Muscular System - Histology

These flashcards cover key terms and definitions related to the histology and physiology of the muscular system, essential for understanding the structure and function of muscles.

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

Found in walls of hollow organs, blood vessels, eyes, glands, skin; involuntary control by endocrine and autonomic nervous systems.

Cardiac Muscle

Major source of movement of blood, found in the heart; autorhythmic and controlled involuntarily.

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 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 being stretched.

Epimysium

Connective tissue that surrounds a whole muscle.

Perimysium

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

Endomysium

Loose connective tissue separating individual muscle fibers within each fascicle.

Neuromuscular Junction

The point of contact between a motor neuron and a muscle fiber.

Action Potential

An electrical signal that stimulates muscle contraction.

Troponin

A protein complex in muscle fibers that helps regulate the interaction between actin and myosin during contraction.

Cross-Bridge

The connection formed when myosin heads bind to active sites on actin.

Sliding Filament Model

The theory that actin myofilaments slide over myosin to shorten sarcomeres during muscle contraction.

Calcium Ions (Ca²+)

Play a crucial role in muscle contraction by binding to troponin.

Sarcomere

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

Myofibrils

Bundles of protein filaments containing myofilaments that cause contraction.