Within the body of man and most animals, God has created a group of organs that causes a uniquely animal characteristic, that of movement. The more than 600 muscles in our body allow, among other things, graceful movements, movement of food and even cause our passage into this physical world at birth. Let’s examine how movement is made possible by the muscles of our bodies.
There are three distinct types of muscles: the skeletal muscles, the cardiac muscle and smooth muscles. Each of these has been designed with a very specific type of makeup that allows them to function in very different ways. The overall functions of the muscle system include movement, heat production, stabilization of body position and protection.
The skeletal muscles are also called voluntary or striated muscle. This refers to how they are controlled and how they look under microscopic examination. Basically, they attach to bones and cause the skeletal system to move. They are controlled by direct signals of the brain when we want to move in a certain way. They contain two very distinct types of proteins — one thick and one thin. This arrangement causes a striped appearance, giving it the name striated muscle. These muscles can produce some tremendous forces, as in the case of “hysterical strength” where humans have done superhuman feats. This is probably possible because the muscle filaments all function at the same time, instead of alternating on and off.
The smooth muscles are also called involuntary or visceral muscles. This refers again to how they are controlled and look. These muscles are found in organs such as the digestive system, eyes, urinary system and many other places where we have muscles that are controlled by our autonomic nervous system. They operate as they are needed and are controlled by nerve impulses from the organs to the brain and turned on and off. Our food is moved through the digestive system without our thinking about it.
The cardiac muscle is that muscle which is found only in the heart. These muscles are self-exciting as they have their own electrical impulse system. Our heart must pump blood every minute, hour and day of our lives for us to remain alive and yet it still finds time to rest for about half of our lives.
The muscle system is indeed a wonderfully coordinated system controlled by the brain. It takes the signals from the central nervous system that allows us to get all of the muscles moving together to make coordinated movement possible. As we watch a baby learning to walk, we are seeing the brain and muscles learning to communicate back and forth. It will take much trial and error before everything is “fine tuned” just right and the baby takes off walking.
As we use our muscles, they increase in size as more fibers are added to the muscle. This process is called hypertrophy. When we do not use the muscle, it will remove muscle fibers and decrease in size or atrophy. This allows us not to carry around muscles that we are not going to need for the rest of our lives. As we increase our physical activity, we will begin to grow the needed muscle for our activity. The inspired apostle Paul indicated that physically we would grow when we made an effort, just like we would in our spiritual lives. Sometimes athletes say, “No pain, no gain.” This reflects that we must physically move our muscles in order to get stronger.
Our bodies are indeed “the temple of God.” We should make every effort to keep that temple in the best physical condition so that it can be used by God for service to him.
