It’s time to revisit your high-school anatomy class. Today’s class is about the different types of muscle tissue.
Muscles are made up of soft tissues that form together in patterns to create different types of muscles. Muscles are either voluntary or involuntary and perform different functions depending on the muscle tissue type.
The exception to this rule of being voluntary or involuntary is the diaphragm. It is different as it both acts on its own (involuntary) to control breathing (you don’t have to think about breathing), but you can also move it yourself and control the rate of breathing by moving it (voluntary).
Muscles typically work in pairs by counteracting each other’s movements. If you are curling your arms up, your biceps are contracting and your triceps are relaxing. If you are doing a pushup, your chest muscles are contracting and your upper back muscles are relaxing. Without this symbiotic relationship, you would not be able to move. If both antagonizing muscles were contracting at the same time, we wouldn’t be able to move our bodies.
There are three types of muscle tissues and all of them are different because of the functions they perform. The three types of muscle tissue are skeletal, cardiac and smooth.
Skeletal Muscle Tissue
Skeletal muscles are those attached to the skeleton and control body movements and keep the body in position. There are exceptions to this rule such as the tongue and diaphragm not being attached to the skeleton. Skeletal muscles can usually be arranged into four categories:
- Flexor, a muscle to bend a joint
- Extensor, a muscle to straighten a joint
- Abductor, a muscle to move a body part away from the bodies centerline
- Adductor, a muscle to move a body part towards the bodies centerline
Cardiac Muscle Tissue
Cardiac muscles are those found in the heart and associated respiratory muscles. Cardiac muscle is designed to contract many times over a certain lifespan. The muscle cells themselves are designed much like skeletal muscle to be very strong and are also joined to one another in a linear fashion.
However, unlike skeletal muscles, cardiac muscle fibers branch out and communicate with each other through electrical impulses. These electrical impulses are carried between each muscle by an intercalated disc to ensure communication is maintained with the nervous system and brain. The overall goal of cardiac muscles is to ensure blood gets around the body.
Smooth Muscle Tissue
Finally, we have smooth muscle tissue. Examples of where you can find smooth muscle tissue are in the internal organs, blood vessels, and the eyes. Where cardiac muscles are built for a high volume of strong contractions, smooth muscle tissue is built for slow and prolonged contraction. Smooth muscles are typically arranged in layers and vary in size to a huge extent. They normally make up muscles that react to involuntary movements.
Because muscles have different jobs to do and are put under different kinds of stress, the human body adapts to this by having these different types of muscle tissue. How the cells are arranged and how they react to different stimuli (electrical, hormonal or autonomic) show how the different types of muscle tissue become suitable for different jobs.