue to develop significantly during early childhood.