The muscular system allows us to move, flex and control our bodies. Practicing yoga is a good example of the voluntary use of the muscular system.
The word Muscles refer to all contractile tissue.
The term muscle comes from the Latin word mus, which means “mouse,” because the movement of muscles looks like mice running around under our skin.
Due to the contractile property muscle tissue become short and thick in the response of nerve impulse.
Muscles then relax back to their original length once that impulse is removed. When contracting, the muscles do not simply shorten but exert a force as they become shorter.
This alternate contraction and relaxation are what causes movement. Muscle cells are elongated and resemble strands of metal such as those found in cables.
Muscle tissue is constructed of bundles of these strands that are referred to as muscle fibers. These fibers are approximately the diameter of human hair.
Under the direction of the nervous system, all the muscles provide for the motion of some type for your body.
Also Read: Lymphatic system – Organs associated and functions of the lymphatic system
Types of Muscles
The body has three major types of muscles: skeletal, smooth, and cardiac. We begin with a general description and comparison of these three muscle types and then get more specific about each type.
- Skeletal muscles are voluntary muscles, which means they are under conscious control and derive their name because they are attached to the skeleton.
- The fibers in skeletal muscles appear to be striped and are therefore called striated (striped) muscle.
- These muscles allow us to perform external movements—running, lifting, or scratching, for example.
- These are the muscles we try to develop through exercise and sports and also so we look good at the beach.
- Smooth muscle is involuntary and not under our conscious control. It is also called smooth muscle because it does not have the striped appearance of skeletal muscles.
- This involuntary muscle is found within certain organs, blood vessels, and airways. Because it is the muscle of organs, it is sometimes called visceral muscle.
- Smooth muscle allows for the internal movement of food (peristalsis) in the case of the stomach and other digestive organs.
- In addition, smooth muscle facilitates the movement of blood by changing the diameter of the blood vessels (vasoconstriction and vasodilation) and also the movement of air by changing the diameter of the airways found in our lungs.
- The specialized cardiac muscle, which is striated like skeletal muscle. This muscle type is found solely in the heart.
- It makes up the walls of the heart and causes it to contract. These contractions cause the internal movement (circulation) of blood within the body.
- Fortunately, cardiac muscle, like smooth muscle, is an involuntary muscle. Imagine if we had to think each time for our heart to beat.
Characteristics of muscles- Muscular System
- All muscles share certain characteristics such as the ability to stretch, called extensibility.
- For example, if you would swallow a large bolus of food, the smooth muscle in your esophagus must be able to stretch and allow it to pass or it would become painfully stuck.
- In addition, they all share contractility, which is the ability to contract or shorten muscle fibers forcefully.
- All muscles exhibit excitability, which is muscle response to stimulation by either nerves or hormones.
- Finally, all muscles show some level of elasticity, which is the ability to return to the original resting length after being stretched.
Some important features of muscles:-
- Muscles make up almost half the weight of the body.
- There are 650 different muscles in the human body.
- The size of your muscles is influenced by how much you use them.
- This is why speed skaters have large leg muscle Individual elongated muscle cells can be up to 12 inches, or 30 centimeters, in length.
- At about the age of 40, the number and diameter of muscle fibers begin to decrease, and by age 80, up to 50 percent of the muscle mass may be lost.
- Exercise and good nutrition help to minimize this loss.
Functions of muscles:-
- Muscles help us in the movement of the body by the contraction.
- Muscles also help to maintain the posture of the body
- It also stabilizes the joints of the body.
- It generates heat.