Unformatted text preview: nor B antigens, and therefore nothing to trigger an immune response from any of
the blood types.
84. C. People with Rh- blood will produce antibodies in response to exposure to Rh antigens.
Therefore, an Rh- mother, with previous exposure to Rh antigens will have Rh antibodies. If
she is carrying an Rh+ child, her immune system will attack the Rh antigens in her child’s
blood stream resulting in erythroblastosis fetalis.
85. C. Alleles are different forms of a gene at the same locus. They are located on homologous
86. D. One would never expect to find A and B antibodies because both the A and B proteins are
present in a person of blood type AB.
87. C. The P wave represents the first stage of the cardiac cycle, atrial contraction.
88. C. The “lub” sound in the “lub-dup” of a heart beat is caused by blood being forces against
the closed atrioventricle valve, during ventricle systole. Page 10 of 12 89. A. The walls of the ventricles would be thicker than the wall of the atria because wall
thickness is a measure of muscle strength. Since the ventricles are responsible for the power
stroke or high stroke volume.
90. D. The wall of the left ventricle would be expected to be thicker than the right ventricle
because the blood pressure entering the aorta (from the left ventricle) is higher than the blood
pressure entering the pulmonary artery (from the right ventricle). The pressure must be
higher in the aorta because that blood must travel further, around the systemic circulatory
system than the blood flowing into the pulmonary artery, around the respiratory circulatory
91. A. According to Figure 2, the pulmonary and aortic valves are open during the third phase of
the cardiac cycle, systole and a rise and fall in aortic pressure. The opening of these valves is
associated with a drop in left ventricular stroke volume but not a rise in stroke volume.
92. A. The depolarization of the atria (P wave) takes place as electrical charges initiated at...
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