Linda's father suffers an apparent heart attack and is rushed to the emergency room of the local hospital. The doctor on call tells her that he has ordered some blood work and that he will be able to tell if her father actually had a heart attack by looking at the blood levels of CK and cardiac troponin. Why would knowing the level of CK and cardiac troponin help to indicate if a person suffered a heart attack?

Which of the following energy sources would provide the majority of the ATP for a person running a 26-mile marathon?

a. Stored ATP

b. Glycolytic catabolism

c. Oxidative catabolism

d. Creatine phosphate

Mark the following statements as true or false. If a statement is false, correct it to make a true statement.

Stimulation by a motor neuron before a muscle fiber has fully relaxed results in a condition called wave summation.

Mark the following statements as true or false. If a statement is false, correct it to make a true statement.

A muscle fiber changes length during isotonic concentric and isotonic eccentric contractions.

Tell where each of the three types of muscle tissue would be found in the body. What is meant by the statement, 'Smooth muscles are involuntary in action'?

Describe the events that occur from the time calcium ions enter the axon terminal at the neuromuscular junction until muscle cell contraction occurs.

After ACh attaches to its receptors at the neuromuscular junction, what is the next step?

a. Sodium channels open

b. Calcium binds to regulatory proteins on the thin filaments

c. Cross bridges attach

d. ATP is hydrolyzed

Chemical A binds and blocks acetylcholine receptors of muscle cells. Chemical B floods the cytoplasm of muscle cells with calcium ions. Which chemical would make the best muscle relaxant, and why?

What structural feature of a skeletal muscle fiber propagates action potentials into the interior of the cell?