The muscular system consists of 650 muscles and it supports the movements required to walk, talk, eat and stand. It makes up more than 40 percent of the body’s total weight. The muscular system controls daily functions, maintains posture and circulates blood. It is divided into three types of muscles: skeletal muscles, smooth muscles and cardiac muscles.
The skeletal muscles are used to perform conscious functions. In order to take one step, the muscular system uses 200 muscles, and the average number of steps taken daily is 10,000. The muscular system uses 17 muscles to smile and 43 muscles to frown. The smooth muscles are the weakest muscles and they are located inside of the organs and blood vessels. Cardiac muscles are located in the heart and are responsible for pumping and circulating blood. The only muscle in the muscular system that that never gets tired is the heart. The heart works constantly and the average human heart beats more than 60 times per minute.
When the body is cold, the muscular system contracts involuntarily. Once muscles contract, energy is released to warm the body, which cause shivers. Muscle is three times as dense as fat. The smallest muscles are located in the middle ear. The strongest muscle is the masseter located in the mouth.