Skeletal Muscle Lecture Notes

These flashcards cover key terms and concepts from the chapter on skeletal muscle, suited for exam preparation.

Skeletal muscle

Attached to bones of the skeleton and is under voluntary control.

Cardiac muscle

Muscle that makes up the wall of the heart and is involuntary.

Smooth muscle

Found in the walls of internal organs, such as the digestive tract, and is involuntary.

Fascia

Thin covering of connective tissue around a muscle.

Tendon

Cord-like mass of connective tissue that connects muscle to bone.

Aponeurosis

Sheet-like mass of connective tissue that connects muscle to bone, skin, or another muscle.

Epimysium

Connective tissue that surrounds the whole muscle.

Perimysium

Connective tissue that surrounds fascicles within a muscle.

Endomysium

Connective tissue that surrounds muscle fibers (cells) within a fascicle.

Neuromuscular Junction

Site where an axon of a motor neuron and a skeletal muscle fiber interact.

Acetylcholine (ACh)

A neurotransmitter that stimulates muscle contraction.

Excitation-Contraction Coupling

The connection between muscle fiber stimulation and muscle contraction.

Sliding Filament Model

Theory explaining muscle contraction based on the sliding movement of actin and myosin filaments.

Myosin

Thick filament protein that forms cross-bridges with actin during muscle contraction.

Actin

Thin filament protein involved in muscle contraction.

Muscle fatigue

Inability to contract a muscle due to various factors, such as lactic acid accumulation.

Isotonic contraction

Type of contraction in which a muscle changes length while maintaining constant tension.

Isometric contraction

Type of contraction in which a muscle contracts without changing length.

Recruitment of Motor Units

Increase in the number of motor units activated to produce more force.

Hypertrophy

Enlargement of skeletal muscle due to exercise.

Atrophy

Decrease in size and strength of skeletal muscle due to lack of use.

Multi-unit Smooth Muscle

Cells function as separate units, found in structures like the iris of the eye.

Visceral Smooth Muscle

Muscle that responds as a unit, exhibits rhythmicity, and is found in hollow organs.

Cardiac Muscle

Striated muscle located only in the heart, characterized by intercalated discs.