The muscles of the body enable individuals to stand upright, walk and pick up heavy objects. Those very same muscles enable the heart to beat, the lungs to breathe and internal organs to function. A variety of organs as well as muscle tissues are included in the body's muscular system, each with a specific job to do. Muscular tissues are found throughout the body and include more than those bulging biceps or six-pack abs. Muscular tissues promote movement, states Discovery Kids.com.
Smooth Muscular Tissue
Muscle tissue may be smooth and are the tissues that line blood vessels and organs such as the stomach and intestines. Smooth muscle tissue function and mobility is usually involuntary, which means a person has no control over it, such as the rhythmic contractions of the digestive tract and the bladder and contractions of blood vessels and the uterus (especially during childbirth). Smooth muscle tissues are not connected to bones and are controlled by the autonomic nervous system. Smooth muscle tissue pushes food along the digestive tract and controls the flow of blood through blood vessels. Most of the digestive and excretory organs have smooth muscular tissue, so these organs can be said to make up the muscular system.
Muscle tissue can be skeletal, which helps hold the skeletal frame together, provide strength and mobility and enables humans to walk upright. Skeletal muscles are the most well known and familiar of muscle organ systems. From the large gluteus maximus (buttocks) to the tiny flexor muscles found on the finger, skeletal muscles provide extension and contraction movements to the limbs, provide strength and support for the body, protect our internal organs and enable us to walk, jump, sit, run and carry. Some of the most common and large muscles in the human body are the abdominals, the pectorals, gluteus maximus and the quadriceps. Each of these muscle groups are connected to tendons, ligaments or skeletal tissues, so the skeletal system can be said to make up the muscular system.
The heart is actually a muscle, known as the cardiac muscle. The heart is only one of 650 muscles found in the human body and is one of the strongest. The heart is made up exclusively of cardiac tissues and is one of the most muscular organs in the body, beating at an average of 72 times per minute (or approximately 3.5 billion times during a lifetime), states the Texas Heart Institute.