Muscle Contraction

Flashcards on vocabulary related to muscle contraction and physiology, including definitions of key terms and concepts.

Skeletal Muscle

Muscle that is striated and multinucleate, primarily responsible for body movement.

Smooth Muscle

Involuntary muscle that lacks striations and is mononucleate.

Cardiac Muscle

Striated muscle found only in the heart, branching structure, and mononucleate.

Excitability

Ability of muscle tissue to receive electrical signals from the nervous system and respond accordingly.

Contraction

The action of a muscle shortening by pulling both ends together.

Relaxation

The state when a muscle returns to its original state after contraction.

Troponin

A protein on the actin filament that binds calcium ions and regulates muscle contraction.

Acetylcholine (ACh)

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

Sarcomere

The functional unit of a muscle fiber, composed of actin and myosin filaments.

T-tubules

Deep indentations in the sarcolemma that allow action potentials to reach the sarcoplasmic reticulum.

Myofibril

Long threads within muscle fibers that extend the whole length of the cell, composed of sarcomeres.

Creatine Phosphate

A high-energy compound used to rapidly produce ATP for muscle contraction.

Anaerobic Glycolysis

A metabolic process that breaks down glucose without oxygen, producing ATP during short bursts of intense activity.

Aerobic Respiration

A metabolic process that uses oxygen to produce ATP efficiently in muscle cells.

Muscle Fatigue

The decline in ability of a muscle to generate force as ATP reserves are depleted.

Oxygen Debt

The amount of oxygen required to restore ATP and clear lactic acid after intense exercise.

Isotonic Contraction

Muscle contraction where the tension remains constant while the muscle shortens or lengthens.

Isometric Contraction

Muscle contraction where the muscle generates tension without changing its length.

Motor Unit

A motor neuron and all the muscle fibers it innervates, functioning together to produce movement.

Treppe

The staircase effect observed when muscle contractions increase in strength with successive stimulation.

Rigor Mortis

The rigidity of skeletal muscle that occurs after death due to the lack of ATP, preventing muscle relaxation.

Hypotonia

Reduced muscle tone, often characterized by poor reflexes, usually due to nervous system impairment.

Hypertonia

Increased muscle tone, which can lead to excessive tightening of muscles and overactive reflexes.