The human body contains several interconnected systems that work together to keep us alive and functioning. The circulatory system transports blood throughout the body via the heart and blood vessels, providing cells with oxygen and nutrients and removing waste. The respiratory system intakes oxygen and removes carbon dioxide through breathing. The digestive system breaks down food through the mouth, esophagus, stomach, and intestines and extracts nutrients for the body.

1. The Human Body Systems By the Fourth Grade Computer Class

2. The human body is like a complex organization that has an important job to get done. In order to get everything done perfectly and on time, it has to use a system. Actually, the human body uses many systems that work side by side . The Human Body Systems by Bobby

3. The Body Systems Work Together The heart is like the president of the organization. Some of the body's systems are directly connected to the heart, while others are not. Even if the heart is not directly involved in the system, it still plays a part. If the heart isn't working, nothing else is working either. The heart actively participates in the circulatory system, while it just keeps an eye on the respiratory and excretory systems.

4. The Body Systems The Digestive System The Skeletal System The Circulatory System The Muscular System The Nervous System The Respiratory System

5. The Digestive System By Rowan

6. Where Your Food Goes When you eat your food, do you know where it goes? It goes into your digestive system. Your digestive system is made up of your mouth, pharynx, esophagus, liver, stomach, small intestines, large intestines, appendix, rectum, and anus! That is a lot of parts!

7. Care For Your Digestive System! Chew your food well and swallow slowly! Drink plenty of water to help move food through your digestive system!

8. Facts About Your Digestive System It takes 2 to 3 weeks to digest gum. Juices in the stomach break down the proteins. Food stays in your stomach for 2 to 3 hours. Food goes down your esophagus and into your stomach where juices break down the proteins. Then it goes down your small intestine to the large intestine and gets removed by the digestive system.

9. Get the Picture?

10. The Skeletal System By Alex

11. The Skeletal System The skeletal system is the system that supports us and gives us our shape.

12. Main Structures of the Skeletal System Two main structures form the skeletal system: cartilage and bone. Cartilage is largely composed of water and contains no nerves or blood vessels. Bones are hard on the outside. Inside they are soft, but strong. Red and white blood cells are made inside the bones.

13. The Circulatory System By Nathaniel

14. The Circulatory System The circulatory system performs many vital functions. Your heart pumps blood and nutrients to tissues all over the body. The circulatory system is also important in the removal of wastes and in several other body processes.

15. The Main Organ of the Circulatory System The main organ of the Circulatory system is the heart. The heart's primary function is to pump blood to all parts of the body, bringing nutrients and oxygen to the tissues and removing waste products.

17. The Muscular System The Muscular System is made up of 630 muscles. By Kelli

18. The Muscular System Helps Your Body Move Most muscles work together in pairs. One muscle pulls while the other muscle relaxes. When you bend your arm the biceps muscle pulls and the triceps muscle relaxes. When you make your arm straight, the biceps muscle relaxes and the triceps muscle pulls.

19. The Function of Muscles Muscles are very important. They help you do almost everything — from pumping blood throughout your body to lifting your heavy backpack. You control some of your muscles and others, like your heart, do their jobs without you thinking about them at all.

20. Interesting Facts About Muscles Muscles are bundles of cells and fibers. Muscles work in a very simple way. All they do is tighten up--that is, contract--and relax. You have two sets of muscles attached to many of your bones which allow them to move. There are 630 active muscles in your body and they act in groups. Muscles can only pull. They never push.

21. Did you know? You use 17 muscles when you smile. You use 43 muscles when you frown .

22. Nervous System by Jesse The main parts of the Nervous System are the Brain, the Nerves, and the Spinal Cord.

24. The Brain The brain is much more complex than the spinal cord. It has many divisions within it. The brain stem controls most of the life systems commands such as breathing and heartbeat. The cerebellum controls balance and the coordination of muscles to move. The cerebral cortex is the most advanced part of the brain. This is where conscious thought takes place.

25. The Spinal Cord The spinal cord is a long bundle of white nerve matter that is found in the middle of the spinal column. It is a link between the brain and the body.

26. Respiratory System By Paige

27. Function of the Respiratory System The primary function of the respiratory system is to supply the blood with oxygen in order for the blood to deliver oxygen to all parts of the body. The respiratory system does this through breathing. When we breathe, we inhale oxygen and exhale carbon dioxide. This exchange of gases is how the respiratory system gets oxygen to the blood.

28. The Respiratory System Air is breathed in through the nasal cavity and/or mouth and down through the throat (the pharynx). The air passes down the trachea (the windpipe), through the left and right bronchi, and into the lungs. Oxygen in the blood is delivered to body cells.