Muscle contraction physiology

What is the contractile unit of the muscle?

• Z disk

• Sarcomere

• Muscle fiber

• Muscle cell

What protein makes up the thick filaments?

• Troponin

• Tropomyosin

• Myosin

• Actin

What is the name of the location where the neuron and muscle fiber meet?

• Sarcoplasm

• Sacolemma

• Neuromuscular junction

• Axon terminal

Vesicles in the motor neuron store what substance?

• cholinsterase

• acetylcholine

• calcium

• curare

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.

Name the structure labeled #1 in diagram.

• endomysium

• epimysium

• perimysium

• myofibril

Name the structure labeled #5 in diagram.

• endomysium

• epimysium

• perimysium

• myofibril

Name the structure labeled #3 in diagram.

• endomysium

• epimysium

• perimysium

• myofibril

Binding sites on actin form cross-bridges with molecules of:

• Troponin

• ATP

• Tropomyosin

• Myosin

In order for an active site on actin to be exposed for the cross-bridging binding, the presence of _______ is required

• Potassium

• Sodium

• Calcium

• Water