Chapter 9: The Sliding Filament Model

Question 1

The sliding filament model

Answer 1

the contraction system, which shortens the muscle cell

Question 2

resting membrane potential

Answer 2

Na+ is higher outside the cell and K+ is higher inside the cell. K+ moves out of the cell faster than Na+ moves into the cell causing a negative charge. The sodium-potassium pump equalizes this polarization.

Question 3

depolarization

Answer 3

Inside of plasma membrane becomes less negative. If change reaches threshold, depolarization occurs.

Question 4

repolarization

Answer 4

return of resting potential. During this time, the polarization drops lower than its original resting potential.

Question 5

Action potential propogation

Question 6

acetylcholine ACh

Answer 6

the neurotransmitter that…

Question 7

acetelcholinesterase

Answer 7

The enzyme that breaks the bond of ACh from the bond so that it doesn’t accumulate in the muscle cell.

Question 8

cross bridge movement

Question 9

troponin

Question 10

Describe the steps of action potential propogation.

Answer 10

1) In the sarcolemma, an action potential is produced from the neuromuscular junction.

2) The action potential cuases gates in the sarcoplasmic reticulum to open causing Ca+ to flood (diffuse) into the sarcoplasm and surround the myofibrils.

3) Ca+ binds to troponin proteins that cause the tropomyosin to move and expose binding sites for the myosin heads

Question 11

What three ATP-required events are required for muscle relaxation?

Answer 11

1) The Na+-K+ pumps must actively transport the ions back to return and maintain resting membrane potential.

2) ATP is required to detach the myosin heads from the active sites for the recovery stroke.

3) ATP is used to transfer Ca+ back into the sarcoplasmic reticulum from the sarcoplasm.