Deck 36: Cardiac and Muscle Disease

Question 1

In which of the following situations would cTnI be elevated?

A)acute skeletal muscle injury following marathon racing
B)chronic myopathy of Duchenne muscular dystrophy
C)myocardial infarction
D)all of the above

Answer 1

myocardial infarction

Question 2

Which of the following laboratory results are seen during cardiac ischemia?

A)increased K⁺ and acidosis
B)decreased K⁺ and alkalosis
C)increased Ca²⁺ and acidosis
D)decreased Ca²⁺and alkalosis

Answer 2

increased K⁺ and acidosis

Question 3

Troponin ______ is found in cardiac and skeletal muscles and is not utilized in laboratory testing for evidence of a myocardial infarction.Although there are skeletal muscle forms of troponin ______, cardiac-specific isoforms have been identified and are the focus of laboratory testing.Only one form of troponin ______ has been identified, and it has never been found in skeletal muscle.

A)C, I, T
B)I, T, C
C)C, T, I
D)T, I, C

Answer 3

C, T, I

Question 4

Which of the following statements is true of the troponin polypeptides?

A)Troponin T binds to actin and inhibits the activity of actomyosin ATPase.
B)Troponin I is responsible for tropomyosin-binding activity.
C)Troponin C is responsible for calcium-binding activity of muscle contraction.
D)All of the above

Question 5

The first myocardial marker to elevate following the onset of MI symptoms is ______.The concern with this marker is ______.

A)cTnI, this may return to normal before a blood sample can be collected
B)CK-MB, this may return to normal before a blood sample can be collected
C)myoglobin, this marker is considered nonspecific
D)cTnT, this marker is considered nonspecific

Question 6

The most common cause of cardiac ischemia is:

A)severe anemia
B)coronary atherosclerosis
C)hypotension
D)coronary vasospasm

Question 7

Usually _________ are required after the onset of chest pain before CK-MB or the troponins become elevated in the serum of patients suffering from a myocardial infarction.

A)1 to 2 hours
B)2 to 4 hours
C)4 to 6 hours
D)6 to 8 hours

Question 8

Which of the following laboratory tests would be the most useful in assisting the physician in differentiating congestive heart failure from other conditions that have similar clinical presentations?

A)lactate
B)CK-MB
C)cTnI
D)BNP

Question 9

An increased level of which of the following analytes serves as laboratory evidence of cardiac ischemia?

A)lactate
B)CK-MB
C)cTnT
D)BNP

Question 10

The troponin complex is a set of three proteins that participate in the regulation of muscle contraction.Troponin ______ functions as the tropomyosin-binding component, troponin ______ functions as the inhibitory component, and troponin ______ functions as the calcium-binding component.

A)C, I ,T
B)I, T, C
C)C, T, I
D)T, I, C

Question 11

Troponin remains elevated in blood for how long after a myocardial infarction?

A)4 to 10 days
B)4 to 10 hours
C)3 to 7 days
D)3 to 7 hours

Question 12

The energy for muscle contraction is generated by the hydrolysis of ATP by myosin.The amount of ATP hydrolyzed during muscle contraction depends on what factors?
1)the duration of contraction
2)the strength of contraction
3)the amount of work done by the muscle

A)1, 2, 3
B)1, 2
C)2, 3
D)1, 3

Question 13

Cardiac output is determined by which of the following:

A)volume of blood pumped
B)the contractile force developed in the wall of the left ventricle
C)systemic blood pressure
D)all of the above

Question 14

Cardiac muscles use a series of enzymes to maintain a high energy reserve.The enzyme ______ functions to regenerate ATP by combining a phosphate group from an energy-reserve molecule with ADP.The enzyme ______ also ensures adequate ATP levels by combining two ADP molecules into ATP and AMP.The enzyme ______ functions to prevent accumulation of AMP in the muscle.

A)AD, CK, MK
B)CK, MK, AD
C)MK, AD, CK
D)AD, MK, CK

Question 15

The resting heart's fuel of choice is ______, but upon the imposition of a heavy workload, the heart will greatly increase its rate of ______ consumption.

A)free fatty acids, glucose
B)glucose, lactate
C)lactate, free fatty acids
D)glucose, free fatty acids

Question 16

Of the drugs used to treat cardiac muscle disease, which of the following requires the closest laboratory monitoring of drug concentration in the body?

A)lidocaine
B)digoxin
C)quinidine
D)procainamide

Question 17

Organize the following events of the acute coronary syndromes in the correct order.
1)myocardial infarction
2)angina
3)unstable angina, frequently associated with minor myocardial damage
4)extensive tissue necrosis
5)reversible tissue injury

A)3, 1, 4, 2, 5
B)1, 3, 5, 4, 2
C)2, 5, 3, 1, 4
D)4, 5, 2, 3, 1