Excitation/Contraction

Question 1

What protein does Myosin anchor to?

Answer 1

Titin

Question 2

Titin is important for striated muscle’s……

Answer 2

Elasticity

Question 3

Dysfunctional titin protein causes the following Cardiomyopathies?…

Answer 3

1. Dilated cardiomyopathy

2. Restrictive cardiomyopathy

Question 4

What does tropomyosin do?

Answer 4

It blocks myosin binding sites on actin

Question 5

What is necessary for tropomyosin to liberate myosin binding sites on actin?

Answer 5

For Ca++ to bind to Troponin-C

Question 6

ATP’s role on myosin-actin complex ?

Answer 6

ATP is necessary to break link between Myosin and Actin.

Question 7

Mechanism of Rigor Mortis?

Answer 7

No ATP to break Myosin - Actin cross-bridge = contraction

Question 8

What are the 2 receptors necessary for the passage of Ca++ from the SR into the cytosol ?

Answer 8

1. Dihydropyridine Receptor (DHP)

2. Ryanodine (RyR receptor )

Question 9

In order for the Ryanodine receptor to open and thus liberate Ca++ from the SR into the cytosol, what needs to happen?

Answer 9

Activation of Voltage Gated Dihydropyridine Channels —> Open Ryanodine Channels

Question 10

ATPase receptor necessary to bring Ca++ back to SR?

Answer 10

SERCA

Question 11

2 Primary characteristics necessary to increase PEAK FORCE in muscle contraction ?

Answer 11

1. Summation.

2. Recruitment

Question 12

Why can’t cardiac muscle tetanize?

Answer 12

1. Because of its long action potential (absolute refractory period)

Question 13

Main difference between striated muscle and smooth muscle ?

Answer 13

1. Smooth muscle lacks TTT’s: Troponin, Tropomyosin, and Titin.

Question 14

Main difference between Cardiac Muscle and Striated Muscle ?

Answer 14

1. Extra cellular Ca++ is involved in cardiac muscle contraction