The body consists of many important organs. An organ is part of the body that does a special job. Organs are made up of tiny cells. BODY PARTS HEART AND BLOOD The heart is one of the major organs of the body. It is constantly pumping blood around the body. Your heart, your blood and your blood vessels are all part of your CIRCULATORY SYSTEM. Blood moves food and oxygen around the body. It circulates around the body through 3 kinds of blood vessel: 1. Arteries 2. Veins 3. Capillaries The heart pumps the blood around the body so food and oxygen can get to all the cells. The heart is protected by the rib cage. LUNGS The lungs are like two spongy bags filled with millions of tiny air sacs. Each lung has a good blood supply. The lungs, nose and windpipe are all part of the RESPIRATORY SYSTEM. The lungs give oxygen to the blood and remove carbon dioxide. This happens when you breathe in and out. If you stopped breathing for more than a minute or two, you would quickly die. Without oxygen, brain cells only live for a few minutes. BREATHING The process of breathing: 1. We breathe in air through our nose and mouth 2. It flows down our throat through a tube - Trachea 3. This pipe brings the air to your lungs 4. The air travels along tubes called Bronchioles 5. It then travels to little sacs at the end of the Bronchioles called Air Sacs or Alveoli 6. The air passes through the Alveoli into tiny blood vessels 7. Unwanted carbon dioxide passes from the blood, through the alveoli walls, into the lungs and out through the nose and mouth as you breathe out. When you exercise your muscles need more oxygen and food. The heart beats faster to get this food and oxygen to the muscles. MUSCLES Every move we make (e.g. running, dancing, smiling) all depend on muscles. Muscles are bundles of fibres that tense and relax to move different parts of the body. There are 2 kinds of muscles: 1. Voluntary Muscles Muscles you can control and move when you want to 2. Involuntary Muscles Muscles you can't control e.g. heart - works automatically Muscles always work in pairs. At joints muscles pull on bones - one muscle gets longer and the other muscle gets shorter, pulling the bone. SKELETON You have a Skeleton on the inside of your body. It is made of over 200 bones. Bones are very tough and light. The skeleton does three jobs: 1. Protects the body parts E.g. skull - protects the brain ribcage - protects the lungs 2. It supports your body and lets you stand up. 3. It lets you move. Bones have joints so the skeleton can bend. SENSES Our senses tell us what is going on in the world around us. We have 5 main senses: 1. Sight - eyes 2. Hearing - ears 3. Smell - nose 4. Taste - mouth and tongue 5. Touch - skin NERVES AND BRAIN The brain is split into 2 halves and it weighs about 1.5Kg. Inside the brain there are billions of nerve cells. Signals are sent to/from the brain along nerves to/from body parts. The network of nerves in the body is called the NERVOUS SYSTEM. FOOD AND WASTE Before your body can use any of the food you eat, it must be broken down. This is called DIGESTION. The stomach, intestines, liver, food pipe and mouth are all part of the DIGESTIVE SYSTEM. When you put food into your mouth you chew it until it is soft, you can then swallow the food and it will end up being pushed down a lung tube called the Gut. Dangerous waste is removed from the body by the Kidneys. These products are then removed via the Bladder. THE HEALTHY BODY The human body is very good at taking care of itself. But to stay healthy it needs the right food and regular exercise. Most of the food we eat is used by the body for energy. A healthy, balanced diet is one that includes the right amount of the following: * Carbohydrates * Fats * Protein * Vitamins and Minerals * Fibre