Muscle Physiology Quiz

The segment of a myofibril that is called a sarcomere runs from _______________.

• one Z line to the next Z line
• one H zone to the next H zone
• one A band to the next A band
• one end of a skeletal muscle to the opposite end

Into what does the neuron release its neurotransmitter at the neuromuscular junction?

• motor end plate
• cytoplasm of the muscle cell
• terminal cisternae
• synapse

A motor unit is made up of _______________.

• all the muscle fibers within a given muscle
• a motor neuron and the muscle fibers it innervates
• all the neurons going into an individual section of the body
• a fascicle and a nerve

The crossbridges involved in muscle contraction are located on the ________________.

• myosin filaments
• actin filaments
• tropomyosin 
• troponin

Which of these statements is correct regarding muscle contraction?

• All motor units act together
• Muscle contraction continues for long periods after nervous stimulation ceases
• The crossbridges bind to the actin and shorten the sarcomeres
• Troponin is not needed to strengthen the contracting muscle cell.

Each muscle fiber is directly surrounded by connective tissue called the 

• perimysium
• fascia
• endomysium
• epimysium

Which of the following is not a component of a thin filament?

• actin
• myosin
• troponin
• tropomyosin

Which of the following statements concerning the role of Ca2+ in the contraction of skeletal muscle is correct?

• The mitochondria act as a store of Ca2+ for the contractile process
• Ca2+ entry across the plasma membrane is important in sustaining the contraction of skeletal muscle
• A rise in intracellular Ca2+allows actin to interact with myosin
• The tension of a skeletal muscle fibre is partly regulated by G proteins.

The functional unit of the contractile system in skeletal muscle is(are) 

• myofibrils
• cross-bridges
• sarcomeres
• Z-bands

Muscle fatigue sets in due to the nonavailability of 

• calcium
• ATP
• actin binding sites
• sodium

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NGSS.HS-LS1-7