Biology 232 Lecture Outline: Muscles and Muscle Tissue

A set of flashcards covering key concepts from Chapter 9: Muscles and Muscle Tissue, focusing on physiology of skeletal muscle fibers.

Neuromuscular Junction

The site where a motor neuron communicates with a muscle fiber, involving the axonal terminal and synaptic vesicles.

Acetylcholine

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

Acetylcholinesterase

An enzyme that destroys acetylcholine to stop muscle contraction.

Action Potential

A change in electrical potential that travels along the sarcolemma of muscle fibers, leading to muscle contraction.

Depolarization

The initial phase of action potential where the membrane potential becomes less negative.

Repolarization

The phase of action potential where the membrane potential returns to a negative value after depolarization.

Calcium ion (Ca2+)

An ion that, when released from the sarcoplasmic reticulum, binds to troponin to trigger muscle contraction.

Troponin

A protein that binds calcium ions and plays a key role in muscle contraction.

Sliding Filament Theory

The explanation that muscles contract by the sliding of actin and myosin filaments past each other.

Power Stroke

The action where the myosin head pivots, pulling the actin filament and causing muscle contraction.

Cross Bridge Attachment

The binding of myosin heads to active sites on actin filaments.

Cross Bridge Detachment

The release of the myosin head from the actin filament after the power stroke.

Cocking of the Myosin Head

The resetting of the myosin head to its original position using ATP.