Sliding Filament Model and Excitation Contraction Coupling

Where does the signal for muscle contraction originate?

• Spinal cord

• Muscle fiber

• Sarcoplasmic reticulum

• Brain

What is the name of the connection between a neuron and a muscle cell?

• Synapse

• Axon terminal

• Neuromuscular junction

• Postsynaptic cell

Which organelle stores calcium ions in a muscle cell?

• Transverse tubule

• Sarcoplasmic reticulum

• Myofibrils

• Axon terminal

What is the space between two Z lines called?

• Sarcomere

• Myofilament

• Neuron

• Synapse

What is the first step in muscle contraction?

• Release of calcium ions

• Formation of cross bridges

• Binding of neurotransmitters

• Action potential from the brain

What happens when calcium ions bind with troponin?

• Tropomyosin blocks the binding sites

• Myosin heads release and reset

• Actin and myosin filaments slide across each other

• Tropomyosin peels back, exposing the binding sites

What is the term for the myosin head binding with (or grabbing onto) the actin molecule?

• Power stroke

• Cross bridge formation

• Synaptic transmission

• Excitation contraction coupling

What is the name of the process where the myosin head pulls on the actin molecule?

• Power stroke

• Cross bridge formation

• Synaptic transmission

• Excitation contraction coupling

What happens when there is no more calcium present in the muscle cell?

• Tropomyosin blocks the binding sites

• Myosin heads release and reset

• Actin and myosin filaments slide across each other

• Muscle relaxes

What is the name of the thick filament in muscle cells?

• Actin

• Tropomyosin

• Troponin

• Myosin