As blood is pumped out of the heart and into the major arteries leaving the heart, it
A. pushes against the semilunar valves and opens them.
B. pushes against the semilunar valves and closes them.
C. fills the cusps of the semilunar valves, causing them to expand and block the backflow of blood
D. pushes against the atrioventricular valves and opens them.
E. fills the cusps of the atrioventricular valve causing opening of the bicuspid and closure of the tricuspid.
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Question 2) Cardiac muscle is able to use a variety of fuel types for cellular respiration.
Indicate whether this statement is true or false.
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Question 3) What are the cell-to-cell contacts of the cardiac muscle fibers called?
A. Z discs
B. T-tubules
C. Intercalated discs
D. Cardiac discs
E. Sarcoplasmic reticulum
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Question 4) Myofibrils within cardiac muscle cells are aligned in sarcomeres.
Indicate whether this statement is true or false.
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Question 5) The metabolic pathways of cardiac muscle make it
A.
somewhat susceptible to heart attack, because it relies so exclusively on aerobic metabolism.
B.
extremely susceptible to heart attack, because it uses such a variety of fuel sources.
C.
somewhat susceptible to heart attack, because it has so few mitochondria.
D. relatively resistant to heart attack, because it uses exclusively anaerobic metabolism.
E. relatively resistant to heart attack, because it has a great capacity to accrue oxygen debt.
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Question 6) Contrast the length-tension relationship for cardiac muscle to that which is found in skeletal muscle. In other words, for each type of muscle, what is the optimal length? How is such an arrangement adaptive to cardiac muscle?
What will be an ideal response?
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Question 7) The internal wall surface of each ventricle displays large, smooth, irregular muscular ridges called
A. conus arteriosus.
B. atrioventricular opening.
C. trabeculae carneae.
D. tendinous cords.
E. pectinate muscles.
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Question 8) Which are functions performed by the fibrous skeleton of the heart?
a: Separates the atria and ventricles
b: Anchors the heart valves
c: Provides electrical insulation between the atria and ventricles
d: Provides the framework for the attachment of the myocardium
e: None of these are true functions of the fibrous skeleton of the heart
A. a, d
B. b, d
C. a, c, d
D. a, b, c, d
E. e
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Question 9) Pectinate muscles are found on the
A. posterior wall of the right ventricle.
B. anterior wall of the right ventricle.
C. internal walls of the right and left atria.
D. posterior walls of the right and left ventricles.
E. external wall of the right atrium.
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Question 10) Typically, there are __________ papillary muscles that project from the wall of the left ventricle and attach to the tendinous cords that support the left AV valve.
A. three
B. two
C. a highly variable number of
D. six
E. no
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