Skeletal Muscle Medium

Question 1

How do calcium ions help in muscle contraction?

Answer 1

They bind to troponin, causing tropomyosin to move and expose active sites on actin.

Question 2

What happens during the power stroke?

Answer 2

The myosin head pivots, pulling actin filaments toward the center of the sarcomere.

Question 3

What causes the cross-bridge to detach?

Answer 3

ATP binds to the myosin head, causing it to release the actin filament.

Question 4

What happens when the motor neuron stops signaling?

Answer 4

Calcium channels close, and tropomyosin blocks active sites, stopping muscle contraction.

Question 5

What is a small motor unit responsible for?

Answer 5

Fine movements (e.g., eye, fingers, face).

Question 6

What is a large motor unit responsible for?

Answer 6

Gross movements (e.g., thigh, back).

Question 7

What two molecules are produced when ATP is hydrolyzed?

Answer 7

ADP and inorganic phosphate (P).