The muscular system consists of three main types of muscle tissue. We have smooth tissue, we have cardio tissue, often known as the myocardium, and we have skeletal tissue. So, the smooth tissue, it’s throughout the body, we find in the digestive system, reproductive system, circulatory system, and the urinary system. It’s all over the body. We don’t have control and they’re involuntary control over them. We will cover that later.
The next kind of muscle we move on to is cardiac muscle. It’s only found in the heart and it’s controlled by sinoatrial node and set heart rhythm is generally about 72 beats per minute, so this is at rest in a normal healthy person. Normal heart rhythm like that is called autorhythmicity. That’s quite a complicated word that you might not have heard before, but the function of cardiac muscle is to pump blood O2 around the body.
The third muscle we’re going to look at is skeletal muscle. Skeletal muscle works by attaching a muscle to a joint via a tendon. Now, this is controlled by the somatic nervous system so it’s considered as voluntary. The skeletal muscle system will provide us with locomotion and other body movements. For example, the maintenance of posture. As I’m stood here, my skeletal muscles are working on and off to keep me standing upright but I’m not thinking about that particularly at the moment. So, it also has some jobs with storing and transporting of substance within the body such as glycogen. The skeletal muscle also generates warmth. Muscles, in general, have four properties. The first one being elasticity in the sense that they can get shorter and longer. They have contractility, and they also have electrical excitability, and they also have extensibility.