The muscular system of the human body consists of skeletal muscle, cardiac muscle and smooth muscle. Skeletal muscle, as its name suggests attaches primarily to the skeleton and moves voluntarily or by reflex. Cardiac muscle is the muscle of the heart and contracts involuntarily. Smooth muscle on the other hand is found in the blood vessels, eyes, hair follicles and the walls of the hollow organs including the stomach and intestines.
Functions of the muscular system
1. The muscular system creates movement
The primary function of muscular system is to produce voluntary gross and fine movements. Large movements include walking, standing, running, playing sports and lifting weights and smaller movements include chewing, closing the eyes, writing and talking are all produced by the muscular system of the body.
2. It protects the organs
The abdominal muscles and the muscles of the lower back help protect the vital organs of the body. For instance, bones do not protect the abdominal cavity like the rib cage protects the heart and the lungs. The rectus abdominus, or “six pack” muscle, the obliques found at the sides of the torso and the transverse abdominus running side to side across the front of the abdominal cavity protect the organs from the front and sides. Similarly, the lats, quadrates lumborum and the psoas muscles, which run from the bottom area of the ribs to the pelvic bones protect the organs from the back of the abdominal cavity.
3. The cardiac muscle pumps blood
The contraction of the heart muscle is involuntary and primarily controlled by the heart’s own electrical system. In the human body, the heart is responsible for receiving blood back from your muscles, pumping it into the lungs then pumping it out into the arteries to supply the entire body.
4. Smooth muscle aids digestion
The smooth muscles of the stomach and intestines work to process the food we ingest. The involuntary contractions in the stomach and intestines aid in digestion and in moving the food along the digestive tract, ultimately directing indigestible substances to the rectum.
5. Smooth muscle ensures blood flow
There are smooth muscles in the walls of the blood vessels. When the heart contracts, the arteries expand to accept blood. The smooth muscles in your arteries contract to push the blood throughout the blood vessel systems in the body. This is why when plaque builds up on the inside of the walls of the arteries, the arteries harden and the muscles in your arteries do not contract properly.