Muscular System Anatomy
The muscular anatomy drive movement of the human body. These muscles is a separate organ built of skeletal muscle tissue, blood vessels, tendons, and nerves. Muscle tissue also found inside of the heart, digestive organs, and blood vessels it’s responsible for moving substances throughout the body.
There are three types of muscle tissue: Visceral, cardiac and skeletal.
Visceral Muscle Tissue:
Visceral muscle tissue is found inside of organs like the intestines, stomach and blood vessels. It makes organs contract for moving substances through the organ. Visceral muscle is also known as involuntary muscle as it’s controlled by the unconscious part of the brain.
Cardiac Muscle Tissue:
This muscle found only in the heart, it’s responsible for pumping blood throughout the body. It is also an involuntary muscle as can’t be control by conscious mind. Cardiac muscle are auto-rhythmic or intrinsically controlled.
Skeletal Muscle Tissue:
Skeletal muscle is voluntary muscle tissue and controlled consciously by mind. Every physical action that a person consciously performs (e.g. walking, talking, etc.) requires skeletal muscle. Skeletal muscles are attached to two bones across a joint. Most skeletal muscles are attached to two bones via tendons. Tendons are very strong and are knit into the coverings of both muscles and bones.
Sarcomere (Protein Fibers)
Sarcomere is the most basic unit that makes up skeletal muscle. It’s made of two types of protein fibers: thick filaments and thin filaments.
- Thick filaments: They are made of the protein myosin. Myosin is the protein that causes muscles to contract
- Thin filaments. They are made of three proteins as Actin, Tropomyosin and Troponin.
- Actin makes up the bulk of the thin filament mass. It contains myosin-binding sites, it allow myosin to connect and move actin during muscle contraction.
- Tropomyosin is a long protein fiber that cover around actin and also covers the myosin binding sites on actin.
- Troponin are bound very tightly to tropomyosin, troponin moves tropomyosin aside from myosin binding sites during muscle contraction
Skeletal muscle fibers
It can be divided into two types based on the nature of they made and use energy i.e. Type I and Type II.
- Type I: fibers are very slow and calculated in their contractions. They are very resistant to fatigue because they use aerobic respiration i.e. the process by which oxygen turn fuel, such as fats and sugars, into energy. Type I fibers in muscles is in every part of body for stamina and posture.
- Type II: fibers split into two subgroups: Type II A and Type II B
- Type II A: fibers are faster and stronger than Type I fibers, but lack much endurance. It is found throughout the body particularly in legs
- Type II B: fibers are faster and stronger compare to Type II A and lack more endurance. It is found throughout the body particularly in upper body