MEH

Functions of Skeletal Muscle

Skeletal muscles enable movement, maintain posture, generate heat, support soft tissues, and protect internal organs.

Epimysium

The outermost layer of connective tissue surrounding a skeletal muscle.

Endomysium

The innermost layer of connective tissue surrounding individual muscle fibers within a skeletal muscle.

Perimysium

The connective tissue surrounding bundles of muscle fibers called fascicles within a skeletal muscle.

Tendon vs

Tendons connect muscle to bone, while ligaments connect bone to bone.

Components of a Muscle

Muscle → Fascicle → Muscle Fiber → Myofibril → Sarcomere.

Parts of a Myofibril

Myofibrils consist of sarcomeres, which are made up of thick and thin filaments.

Parts of a Sarcomere

Sarcomere includes Z-lines, I-band, A-band, H-zone, and M-line.

Steps of Contraction

Contraction involves the activation of cross-bridges between actin and myosin filaments, leading to the sliding of filaments and muscle shortening.

Neuromuscular Junction

The point of contact between a motor neuron and a muscle fiber where communication for muscle contraction occurs.

Botulism, Rigor Mortis, Tetanus

Botulism is caused by a toxin affecting neuromuscular communication, Rigor Mortis is stiffening after death, and Tetanus is sustained muscle contraction due to a bacterial toxin.

Twitch Muscle Fibers

Twitch fibers are muscle fibers that contract quickly but fatigue rapidly.

Incomplete vs

Incomplete tetanus is when muscle fibers partially relax between contractions, while complete tetanus is when contractions fuse into a sustained contraction.

Isometric vs

Isometric contractions maintain muscle length, while isotonic contractions involve muscle length changes.

Muscle Fatigue

Muscle fatigue occurs due to the accumulation of metabolic byproducts, depletion of energy reserves, and buildup of lactic acid.

Skeletal Muscle Fibers

Types include slow-twitch (Type I), fast-twitch oxidative-glycolytic (Type IIa), and fast-twitch glycolytic (Type IIb) fibers.

Origin vs

The origin is the attachment site of a muscle that remains stationary, while the insertion is the attachment site that moves during muscle contraction.

Agonist vs

Agonist is the muscle causing the primary movement, antagonist opposes the agonist, and synergist assists the agonist in performing the movement.