21.3B Total D

What is unique about cardiac muscle cells compared to skeletal muscle cells?

• They are larger
• They have multiple nuclei
• They have 1-2 nuclei
• They lack striations

What are the protein components involved in muscle contraction?

• Collagen and elastin
• Myosin and collagen
• Actin and elastin
• Myosin and actin

What are the basic units in skeletal muscle fibers called?

• Myofibrils
• Sarcomeres
• Striations
• Filaments

How do muscles produce movement?

• By expanding
• By contracting
• By stretching
• By rotating

What is the sliding-filament model related to?

• Joint movement
• Bone growth
• Muscle contraction
• Nerve conduction

Why can muscles both push and pull?

• Because they have multiple nuclei
• Because they work in opposing pairs
• Because they have striations
• Because they are stretchable

Which muscle type can function without direct nervous system stimulation?

• Skeletal muscle
• Cardiac muscle
• Both A and B
• Smooth muscle

What type of joint exists between vertebrae in the spine?

• Freely movable joint
• Immovable joint
• Slightly movable joint
• Fixed joint

During muscle contraction, what happens to the sarcomere?

• It lengthens
• It stays the same length
• The distance between ends decreases
• It dissolves

What forms between myosin and actin during muscle contraction?

• Striations
• Cross-bridges
• Nuclei
• Sarcomeres