Muscle Contraction Mechanisms and Components

What molecule do our cells use to get and store energy from the food we eat?

• Glucose

• Water

• ATP

• Oxygen

Which of the following are the three main types of muscle found in the human body?

• Cardiac, Smooth, and Voluntary

• Cardiac, Smooth, and Skeletal

• Tendon, Ligament, and Bone

• Biceps, Triceps, and Quadriceps

What type of connective tissue attaches muscles to bones?

• Ligaments

• Cartilage

• Tendons

• Joints

What are the individual cells that make up muscle tissue called?

• Myofibrils

• Sarcomeres

• Muscle Fibers

• Myofilaments

Before the 1950s, what was the common belief about how protein strands in muscles caused contraction?

• They slid past each other.

• They changed shape and shortened.

• They released calcium ions.

• They were pulled by motor neurons.

What is the main mechanism of muscle contraction according to the sliding filament model?

• Protein strands change their length.

• Thick and thin filaments slide past each other.

• Muscles expand due to water absorption.

• Nerve impulses directly shorten muscle fibers.

What molecule's energy is stored in the myosin heads and then released to pull the actin filaments during muscle contraction?

• Calcium ions

• Troponin

• ATP

• Neurotransmitters

What is required for the myosin head to detach from the actin filament, allowing the muscle to relax?

• Release of calcium ions

• Binding of troponin

• A new ATP molecule

• A nerve impulse