Muscle Physiology

What is the basic unit of a skeletal muscle called?

• Sarcomere

• Myofibril

• Muscle fiber

• Fascicle

What are the two main types of muscle fibers?

• Red and White fibers

• Fast-twitch and Slow-twitch fibers

• Aerobic and Anaerobic fibers

• Type I and Type IIb fibers

At the neuromuscular junction, which neurotransmitter is released to initiate muscle contraction?

• Dopamine

• Serotonin

• Acetylcholine

• GABA

Which process restores ATP in muscles during the first few seconds of intense exercise?

• Glycolysis

• Oxidative phosphorylation

• Creatine phosphate breakdown

• Fermentation

Which type of muscle fiber is primarily used during endurance activities like marathon running?

• Fast-twitch fibers

• Slow-twitch fibers

• Type IIb fibers

• White fibers

What is the term for the increase in muscle size following strength training?

• Hyperplasia

• Atrophy

• Hypertrophy

• Metaplasia

During muscle contraction, which structure shortens within the muscle fiber?

• The entire muscle fiber

• The myofibrils

• The sarcomeres

• The actin and myosin filaments

What is the primary energy source for muscle contraction under anaerobic conditions?

• Fatty acids

• Glucose

• ATP

• Creatine phosphate

Which of the following is NOT a function of skeletal muscles?

• Movement of bones

• Maintenance of posture

• Heat production

• Blood filtration

How does the body primarily remove lactic acid produced during exercise?

• It is converted back into glucose in the liver.

• It is excreted through sweat.

• It is broken down into carbon dioxide and water.

• It is stored in muscle cells for future energy use.