Respiratory Physiology 579
- Erythropoietin is produced by
a. the kidneys. c. the lungs.
b. the liver. d. the bone marrow.
- The affinity of hemoglobin for oxygen is decreased under
conditions of
a. acidosis.
b. f e v e r.
c. anemia.
d. acclimatization to a high altitude.
e. all of these.
- Most of the carbon dioxide in the blood is carried in the
form of
a. dissolved CO 2.
b. carbaminohemoglobin.
c. bicarbonate.
d. carboxyhemoglobin.
- The bicarbonate concentration of the blood would be
decreased during
a. metabolic acidosis.
b. respiratory acidosis.
c. metabolic alkalosis.
d. respiratory alkalosis.
- The chemoreceptors in the medulla are directly stimulated by
a. CO 2 from the blood.
b. H^1 from the blood.
c. H^1 in brain interstitial fluid that is derived from blood CO 2.
d. decreased arterial P^ O 2.
- The rhythmic control of breathing is produced by the activity
of inspiratory and expiratory neurons in
a. the medulla oblongata.
b. the apneustic center of the pons.
c. the pneumotaxic center of the pons.
d. the cerebral cortex.
- Which of these occur(s) during hypoxemia?
a. Increased ventilation
b. Increased production of 2,3-DPG
c. Increased production of erythropoietin
d. All of these
- During exercise, which of these statements is true?
a. The arterial percent oxyhemoglobin saturation is
decreased.
b. The venous percent oxyhemoglobin saturation is
decreased.
c. The arterial P^ CO 2 is measurably increased.
d. The arterial pH is measurably decreased.
- All of the following can bond with hemoglobin except
a. HCO^3 2
b. O 2.
c. H^1.
d. CO 2.
e. NO.
- Which of these statements about the partial pressure of
carbon dioxide is true?
a. It is higher in the alveoli than in the pulmonary arteries.
b. It is higher in the systemic arteries than in the tissues.
c. It is higher in the systemic veins than in the systemic
arteries.
d. It is higher in the pulmonary veins than in the pulmonary
arteries.
- The hypoxic ventilatory response occurs when low arterial
P^ O 2 stimulates the
a. aortic bodies.
b. carotid bodies.
c. central chemoreceptors.
d. all of these.
Test Your Understanding
- Using a flow diagram to show cause and effect, explain how
contraction of the diaphragm produces inspiration.
- Radiographic (x-ray) pictures show that the rib cage of a
person with a pneumothorax is expanded and the ribs are
farther apart. Explain why this should be so.
- Explain, using a flowchart, how a rise in blood P^ CO 2
stimulates breathing. Include both the central and peripheral
chemoreceptors in your answer.
- Explain why a person with ketoacidosis may hyperventilate.
What benefit might it provide? Also explain why this
hyperventilation can be stopped by an intravenous fluid
containing bicarbonate.
- What blood measurements can be performed to detect
(a) anemia, (b) carbon monoxide poisoning, and (c) poor
lung function?
- Explain how measurements of blood P^ CO 2 , bicarbonate, and
pH are affected by hypoventilation and hyperventilation.
- Describe the changes in ventilation that occur during
exercise. How are these changes produced and how do they
affect arterial blood gases and pH?
- How would an increase in the red blood cell content of
2,3-DPG affect the P^ O 2 of venous blood? Explain your answer.
- Describe how ventilation changes when a person goes from
sea level to a high altitude, and explain how this change is
produced. In what way is this change beneficial, and in what
way might it be detrimental?
- Explain the physiological changes in the blood’s ability
to transport and deliver oxygen to the tissues during the
acclimatization to high altitude, and identify the time course
required for these responses.
- Compare asthma and emphysema in terms of their characteristics
and the effects they have on pulmonary function tests.
- Explain the mechanisms involved in quiet inspiration and
in forced inspiration, and in quiet expiration and forced
expiration. What muscles are involved in each case?
