The basic parts of the human body are the head, neck, torso/te:sao, arms and legs. Our bodies consist of a number of biological systems that carry out specific functions necessary for everyday living. The job of the cardiovascular system (circulatory system) is to move blood, nutrients, oxygen, carbon dioxide, and hormones, around the body. It consists of the heart, blood, blood vessels, arteries and veins. In fact the cardiovascular system is not only responsible for delivering blood and oxygen, but also for transporting nutrients, hormones and waste throughout the body. All of these are carried in the blood, of which an average adult has about 5 liters. The digestive system consists of a series of connected organs that together, allow the body to break down and absorb food, and remove waste. It includes the mouth, esophagus, stomach, small intestine, large intestine, rectum, and anus. The liver and pancreas also play a role in the digestive system because they produce digestive juices. The endocrine system consists of eight major glands that secrete hormones into the blood. These hormones, in turn, travel to different tissues and regulate various bodily functions, such as metabolism and growth. The immune system is the body's defense against bacteria, viruses and other pathogens that may be harmful. It includes, lymph ducts, lymph nodes, the spleen, bone marrow, white cells, etc. The lymphatic system includes lymph nodes, and lymph vessels. It also plays a role in the body's defenses. Its main job is to make and move lymph, a clear fluid that contains white blood cells, which help the body fight infection. The nervous system controls both voluntary action (like conscious movement) and involuntary actions (like breathing), and sends signals to different parts of the body. The central nervous system (CNS) includes the brain and spinal cord, and is responsible for processing the information which is sent to or received from the peripheral nervous system which is made up of the body's nerves. The brain processes information while the spinal cord acts as a delivery system for the information and impulses. The peripheral nervous system consists of nerves that connect every other part of the body to the central nervous system. Information transmitted through the central nervous system tells our bodies how to react in a certain situation, such as when we want to take a step the brain tells our knee joint to bend, or when we touch something hot, we receive information giving us a burning sensation.