The Human Body The Digestive System Food provides us with energy, vitamins, and minerals that our body needs. The job of the digestive system is to break the food down into substances the organs and cells in our body can use. Fun Fact: The length of our digestive system is around 20 – 30 feet. Did you know 20 feet is about the same height of a giraffe! Five Major Stages Of the Digestive System Stage one: Chewing Chewing makes it easier to swallow food because it breaks up big pieces into little pieces. Fun fact: Your saliva has a special ingredient called enzymes that help in breaking down starchy foods such as potatoes. Stage Two: Swallowing Swallowing is not as simple as it seems. The food does not just go straight into your stomach without some help. Your tongue first pushes the food to the back of your throat. Then, your throat muscles force the food down the esophagus that will lead to the stomach. Fun fact: We all have a flap called the epiglottis that automatically blocks off our windpipe to make sure the food does not go the wrong way. You will choke if the food goes the wrong way! Stage Three: The Stomach When food reaches your stomach, they will hang around for about 4 hours. As the food “hangs around”, your enzymes will break down things like protein that your body can use. The good thing is that the stomach also helps us from getting sick by killing all the bad bacteria. Fun fact: An adult stomach can hold about 1.5 liters of material. Stage Four: The Small Intestine There are two parts in the small intestine. The first part works with juices from the liver and pancreas to continue to break down our food. The second part, is where the food gets absorbed from the intestine and into our body through the blood. Fun fact: The small intestine is about 7 meters long and the surface area is about the size of a tennis court! Stage Five: The Large Intestine The large intestine is the “exit” for the food that the body does not need or can’t use. The food leaves the body as waste (poo). Fun fact: The large intestine is only 1 meter long so its shorter then the small intestine. The only reason it is called “large” is because it is wider. The Respiratory System Your body needs oxygen to survive and the job of your respiratory system is to bring the oxygen into your body and remove the carbon dioxide from your body. Carbon dioxide comes from your cells and too much of it can be deadly. Fun Fact: You breathe in and out anywhere from 15 – 25 times per minute! The Main Organ Of the Respiratory System The Lungs Your lungs are basically sacs that fill with oxygen when you breathe. Your heart pumps blood into the walls of your lungs where it absorbs oxygen and releases carbon dioxide. Fun Fact: If you hold your breath for too long, your brain will force you to breathe. Cilia Tiny mucous covered hairs called Cilia act as a filter in your airway to trap foreign particles and germs from getting with the air that you breathe. When you cough or sneeze, you get the foreign particles out of your body. The Nervous System The nervous system is where your brain sends and receives information about what is happening in the body and around it. Fun Fact: The nervous system is made up of billions of nerve cells (also called neurons) which join together to make nerves. Nerves send impulses through the body. Two Main Parts Of the Nervous System First Part: Central Nervous System The central nervous system includes the brain and the spinal cord. The brain is basically “the The spinal cord is the main boss” of your body. It controls pathway for information everything you do even when connecting the brain to the you are asleep by sending and second part of the nervous receiving messages through system (peripheral nervous nerves. system) Second Part: Peripheral Nervous System The peripheral nervous system is basically the nerves together that carries messages to and from the central nervous system. It sends information to the brain and carries out orders from the brain. Two Main types of nerves: Sensory Nerves: Motor Nerves: Signals the brain to tell what is going on in the Allows the brain to outside world. Your 5 control our senses are part of the sensory nerves. muscles. The Skeletal System The skeletal system provides the shape and form of our bodies. It also protects our internal organs and allows us to move our bodies such as walking, running, or writing. It consists of bones, cartilage, joints, ligaments, tendons, and other connective tissues. Fun Fact: When a baby is born, the skeleton is made up of around 300 bones. Adults on the other hand end up with 206 bones because some bones have fused together. Six Major Functions Of the Skeletal System 1. Production of blood cells 2. Support 3. Movement 4. Protection 5. Storage of ions 6. Endocrine Regulation Protection Your cranium ( Skull ) protects Your ribs protect Your vertebrae (spine, your brain and your heart and backbones) protect your eyes. lungs. spinal cord. The longest Bone in the human Body Thigh Bone ( Femur ) The Smallest Bone in the human Body Stapes bone (found in the middle ear) Only 0.11 inches long! What’s a Bone made of? The outer layer is a compact bone that is hard, dense, and tough. Inside this layer is a spongy bone which is lighter and a little bit flexible. In the middle of some bones is the bone marrow where new cells are always being produced for the blood. If you want your bones to become hard and strong, drink milk and eat lots of dairy products like cheese and yogurt because they all contain calcium. Calcium strengthens your skeleton! The Muscular System There are 3 types of muscles: Skeletal Muscle Smooth Muscle The skeleton is covered by layers Found in the walls of many organs of skeletal muscle. Each muscle such as the bladder, womb, and is attached to two or more bones intestines, where it contracts to so that when the muscles contract propel food along. and expand, they create movement. Cardiac Muscle Contracts throughout life to pump blood from the heart to the lungs and around the body. Fun Fact: There are more than 600 muscles in the body! Tendons Tendons connects muscles to bones. Muscle Memory Exercising Muscle memory is when you practice When you exercise, your muscles something over and over again. It become bigger, stronger, and more allows you to become more skilled at flexible. If you don’t use your certain activities such as sports and muscles, they will shrink and music. Always remember that practice become weak! makes perfect! Fun Facts About Muscles! You shiver because there are hundreds of muscles expanding and contracting to produce heat and make you warmer. It takes 17 muscles to smile and 43 muscles to frown. Remember to always smile (less muscles to use)! The strongest muscle is in our jaw and it is used for chewing. The Circulatory System The circulatory system is made up of the heart, Blood, and Blood vessels. Heart Your heart is about the size of your clenched fist. Blood The heart pumps blood to all Your blood is colorless the parts of the body. liquid called plasma. Red blood cells deliver oxygen to the cells in the body and Blood vessels carry back waste gases. Three main types of White blood cells are part of blood vessels: arteries, your body’s defense against veins, and capillaries. disease. The Main Organ Of the Circulatory System The Heart Your heart is a muscle and it is located a little to the left in the middle of your chest. The blood that the heart pumps provides your body with oxygen and nutrients as well as carries wastes away. Your heart has two sides (pumps): The right side receives blood from the body and pumps it to the lungs. The left side does the opposite. It receives blood from the lungs and pumps it out to the body. Blood Vessels Arteries: Carries blood away from the heart. Veins: Carries blood back to the heart. Capillaries: The smallest type of vessel. It forms a network connecting the smallest arterioles with the smallest venules. Fun Fact: The Body of an adult contains over 60,000 miles of Blood vessels! Top 10 Body Organs #1 - The Brain The brain is the most important organ of the human body. It is responsible for everything you need in order to keep on living such as breathing, heartbeat, coordinating actions and thoughts, regulations, movement, emotions and blood pressure. You would not be alive without your brain. #2 - The Heart Your body cannot function without the heart. The blood pumped by the heart reaches all the body organs in your body. If your heart stops pumping, your whole body mechanism will fail, therefore, resulting in death. #3 - The Spleen The spleen contains many fluids and blood which is circulated inside the body. It removes old or damaged red blood cells and if a child receives sudden blood loss, the spleen will contract to force replacement blood into the circulation. #4 - The Lungs It is impossible to live without your lungs. They work together to help you breathe. Your right lung is a little bit larger than your left lung. #5 - The Intestines Your small intestine is responsible for the absorption of nutrients from food into the bloodstream.