Muscular_system_7.

Epimysium

The fascia that surrounds muscles.

Perimysium

Connective tissue that surrounds muscle fasciculi.

Endomysium

Connective tissue that surrounds individual muscle fibers.

Action Potential

A localized change in membrane potential that propagates along nerve or muscle fibers.

Synapse

The junction between a nerve and a muscle, allowing for communication and signal transmission.

Neuromuscular Junction (NMJ)

The synapse connection between a motor neuron and a muscle fiber.

Sarcoplasmic Reticulum

The specialized endoplasmic reticulum in muscle cells that stores calcium ions.

Cross-Bridge Cycle

The process by which myosin heads interact with actin filaments to cause muscle contraction.

Calcium Ions (Ca2+)

Ions that play a crucial role in muscle contraction by binding to troponin.

Muscle Twitch

A single, brief contraction of a muscle fiber in response to a stimulus.

Isometric Contraction

A type of muscle contraction where muscle length remains the same while tension increases.

Isotonic Contraction

A type of muscle contraction where muscle changes length while maintaining constant tension.

Treppe

A graded response where subsequent contractions are stronger due to higher calcium levels in the sarcoplasm.

Fatigue

Decreased capacity to work and reduced performance efficiency, often due to ATP depletion.

Acetylcholine (ACh)

A neurotransmitter released at the neuromuscular junction that stimulates muscle contraction.

Troponin

A protein that binds Ca2+ and moves tropomyosin to expose active sites on actin.

All-or-None Principle

The concept that muscle fibers contract fully or not at all in response to a stimulus.

Motor Unit

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

Skeletal Muscle

Striated muscle that is under voluntary control and allows for movement of the skeleton.

Smooth Muscle

Non-striated muscle that controls involuntary movements within the body.

Cardiac Muscle

Striated muscle found only in the heart that is involuntary and autorhythmic.

Oxygen Debt

The amount of oxygen required to restore normal conditions after exercise.

Acetylcholinesterase

An enzyme that breaks down acetylcholine in the synaptic cleft to terminate the signal.

Rigor Mortis

The stiffening of muscles after death due to calcium ions binding to myosin heads.