Muscle Contraction

What must occur first before a muscle can contract?

• An action potential must develop as energy/nutrients is gained from the digestive system

• An action potential must travel to the muscle through the circulatory system

• An action potential must enter the body through the respiratory system

• An action potential must be sent through neurons in the nervous system

What neurotransmitter is used at the neuromuscular junction that sends a signal from the motor neuron to the skeletal muscle?

• Glutamate

• Acetylcholine

• Norepinephrine

• Dopamine

What happens when the action potential reaches the axon terminal of a motor neuron?

• Voltage-gated channels open, releasing sodium

• Voltage-gated channels open, releasing acetylcholinesterase

• Voltage-gated channels open, releasing acetylcholine

• Voltage-gated channels open, releasing calcium

What do calcium ions do once they are released?

• Calcium enters the muscle tissue

• Cause sodium ions to enter the muscle

• Cause potassium ions to exit the muscle

• Cause acetylcholine to be released

What is the function of acetylcholine?

• ACh binds to receptors on the sarcolemma and opens ion channels

• ACh binds to receptors on the sarcolemma and closes ion channels

• ACh binds to ion channels and open them

• ACh binds to ion channels and closes them

What ions are transported by the activated ion channel in muscle cells?

• Sodium ions rush out of the cell, while potassium ions rush into the cell

• Calcium ions rush out of the cell, while potassium ions rush into the cell

• Sodium ions rush into the cell, while potassium ions rush out of the cell

• Calcium ions rush into the cell, while potassium ions rush out of the cell

What is the purpose of the sodium potassium ion channel?

• Create an action potential

• Cause contraction

• Create a membrane potential

• Cause the release of ATP

The impulse/membrane potential caused by the ion channels affects what in the muscle cell?

• The impulse releases more ACh

• The impulse releases more calcium

• The impulse releases ATP

• The impulses releases ADP

Calcium inside the muscle cell binds to which filament, causing a shape change and revealing the active sites.

• Actin

• Myosin

• Troponin

• Tropomyosin

What binds to the active site on actin?

• Actin

• Myosin

• Troponin

• Tropomyosin