Skeletal Muscle and Motor Unit Structure

Which myofilament makes up the THIN filaments of muscle cells?

• actin

• myosin

• connectin

• hemoglobin

The THICK filaments found in a muscle cell are called

• actin

• myosin

The area of interconnecting actin molecules is called the

• I zone

• Z line

• M line

• A band

The neurotransmitter that signals muscle contraction is called...

• Acetylcholine

• Myosin

• Actin

• Calcium

Region where a motor neuron comes in close contact with a muscle cell.

• neurotransmitter
• muscular dystrophy
• muscle tension
• neuromuscular junction

The functional unit of the muscle cell is the: 

• Sarcomere
• Osteon
• Myofilament
• Muscle fiber

___ and ___ are regulatory proteins bound to actin. 

• Troponin and tropomyosin
• Myosin and actin
• Calcium and Oxygen
• Glycogen and hemoglobin

Skeletal Muscle contraction is initiated when the ________ sends a message to the muscle cell.  

• Muscle cell
• Neuron
• Gland
• None of the above

What is the name of the protein that covers the binding sites on actin?

• Myosin

• Tropoblasts

• Titan

• Tropomyosin

A single neuron and all the muscle fibers it stimulates make up a(n) _______.

• motor unit
• motor neuron
• axon
• neuromuscular junction