Skeletal Muscle Research Paper

Chapter 10 Muscle

The muscular system helps in providing the movement for bones and in doing so allows the body to make complex movements. Muscle is one of the four types of primary tissue. The three kind of muscle tissue that make up the human body are: skeletal muscle, smooth muscle, and cardiac muscle. Skeletal muscle is voluntary and are usually found attached to bones where they help to produce movement of the skeleton. Smooth muscle is involuntary and are usually found in the walls of the stomach or the urinary bladder. Cardiac muscle (only found in the heart) has to do with our heart and helps it to pump blood through our blood vessels. A total of 600 muscles is said to make up the human body. The muscle we will be talking
about the most is the skeletal muscle. Skeletal muscle is also the most abundant tissue in the body. If you don’t know about the physical characteristics of a muscle you sometimes use it’s a name for a clue. The characteristics used to name muscles are: location (e.g.
temporalis), size (e.g. Pectoralis minor where minor means small), shape (e.g. sternocleido mastoid which is v-shaped muscle), direction of fibers (e.g. rectus which goes straight), number of origins (e.g. trapezius), muscle action (Brachialis flexes the forearm), and origin and insertion (e.g. zygomaticus at zygomatic bone. Muscles come with different functions that includes: movement, maintain posture, joint stabilization and heat production. To obtain movement the muscle has to move an attached bone. Skeletal muscles are usually attached to a different bone at each end. A muscle has an origin and an insertion. The origin is point of attachment that is not moveable while insertion is the point of attachment that is moveable. The action of one muscle depends on what other muscles are doing. There are four category that describes muscle action: prime mover, antagonist, synergist, and fixator. The prime mover is the muscle takes the most responsibility in any particular joint action. An antagonist is a muscle that reverses or opposes a prime mover. A synergist is a muscle responsible for aiding the prime mover and helps in stabilizing a joint. A fixator is a muscle that stabilizes a
bone and prevents it from moving. A skeletal muscle also contains connective tissue that helps to form a single muscle. The three layers of connective tissue associated with a muscle is endomysium, perimysium, and epimysium.
Endomysium is a thin sheet of areolar connective tissue that surrounds each muscle fiber. Perimysium is a thicker sheet of connective tissue that surrounds a bundle of muscle fibers called fascicle. Epimysium is collagenous, dense connective tissue that surrounds an entire muscle. A tendon is a dense regular connective tissue, it may connect to a bone that’s moveable for the origin and to an immoveable bone to establish insertion we call a muscle that is very wide aponeurosis. There are different patterns of arrangement for fascicles, they are: parallel (and fusiform), triangular (convergent), pennate and circular. With parallel (and fusiform) the fibers are parallel to the long axis and the middle is usually thick because of the parallel muscles when they contract. Triangular (convergent) muscles are fan- shaped. The muscle fibers are being pulled in opposite directions depending on what type of stimulation occurred. Pennate muscles are feather like and are not able to move as far as parallel tendons. Pennate muscle has three types of muscle associated with it: unipennate (fascicles that enter from 1 side of the tendon), Bipennate (fascicles enters on both sides of the tendon), and multipennate (the
tendon begins to branch within the muscle).