Human Body System Facts

The human body’s numerous systems are interdependent. That means they depend upon each other for proper functioning; each human body system must function well for the others to function. When one is compromised, the others suffer as well. An exception to this is the reproductive system, which can be compromised and the rest of the body can continue to function well.

Skeletal System

The bones in our bodies make it possible for us to stand up and they give us our shape. A newborn baby has about 350 bones, but as people grow up some of the bones fuse together making a single bone. An adult has only about 206 bones.

Respiratory System

Respiratory system deals with breathing. We take in air through our noses and mouths and bring it into our lungs. Healthy lungs are pink. Smoking causes lungs to look black, and smoking decreases a person’s “lung capacity,” or ability to breathe.

Circulatory System

The circulatory system refers to the heart pumping blood through the veins and arteries throughout the body. The heart is a muscle that is shaped essentially as a shell with four open spaces inside. This muscle pumps blood through the four chambers of the heart and around the body.

Immune System

The immune system refers to the body’s ways of defending itself against invading viruses and sickness. One way is with white blood cells. Blood is made up of both red blood cells and white blood cells. White blood cells fight off disease. When a person is sick, his body produces more white blood cells to fight off the illness.

Muscular System

Muscles are attached to bones and enable us to move. The heart is a muscle that moves on its own, but many muscles move “voluntarily,” that means the person controls them. When a person has a tick or facial twitch, this is called an involuntary movement because he is not controlling the muscle’s movement. There are about 600 muscles in the human body.