T3 L2: Physiology of muscle contraction

Question 1

How many Calcium ions bind to troponin C in the heart?

Answer 1

3 Calcium ions causing the troponin C to change conformation

Question 2

When does troponin I shut off?

Answer 2

When the conformational change in troponin C happens and causes troponin I to leave the F-actin groove to unmask the binding site on actin

Question 3

What is TnI a marker for?

Answer 3

Marker for total muscle breakdown

Question 4

What is Cardiac TnI a marker for?

Answer 4

A marker for myocardial infarct

Question 5

What are the 4 steps of a cross bridge cycle?

Answer 5

1. Myosin releases actin
2. Myosin head cleaves ATP
3. Myosin binds actin
4. Power stroke

Question 6

In what form is energy stored in muscles?

Answer 6

Creatine phosphorylated into creatine phosphate

Question 7

What is the function of creatine-phosphokinase (CPK)?

Answer 7

An enzyme that adds phosphate to creatine

Question 8

What is creatinine a diagnostic marker for?

Answer 8

Marker for kidney function

It’s a break down product of creatine

Question 9

What are the 2 calcium gradients that trigger contraction?

Answer 9

Influx of Ca2+ into the cell

Flow of cytosolic Ca2+ into the SR

Question 10

What is the SR?

Answer 10

Sarcoplasmic reticulum