Which of the following is most responsible for detecting an increase in systemic arterial H+ concentration?
A. the medulla of the brainstem
B. the peripheral chemoreceptors
C. the central chemoreceptors
D. the diaphragm
E. the dorsal respiratory group
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Question 2) Which of these would tend to increase ventilation?
A. lower than normal arterial PCO2
B. higher than normal arterial pH
C. breathing carbon monoxide
D. breathing air with increased PCO2
E. iron-deficiency anemia
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Question 3) If the nerves from the carotid and aortic bodies are cut, which of these would occur?
A. A decrease in arterial PO2 will no longer increase ventilation.
B. An increase in arterial PCO2 will no longer increase ventilation.
C. An increase in arterial lactic acid will inhibit ventilation.
D. An increase in arterial PCO2 will inhibit ventilation.
E. A decrease in arterial PO2 will inhibit ventilation.
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Question 4) Which of the following statements regarding control of respiration is correct?
A. A slight decrease in arterial PO2 is a stronger stimulus for increased ventilation than is a comparable decrease in arterial PCO2.
B. The most important signal for regulating ventilation is the H+ concentration of arterial blood.
C. Increased concentrations of lactic acid stimulate ventilation primarily by acting on peripheral chemoreceptors.
D. An increase in the HCO3- concentration in blood stimulates ventilation.
E. At high altitude, a decrease in PCO2 of the blood stimulates an increase in ventilation.
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Question 5) Which of these correctly describes the chloride shift?
A. In the lungs, chloride enters red blood cells in exchange for bicarbonate ions.
B. In the tissues, chloride exits red blood cells in exchange for carbonic acid.
C. In the tissues, chloride enters red blood cells in exchange for bicarbonate ions.
D. In the lungs, chloride enters red blood cells in exchange for CO2.
E. In the tissues, chloride enters red blood cells in exchange for CO2.
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Question 6) What brain center has neurons that fire mainly during inspiration and have input to the spinal motor neurons that activate the diaphragm and inspiratory intercostal muscles?
A. the ventral respiratory group of the medulla oblongata
B. the pre-Btzinger complex
C. the dorsal respiratory group of the medulla oblongata
D. the pneumotaxic center of the pons
E. the apneustic center of the pons
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Question 7) Action potentials in neurons in the inspiratory center of the medulla oblongata result in action potentials in the ________ nerves to the diaphragm, which in turn cause ________ of the muscle, resulting in a/an ________ in the volume of the thoracic cage.
A. motor; contraction; decrease
B. parasympathetic; contraction; decrease
C. sympathetic; contraction; increase
D. motor; contraction; increase
E. sympathetic; relaxation; increase
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Question 8) Which of the following are chemoreceptors?
A. hair cells in the cochlea
B. receptors in the aortic and carotid bodies
C. baroreceptors in the aortic and carotid arch
D. receptors that mediate the Hering-Breuer reflex
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Question 9) Which occurs as a result of hypoventilation?
A. the pH of the blood increases
B. levels of blood O2 increase
C. levels of blood H+ ions increase
D. alveolar CO2 decreases to near atmospheric levels
E. alveolar oxygen increases toward atmospheric levels
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Question 10) Which of the following statements regarding the transport of CO2 in blood is FALSE?
A. Some of the CO2 in blood is dissolved in plasma.
B. Some of the CO2 in blood is dissolved in the cytosol of erythrocytes.
C. Some of the CO2 in blood is bound to hemoglobin.
D. Most of the CO2 in blood is converted to another molecule.
E. Some of the CO2 in blood is converted to chloride.
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