Skeletal Muscle

5 May 2021

Skeletal muscle is the only muscle tissue that is voluntary in the human body. Therefore, it is controlled consciously. Most skeletal muscles are attached to two bones across a joint through tendons. The role of the skeletal tissue is to contract and bring the bones closer together. In contracting either flexor or extender skeletal muscles, the bones of the body move, which allows a person to consciously perform (i.g speaking, walking, swimming or dancing).

To achieve movement in the body, skeletal muscle more often than not work in groups. The muscle that produces any movement in the body is called the agonist or prime mover. An agonist muscle is always paired with an antagonist muscle that produces the opposite movement on the same bone. 

In support of the agonist/antagonist pairing, other muscles work to balance the movement of the agonist:

- Synergists are supportive muscles that help to stabilise a movement and reduce any extraneous movement. Synergists muscles are often found in areas near the agonist/antagonist pairing and often connect to the same bones. 

Fixator muscles assist in holding the origin stable because skeletal muscles move the insertion closer or further away from the immobile origin.

- Tendons are very tough bands of dense regular connective tissue of strong collagen fibres that firmly attach muscles to bones. In a contraction of skeletal muscles, tendons come under extreme stress. To support this tension, the tendons attach to the periosteum of the bone by collagenous fibres (Sharpey fibres), which continues into the matrix of the bone. Going away from the bone, the tendons weave into a sheath that surrounds each skeletal muscle, the epimysium fascia.

- Skeletal muscle cells (fibres), like other body cells, are soft and fragile. The connective tissue that binds together creates a covering sheath called the epimysium fascia, which supports and protects the cells against contraction forces. The protective sheath also houses pathways for blood vessels and nerves.

Each skeletal muscle fibre is a single cylindrical muscle cell. Within each skeletal muscle, hundreds or even thousands of muscles fibres; bundled together and wrapped in a sheath of connective tissue, the epimysium fascia. Parts of the epimysium project inward to divide the skeletal muscle fibres into compartments. Each of the muscle fibre compartments is called a fasciculus that is surrounded by a layer of connective tissue called the perimysium. Each muscle fibre in each fasciculus is surrounded by a sheath of connective tissue called the endomysium.

Skeletal muscles

Skeletal muscles