Muscular System Histology and Physiology

Vocabulary flashcards based on key concepts from the lecture on Muscular System Histology and Physiology.

Skeletal Muscle

Responsible for locomotion, facial expressions, posture, respiratory movements, and other types of body movement; voluntary and controlled by the nervous system.

Smooth Muscle

Located in walls of hollow organs, blood vessels, eye, glands, and skin; functions involuntarily in actions such as propelling urine and regulating blood flow.

Cardiac Muscle

Found in the heart; autorhythmic and involuntarily controlled, responsible for pumping blood.

Contractility

The ability of a muscle to shorten with force.

Excitability

The capability of muscle to respond to a stimulus (usually from nerves).

Extensibility

The ability of muscles to be stretched beyond their normal resting length and still contract.

Elasticity

The ability of muscle to recoil to its original resting length after being stretched.

Epimysium

Connective tissue that surrounds an entire muscle.

Perimysium

Connective tissue surrounding a group of muscle fibers; a passage for blood vessels and nerves.

Endomysium

Connective tissue surrounding individual muscle fibers within each fascicle.

T tubules

Inward folds of the sarcolemma that project into the interior of muscle cells.

Sarcoplasmic Reticulum (SR)

Specialized smooth endoplasmic reticulum that stores calcium in muscle cells.

Sarcomere

The basic functional unit of a muscle fiber; smallest part that can contract.

Actin myofilament

Thin protein filaments in muscle fibers; involved in muscle contraction.

Myosin myofilament

Thick protein filaments in muscle fibers; involved in muscle contraction.

Neuromuscular Junction

The synapse or junction of the axon terminal of a motor neuron with a muscle fiber.

Sliding Filament Model

Describes how actin myofilaments slide over myosin filaments to shorten sarcomeres during muscle contraction.

Action Potential

A rapid rise and subsequent fall in voltage or membrane potential across a cellular membrane that propagates along the nerve cell.

Motor Unit

A single motor neuron and all muscle fibers it innervates; causes contraction in all fibers when an action potential occurs.

Isometric Contraction

Muscle contraction without a change in length, but tension increases.

Isotonic Contraction

Muscle contraction involving a change in length while tension remains constant.

Duchenne Muscular Dystrophy (DMD)

A genetic disorder leading to progressive muscle degeneration and weakness.

Hypertrophy

Increase in muscle size due to growth in fiber size.

Atrophy

Decrease in muscle size due to loss of muscle fibers or their contents.

Skeletal Muscle

Responsible for locomotion, facial expressions, posture, respiratory movements, and other body movements; under voluntary control.

Smooth Muscle

Muscle found in walls of hollow organs and blood vessels; under involuntary control and can be autorhythmic.

Cardiac Muscle

Muscle of the heart, autorhythmic, and controlled involuntarily by the endocrine and autonomic nervous systems.

Contractility

The ability of a muscle to shorten with force.

Excitability

The capacity of muscle to respond to a stimulus, usually from nerves.

Extensibility

The ability of a muscle to be stretched beyond its normal resting length and still contract.

Elasticity

The ability of muscle to recoil to its original resting length after stretching.

Epimysium

Connective tissue that surrounds a whole muscle.

Perimysium

Loose connective tissue surrounding a group of muscle fibers; carries blood vessels and nerves.

Endomysium

Loose connective tissue separating individual muscle fibers within each fascicle.

Myofibrils

Bundles of protein filaments within muscle fibers; responsible for muscle contraction.

Sarcomere

The basic functional unit of muscle fibers; smallest part that can contract.

Neuromuscular Junction

The synapse between a motor neuron and a muscle fiber; allows for signal transmission to initiate contraction.

Action Potential

Electrical changes in a neuron or muscle cell that lead to a contraction of muscle.

T tubules

Inward folds of the sarcolemma that carry action potentials deep into the muscle fiber.

Cross-Bridge Cycle

The process by which myosin heads bind to actin, pull, and release, leading to muscle contraction.

Isometric contraction

Type of muscle contraction where the muscle length does not change while tension increases.

Isotonic contraction

Type of muscle contraction where the muscle changes length while tension remains constant.

Treppe

The phenomenon where the strength of muscle contractions increases in response to repeated stimuli.

Wave Summation

Increased muscle tension due to sustained stimulation before full relaxation occurs.

Duchenne Muscular Dystrophy

A genetic disorder characterized by progressive muscle weakness and degeneration, affecting skeletal muscle.