Muscle Functions Quiz

The ability of a muscle cell to respond to stimuli by generating an electrical signal, called an action potential.

The unique ability of muscle cells to shorten and thicken, producing force.

The capacity of a muscle cell to be stretched without being damaged.

The ability of a muscle cell to return to its original shape after being stretched.

The smallest contractile unit of a muscle fiber, composed of actin (thin) and myosin (thick) filaments.

A layer of connective tissue that surrounds a single muscle fiber, providing electrical insulation.

A layer of connective tissue that surrounds a bundle of muscle fibers (fascicle), helping organize muscles.

A layer of connective tissue that surrounds the entire skeletal muscle, providing structural support and protection.

A specialized structure formed by the junction of an axon terminal with the motor end plate, responsible for transmitting nerve impulses to muscle fibers.

A network of interconnected tubules that surround the myofibrils of a muscle fiber, responsible for storing and releasing calcium ions (Ca+2) during muscle contraction.

The functional unit of a muscle fiber, consisting of a repeating sequence of protein filaments that slide past each other during muscle contraction.

A specialized type of protein found within muscles, responsible for converting chemical energy (ATP) into mechanical energy, enabling muscle contraction.

A thin protein filament found within muscles, comprised of actin, tropomyosin, and troponin, interacting with myosin to generate contraction.

A protein that binds to both dystrophin and laminin, helping to anchor the cytoskeleton of the muscle fiber to the extracellular matrix.

A protein that plays a crucial role in muscle fiber stability by linking the Z line to the sarcolemma, preventing excessive stretching.

Specialized invaginations of the sarcolemma, responsible for conducting action potentials from the surface of the muscle fiber towards the sarcoplasmic reticulum.

The process where muscle fibers shorten, generating force, involving the sliding of actin and myosin filaments past each other.

A protein that covers the active sites of actin filaments in a resting muscle fiber, preventing myosin binding.

A protein complex that binds calcium ions, triggering a conformational change in tropomyosin to expose actin's active sites.

The energy source for muscle contraction, providing the energy for myosin head movement and detaching from actin.

The binding of myosin heads to actin's active sites, forming cross bridges and initiating the power stroke.

The event where myosin heads pull actin filaments towards the center of the sarcomere, shortening the muscle fiber.

The enzyme that breaks down acetylcholine in the synaptic cleft, stopping muscle contraction.

A calcium pump located in the sarcoplasmic reticulum (SR) that actively transports calcium ions back into the SR, leading to muscle relaxation.

The initial source of energy for muscle contraction, lasting only 1-2 seconds.

The second energy source for muscle contraction, lasting 8-10 seconds.

This involves breaking down glucose or glycogen for energy, eventually entering the Kreb's cycle in the mitochondria.

The central nervous system's way to increase muscle contraction strength by activating more motor units.

The number of muscle fibers controlled by a single motor neuron.

A decrease in muscle force due to repeated stimulation.

Muscle fibers that can contract quickly and forcefully, but fatigue rapidly.

Muscle fibers that contract slowly and fatigue slowly.