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Principles of Physical Development

Growth is influenced by the two major trends, cephalocaudal development (from head to tow,  where your brain is developed first ) and proximodistal development (from the midline outward where your organs will be more developed than extremities such as your limbs and arms). In early childhood, the average child grows 2½ inches and between 5 to 7 pounds a year. Girls are slightly smaller and lighter than boys.

Hormonal influence

Hormones play a vital role in the body’s physical development. They are chemical messengers released by the endocrine system and sent throughout the body to regulate various physiological processes and behaviors. In addition to influencing physical development, hormones also affect cognitive and socioemotional growth.

During early childhood, two hormones are especially important for physical growth. The first is Human Growth Hormone (HGH), which supports growth in nearly all parts of the body except the central nervous system (CNS). Growth in the CNS is primarily influenced by the Thyroid Stimulating Hormone (TSH). Together, these hormones help regulate the overall growth process during early developmental stages.

During puberty, the release of sex hormones—primarily estrogen in females and testosterone in males—plays a central role in the development of sexual organs and secondary sex characteristics. We will explore these changes in more detail later in this module.

Video 3.1.1. Explaining the two systems that is responsible for producing and releasing hormone in our body.