Muscular System Part 2

What is the smallest contractile unit of a muscle?

• fasicle
• muscle fiber
• sarcomere
• myofilaments

Inside a resting muscle cell, the membrane is said to be  _______ since the outside of the membrane is more _______. 

• polarized....positive
• polarized....negative
• depolarized...positive
• depolarized....negative

The ions that are responsible for binding to troponin and unblocking the myoson binding sites on actin is _____.

• Sodium
• Calcium
• Potassium
• Magnesium

What is the name of the thick filaments?

• Actin
• Myosin
• Myoglobin
• Titan

What is the name of the thin filaments 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

When Sodium ions enter into the muscle cell, the membrane is becoming  __________.

• Repolarizing
• Depolarizing
• Electrically neutral
• none of the above

The neurotransmitter that signals muscle contraction is called...

• ACh
• Myosin
• Actin
• Calcium

Identify one factor that can cause the first sodium channel to open in a muscle cell.  

• Calcium ions being released from the sarcoplasmic reticulum.
• Acetylcholine being released from the motor neuron
• Calcium ions binding to troponin
• ATP causing the myosin heads to pop up.  

The mechanism of muscle contraction.

• sarcoplasmic reticulum
• fasciitis
• sliding filament mechanism
• muscle cramps