Skeletal Muscles

Flashcards related to skeletal muscle structure, function, and physiology.

Skeletal Muscle

A type of muscle tissue that has the strongest fibers, is voluntary, and connects to bones to create movement.

Smooth Muscle

Involuntary muscle found in the walls of hollow organs, which is not striated and smaller in size.

Cardiac Muscle

Involuntary muscle in the heart that is striated, multi-nucleated, and connected by intercalated discs.

Epimysium

The outer layer of connective tissue that surrounds and holds together an entire muscle.

Tendon

A connective tissue that attaches muscle to bone.

Fascicle

A bundle of muscle fibers within a skeletal muscle.

Neuromuscular Junction

The site where a motor neuron communicates with a muscle fiber, allowing for muscle contraction.

Myoblast

Embryonic muscle cells that fuse to form muscle fibers.

Sarcomere

The smallest functional unit of muscle contraction, found between two Z-lines.

Sliding Filament Theory

The process of muscle contraction where myosin heads pull actin filaments towards the center of the sarcomere.

Actin

A thin filament protein involved in muscle contraction.

Myosin

A thick filament protein that interacts with actin to cause muscle contraction.

Motor Unit

A single motor neuron and all the muscle fibers it innervates.

Hypertrophy

An increase in muscle size due to exercise and increased myofibril size.

Atrophy

A decrease in muscle size due to disuse or lack of exercise.

M-line

The middle line of the sarcomere that anchors the thick myosin filaments.

Z-line

The boundary between two sarcomeres that anchors the thin actin filaments.

Acetylcholine (ACh)

A neurotransmitter released at the neuromuscular junction to stimulate muscle contraction.

Triad

A structure formed by a T-tubule surrounded by two terminal cisternae of the sarcoplasmic reticulum.

Cross-Bridge Formation

The attachment of a myosin head to an active site on actin during muscle contraction.

Dyspnea

Difficulty breathing, which may result from muscle atrophy or weakness.

Intramuscular Coordination

The ability of different muscle fibers to work together for efficient movement.