Muscles are soft tissue found in both animals and humans. The cells of the muscles comprise protein filaments of actin and myosin that slide past one another, which produces contraction and changes both the length and the shape of the cell. The term muscle is derived from the Latin word “musculus” which refers to a little mouse.
- Maintaining and changing body posture.
- Circulation of blood cells throughout the body.
- Movement of internal organs, such as the contraction of the heart and the movement of food through the digestive system via peristalsis.
The human muscular system includes more than 600 muscles, which make up about 40 to 50% of the total body weight. These are attached to bones, blood vessels, and other internal organs of our body and are mainly composed of skeletal muscles, tissue, tendons, and nerves. The muscle of the human muscular system is composed of a kind of elastic tissue.
The energy required for the functioning of muscles is predominantly powered by the oxidation of fats, carbohydrates particularly and from the stored energy molecules adenosine triphosphate.
Types of Muscles
In Humans, they are classified into three types:
- Skeletal muscles
- Cardiac muscles
- Smooth muscles
Based on the muscle action, They are further classified into:
- Voluntary muscles
- Involuntary muscles
Every muscle is a different organ made of blood vessels, skeletal muscle tissue, nerves, and tendons. Muscle tissues are found in the heart, blood vessels, and digestive system.
There are three kinds of muscle tissues, namely cardiac, visceral and skeletal.
- Cardiac Muscle: This muscle is present only in the Heart and responsible for supplying blood all over the body. It is also an involuntary muscle since it cannot be controlled. When the brain signals adapt to the rate of contraction, the cardiac muscle triggers itself to contract. The natural pace of the heart is composed of cardiac muscle tissue and triggers other cardiac muscle cells to shrink. The cardiac muscle cells are straight which reveals that they seem to have dark and light stripes when seen under a microscope. The protein fibers arrangement within the cells is responsible for these dark and light stripes.
- Visceral Muscle: These are found in the organs like intestines, blood vessels, and stomach. It is said to be an involuntary muscle because it cannot be controlled directly by the conscious mind but controlled by the unconscious part of the brain. These also known as a smooth muscle
- Skeletal Muscle: These are the voluntary muscle tissue that can be controlled in conscious conditions. All physical actions that a human performs like walking, writing. The skeletal muscle is responsible for moving the body parts that are connected to the bone.