Muscles, Part 2

What is the primary function of skeletal muscles as commonly perceived?

• To regulate body temperature

• To perform delicate tasks

• For heavy lifting and brute-force tasks

• To provide structural support only

Muscles can only perform which type of action on bones?

• Pull

• Push

• Twist

• Extend

What is a motor unit in the context of muscle fibers?

• A single muscle fiber and its motor neuron

• A group of muscle fibers activated by a single motor neuron

• The smallest functional unit of a muscle

• A group of muscle fibers activated by different motor neurons

What leads to the phenomenon of tetanus in muscle fibers?

• A decrease in action potential frequency

• A single, prolonged contraction without relaxation

• Multiple twitches that combine due to high frequency stimulation

• The complete relaxation of muscle fibers

What distinguishes isotonic contractions from isometric contractions?

• Isotonic contractions are weaker than isometric contractions

• Isometric contractions involve movement, whereas isotonic do not

• Isometric contractions occur without neural stimulation

• Muscle length changes in isotonic but not in isometric contractions