How Muscles Contract

What is the name of the thick myofilaments?

• Actin
• Myosin
• Myoglobin
• Titan

What is the name of the thin myofilaments in the muscle cell?

• Actin
• Myosin
• Myoglobin
• Titan

What is the structure that stores the calcium in the muscle cell.  

• Sarcoplasm
• Sarcolemma
• Sarcoplasmic Reticulum
• Myoglobin

The contractile unit of a muscle is called the __________.

• Sarcolemma
• Sarcoplasmic reticulum
• Sarcoplasm
• Sarcomere

Axon terminal is represented by

• 1
• 2
• 3
• 4

Number 3 represents which of the following events

• action potential reaches the axon terminal
• sodium rushes into the muscle fiber
• potassium leaving the muscle fiber
• ACh crossing the synaptic cleft

Contractions are generated by

• shortening of thick filaments
• shortening of thin filaments
• sliding of thin filaments past thick filaments
• "accordian-like" folding of thick and thin filaments

What are the two ions transported across the membrane in an action potential?

• O^2- and K⁺
• K⁺ and Na⁺
• Ca⁺² and B⁺³
• Na⁺¹ and Cl

enzyme that breaks down the muscle cell neurotransmitter and ends the impulse

• lactase
• sucrase
• lipase
• acetylcholinterase

Once calcium is released, it will

• attaches to myosin head
• attaches to receptors 
• attaches to tropomyosin
• attaches to troponin