Muscle System - Anatomy

Musculoskeletal system

An integrated system of bones, muscles, and joints.

Myology

The scientific study of muscle.

Excitability

The ability of muscle to send electrical waves.

Elasticity

The ability of muscle to recoil back to its original length.

Extensibility

The ability of muscle to stretch.

Contractility

The ability of muscle to pull on points with force.

Skeletal muscle tissue

Muscle attached to bones, characterized by striations, voluntary control, and limited regeneration.

Cardiac muscle tissue

Muscle that makes up the heart wall, is striated, involuntary, and can regenerate under certain conditions.

Smooth muscle tissue

Muscle found in the walls of hollow organs, non-striated, involuntary, and can regenerate.

Functions of muscular tissue

1. Producing body movement 2. Stabilizing body position 3. Regulating organ volume 4. Moving substances within the body 5. Producing heat.

Fascia

A sheet or band of fibrous connective tissue beneath the skin or around muscles and organs.

Epimysium

Tissue that surrounds the entire muscle.

Perimysium

Tissue that surrounds 10-100 muscle fibers called fascicles.

Endomysium

Tissue that surrounds each muscle fiber.

Neuromuscular Junction (NMJ)

The connection between a motor neuron and a muscle fiber, where the signal for contraction is transmitted.

Acetylcholine (ACh)

A neurotransmitter released at the NMJ that activates muscle contraction.

Rigor Mortis

Stiffening of muscles after death due to leakage of calcium and lack of ATP.

Muscle atrophy

Progressive loss of myofibrils due to disuse or denervation.

Muscle hypertrophy

Increase in muscle size due to production of more myofibrils.

Muscle tone

The continuous and passive partial contraction of the muscles.

Creatine phosphate

A molecule that provides quick energy to regenerate ATP in muscle cells for short bursts of activity.

Glycolysis

A metabolic process that converts glucose to pyruvic acid, generating ATP without oxygen.

Aerobic cellular respiration

A process that uses oxygen to produce ATP from pyruvic acid in the mitochondria.

Oxygen debt

The amount of oxygen required after physical activity to restore the body to its resting state.

Twitch contraction

A single contraction and relaxation cycle of muscle fibers.

Wave summation

A phenomenon where subsequent stimuli produce a stronger contraction due to incomplete relaxation between stimuli.

Slow oxidative fibers (SO)

Muscle fibers that are small, red, and resistant to fatigue, suited for prolonged contractions.

Fast glycolytic fibers (FG)

White muscle fibers that are powerful, rapid in contraction, but fatigue quickly.

Isometric contraction

Muscle contractions that do not change length but increase tension.

Isotonic contraction

Contractions that change the length of the muscle while maintaining tension.

Origin

The stationary attachment point of a muscle to a bone.

Insertion

The movable attachment point of a muscle.

Intercalated discs

Specialized connections between cardiac muscle cells that facilitate synchronized contractions.

Visceral smooth muscle

Type of smooth muscle found in sheets that contract in unison.

Multiunit smooth muscle

Type of smooth muscle that contracts one fiber only, controlled by its own neuron.