Muscular System Review

This set of flashcards covers key terms and concepts related to the muscular system and muscle contraction mechanisms.

Neuromuscular Junction

The meeting point between a motor neuron and a muscle fiber.

Acetylcholine

The neurotransmitter released at the neuromuscular junction that binds to receptors on the muscle fiber.

Skeletal Muscle Cell

Also referred to as a muscle fiber; the basic unit of muscle tissue.

Myofilaments

Specialized contractile proteins in muscle fibers, consisting of thin (actin) and thick (myosin) filaments.

T Tubules

Extensions of the muscle cell membrane that penetrate into the cell, facilitating the transmission of electrical signals.

Sarcoplasmic Reticulum

An organelle in muscle cells responsible for storing calcium ions.

Calcium

An ion that is crucial for muscle contraction, released from the sarcoplasmic reticulum.

Troponin

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

Crossbridge Cycle

The series of events in muscle contraction involving the interaction between actin and myosin.

Action Potential

An electrical signal that triggers muscle contraction through rapid depolarization.

Creatine Phosphate

A high-energy compound used for quick ATP production during short bursts of activity.

Oxidative Metabolism

A process that requires oxygen to produce ATP through electron transport chain, providing long-term energy.

Slow Twitch Muscle Fibers

Muscle fibers optimized for endurance, utilizing oxidative metabolism and appearing darker due to abundant mitochondria.

Fast Twitch Muscle Fibers

Muscle fibers geared for quick, powerful contractions, but fatigue quickly, typically using anaerobic metabolism.

Motor Unit

A motor neuron and all the muscle fibers it innervates.

Z Disc

The boundary structure of a sarcomere where actin filaments are anchored.

Sarcromere

The basic functional unit of muscle contraction, defined as the region between two Z discs.

Voltage-Gated Sodium Channels

Ion channels that open in response to changes in membrane voltage, allowing sodium to enter the cell.

Ligand-Gated Channels

Ion channels that open when a specific chemical messenger (ligand) binds to them.