Body Systems A body system refers to a group of organs, whic

Well now, let’s have a look at body systems, I’m going to run through them all very quickly and then we can have a look at them in detail. Now first, ah, have a look at the illustration showing some of the body’s organs. Now you should know most of these already. When we think of organs we usually think of the heart, lungs and kidneys. But, of course, the eyes, ears and brain are also organs and there are many more. Organs are part of the body that do a special job. Now, a group of organs working together is called a system. There are 10 main systems in the human body and they all work together to keep the body going.
  Now let’s have a quick look at these systems.
  Now first—the skeletal system. That’ s the bones and the things that hold them together, that we call connective tissues. The skeletal system is the framework of the body. It gives the body its shape and form and it protects the heart, lungs and the brain.
  The muscle system has the role of moving the body. It also pushes food through the body and makes the blood circulate.
  Now you can see how these systems work together. The bones couldn’t move without the muscles. And all the systems are controlled by the nervous system. This is made up of the brain, the spinal cord and the nerves. And this system controls all muscle movement. It also controls your senses and makes it possible for you to learn and remember things.
  Now some people say that the nervous system is the most important system of all but that isn’t really true because all the systems have to work together to keep us alive. They are all essential to life. So you can’ t really say that one is more important than another.
  Now, the digestive system. The stomach and the intestines are the main parts of this system. They have the job of processing food to provide energy for the body. Food is broken down to a simpler form so that it can be absorbed into the blood. The waste products are removed from the body through the rectum at the end of the intestines.
  The respiratory system consists of the windpipe and lungs and it takes air into the body. It also separates out the oxygen needed to turn the food you eat into energy for the body. The lungs also get rid of the carbon dioxide, which is collected from the cells by the blood.
  The blood, the heart and all the blood vessels form the circulatory system. Now this system carries the food and oxygen around the body. It also collects the waste from the cells and fights bacteria-germs--in the body.
  The urinary system is made up of the kidneys and bladder. And this system filters certain wastes from the blood and removes them from the body as urine.
  Now can you see how all these systems are working together--pouring things into the blood and filtering other things out of it—and keeping you alive?
  Next is the lymphatic system. Now you probably haven’t heard of this one and it’s fairly hard to describe. Lymph is a clear liquid which comes from the blood. It leaves the blood vessels and moves throughout the body, picking up wastes as it goes—things that the body doesn’t want. When it has done its job the lymph flows back into a large blood vessel near the neck. The wastes that it has picked up are then filtered out of the body through the blood.
  The endocrine system could be called the body’s chemical control. This system is made up of special glands found in many parts of the body. These glands give out hormones which are like chemical messengers. These tell different body systems how to operate. They control things like how tall people become and how energetic they feel.
  Finally, the reproductive system. This consists of a group of organs involved in making new human ’beings. In males, the main organs of the reproductive system are the testes and in the females they are the ovaries and the uterus.
  Now, er, let’s look at some of these systems in more detail ...