Sliding Filament Model and Muscle Contraction

These flashcards cover key concepts related to the sliding filament model, muscle contraction, and the neuromuscular junction.

Sliding Filament Model

Describes how thin filaments slide past thick filaments during muscle contraction without changing length.

Cross Bridge

Formed when myosin heads bind to actin, leading to muscle contraction.

Sarcomere

Functional unit of muscle fibers; Z discs pull toward the M line during contraction.

Relaxed Muscle

Characterized by Z discs being further apart and H zones being visible.

Contracted Muscle

Characterized by shortened I bands, closer Z discs, and disappearance of H zones.

Neuron Reflex Arc

Pathway that signals travel from receptor to effector.

Sensory Neuron

Also called afferent neuron; carries sensory information to the central nervous system.

Motor Neuron

Also called efferent neuron; transmits signals from the central nervous system to effectors (muscles or glands).

Action Potential

An electrical signal that rapidly spreads over long distances in a cell.

Acetylcholine (Ach)

Neurotransmitter used by motor neurons to stimulate muscle contraction.

Voluntary Motor Neurons

Somatic motor neurons that activate skeletal muscle fibers.

Neuromuscular Junction

The site where a motor neuron axon terminal meets a muscle fiber.

End Plate Potential

Change in membrane potential that occurs when Ach binds to receptors on the muscle fiber.

Acetylcholinesterase

Enzyme that breaks down acetylcholine in the synaptic cleft to terminate the muscle contraction signal.