Paragraph on “Human Muscles and Movement” complete paragraph for Class 9, Class 10, Class 11 and Class 12

Human Muscles and Movement

Movement of any part of the body would not be possible without muscles. Our body has about 650 muscles which move various parts of the skeleton. The largest muscles are the ones on our buttocks and the smallest ones are located in our ear. Half of our body weight is generally contributed by our muscles. Muscles are living tissue in our body which have the ability to contract based on the signals received from the brain. They are connected to the bones in the skeleton and contraction of these provides movement to the bones. Muscles are of three types i.e. skeletal muscles, cardiac muscles and smooth muscles. Skeletal muscles, as their name suggests cover the bones in our skeleton and are voluntary in nature since they can be, moved at will. These muscles allow the movement of the bones through contraction. Smooth muscles are found in the bladder digestive system etc. These muscles are involuntary in nature since they function automatically. The last type is the cardiac muscle which is found only in the heart. These too function automatically without impulses from the brain. Muscles need energy and fuel to function, this requirement is met by the blood vessels which constantly provide them with oxygen and nutrients. Muscles are made up of thin fibers, in turn each of these fibers are composed of more thin fibers called fibrils. Fibrils contain molecules of action and myosin which allow movement with a sliding action. Muscle movement is initiated by nerve impulses from the brain which cause chemical changes in the fibrils. Moving a leg or lifting an arm sounds simple but involves the movement of a large number of muscles in unison like a team. All muscles must be used regularly and the best way to do so is to regularly exercise the body. Healthy muscle fibers would not have fat in it and would have a good flow of oxygen. Lack of oxygen in the muscles causes them to contract and this gives us cramps.