Human Growth and Development

Chapter 2: Building Blocks of Development Overview This chapter provides an introduction to human development from conception to birth, emphasizing genetics, prenatal stages, and biological systems. Additionally, the chapter covers the nervous system, explaining how neurons and neurotransmitters communicate and describing the functions of major brain regions. Together, these topics lay the foundation for understanding the biological and environmental factors shaping development. Learning Objectives: At the end of the chapter, you should be able to: ●​ Understand basic concepts of genetics and chromosomal abnormalities. ●​ Describe the different stages of prenatal development. ●​ Define and understand what teratogens are. ●​ Explain the steps of the birthing process. ●​ Describe and name parts of the nervous system and their functions. ●​ Understand how neurons communicate (Understand how the CNS communicates). ●​ Identify parts of the brain and neurotransmitters. A. Foundations of Biological Development Biological development is shaped by genetic, cellular, and physiological processes that influence growth and maturation throughout life. Concepts of Genetics Development begins with sex cells (gametes):

●​ Females produce egg cells . ●​ Males produce sperm cells .

●​ During fertilization, a sperm and an egg combine to form a zygote , which is the first cell of a developing organism. Chromosomes and Genetic Material: ●​ The zygote undergoes cell division, growing from one cell to many. ●​ Inside every cell nucleus are chromosomes, which carry genetic information. ●​ Somatic (body) cells contain 46 chromosomes (23 pairs):

＞ ​ Half come from the mother. ＞ ​ Half come from the father.

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