WALA GROWTH, DEVELOPMENT AND HEALTH WALT • Explain how growth takes place • Find out the difference between growth and development • Describe how diet and exercise affects growth and development • Discuss how smoking affects health KEYWORDS • Growth • Development • Embryo • Health • Tobacco • Nicotine STARTER Growth means getting bigger. 1. Explain what happens as a person grows, to make their body get bigger? 2. Some young children do not get enough protein or energy in their diet. Explain why they may not grow very tall. GROWTH • Every person on Earth began their life as a single cell. This cell divided to produce two cells. Each of these cells got bigger, then divided again. • To begin with, the cells are all the same. They produce a little ball of cells called an embryo, eventually a baby. • This all happens in the mother’s body. By the time the baby is born, it is a miniature human being. It continues to grow until it is about 18-20 years old. • Cells contain a lot of protein. Energy is needed to make cells divide. DEVELOPMENT The change from a single cell to an adult human involves more than just growth. As the tiny embryo grows into a baby, all its different tissues and organs are formed. As the baby grows into a child, its leg muscles and bones become stronger, so that it can walk and then run. Its brain develops, as it learns to talk and to play with toys. These changes are called development. DEVELOPMENT 0-1year Child 2-4 years Toddler 4- 11years Child 12-17years Adolescent 18years Adult EXERCISE AND HEALTH Taking regular exercise is a really good thing to do. • This uses some of energy in the food you eat each day, stopping you from storing 100 much as fat. • It also makes the heart and muscles work hard, so that they become strong. • Exercise can also make people feel more cheerful and positive about life. SMOKING • Smoking cigarettes damages the smoker's health. It also damages the health of people around them who accidentally breathe in cigarette smoke. • Tobacco contains many different harmful substances such as: A. Nicotine Tobacco smoke contains nicotine. Nicotine can help someone to stay alert. Nicotine is addictive, it is difficult to manage without it, once you are used to smoking. This is why smokers find it so difficult to stop smoking. Nicotine damages the blood vessels in a smoker's body. It makes them get narrower, so it is harder for blood to get through them. Smokers are more likely than non-smokers to develop heart disease. SMOKING • B. Tar Tobacco smoke contains a mixture of dark, sticky substances called tar. Some of the chemicals in tar cause cancer. Cancer happens when cells start dividing out of control and spread to other parts of the body. Smoking increases the risk of getting many different kinds of cancer, including lung cancer. SMOKING • C. Carbon monoxide Carbon monoxide is a poisonous gas. When it gets into the body, it combines with haemoglobin inside red blood cells. This stops haemoglobin from doing its normal job, which is to combine with oxygen and transport it to all the body cells that need it. So a smoker's cells don't get enough oxygen. They cannot carry out enough respiration, so don't have enough energy. SMOKING D. Particulates Tobacco smoke contains tiny particles of carbon and other materials, called particulates. This get trapped inside the smoker's lungs. This makes the walls of the alveoli break down. Instead of having millions of tiny alveoli in the lungs, the smoker has a lot of big spaces. This is makes it difficult for them to get enough oxygen into their blood. HOMEWORK 1. Describe the following terms; • Growth • Development • Health 2. State the developmental milestones of a human being.
