Skeletal Muscle Anatomy & Physiology

These flashcards cover key concepts, terminology, and processes related to skeletal muscle anatomy and physiology.

Muscle Fiber

The basic cellular unit of skeletal muscle, responsible for contraction.

Sarcolemma

The plasma membrane of a muscle fiber.

Sarcoplasm

The cytoplasm of a muscle fiber.

Sarcoplasmic Reticulum

Smooth endoplasmic reticulum in muscle fibers that stores and releases calcium ions.

Myofibrils

The cylindrical structures within muscle fibers that contain the contractile units.

Sarcomere

The functional unit of muscle fibers, composed of actin and myosin.

Action Potential

An electrical impulse that stimulates muscle contraction by depolarizing the sarcolemma.

Neuromuscular Junction

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

Calcium Ions (Ca2+)

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

Creatine Phosphate

A molecule that helps regenerate ATP in muscle fibers during contraction.

Anaerobic Glycolysis

The process of producing ATP without oxygen, resulting in the formation of lactic acid.

Aerobic Respiration

The method of producing ATP with the use of oxygen, occurring in mitochondria.

Fast Glycolytic Fibers

Muscle fibers that generate ATP anaerobically; they fatigue quickly but provide fast contractions.

Slow Oxidative Fibers

Muscle fibers that are resistant to fatigue and generate ATP aerobically; suited for endurance.

Tropomyosin

A regulatory protein that blocks myosin binding sites on actin in relaxed muscle.

Troponin

A regulatory protein that binds calcium and causes tropomyosin to move, revealing myosin binding sites.

Muscle Fatigue

The inability of a muscle to maintain force of contraction after prolonged activity.

Repolarization

The process that returns the membrane potential to its resting state after depolarization.

Hypertrophy

The enlargement of muscle fibers, leading to muscle growth.

Acetylcholine (ACh)

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

Z Disc

The boundary of a sarcomere, anchoring the thin filaments.

M Line

The middle of the sarcomere where thick filaments are anchored.