Growth and Development

Abstract

This chapter assesses the linked processes of brain growth and development. Each human life begins with the union of a sperm and an egg. Embryogenesis is the process by which the fertilized egg divides repeatedly to produce the 37 trillion cells that make up a person. But embryo development is about far more than just this dramatic increase in cell number. It also involves the formation of all the specialised cell types of the body, and their organization into tissues and organs. Initially, the embryo is just a ball of cells called a blastocyst. But then a dramatic transformation takes place called gastrulation, which is a key event in the formation of a human being. While these are the gross structural changes underlying brain development, equally important are the cellular changes. The development of the human brain occurs at such a rapid rate that a newborn baby’s brain has almost the same number of neurons as that of an adult. However, brain growth continues after birth due to the creation of new glial cells and connections between neurons.