Chapter 13: Respiratory System Martin Caon Examination Questions and Answers in Basic Anatomy and Physiology Third Edition

Martin Caon Examination Questions and Answers in Basic Anatomy and Physiology Third Edition Chapter 13: Respiratory System 13.1 Anatomy and Physiology 1. Which of the following statements could be applied to “external respiration”? a. Exchange of gases between alveolar air and the blood in pulmonary capillaries b. Exchange of dissolved gases between blood in tissue capillaries and the body tissues c. The production of CO2 from organic molecules in the cells by using O2 d. The inhalation of atmospheric air into the lungs followed by exhalation Answer is A: External respiration refers to the movement of oxygen from the alveoli into the capillary blood and carbon dioxide from the capillary blood into the alveoli. Choice B is “internal respiration” and choice C is “cellular respiration”. 2. Which anatomical structures does the “conducting zone” of the lower respiratory tract contain? a. Eustachian tube, larynx and trachea b. Primary, secondary and tertiary bronchi and bronchioles c. Nares, conchae, olfactory mucosa and sinuses d. Nasopharynx and larynx Answer is B: The conducting zone is distal to the trachea and before the alveoli. 3. What is the function of the cilia on the cells that line the bronchial tree? a. They help mix the inhaled fresh air with the residual air contained in the bronchial tree. b. They slow the movement of air to allow for efficient exchange of gases. c. They move the mucus on the cell surface up out of the bronchial tree. d. They filter particles from inhaled air. Answer is C: The beating of the cilia moves mucus lying on the surface of the epithelium of the conducting zone, and any contained dust, up out of the bronchial tree. 4. Which one of the following statements is correct? a. The visceral pleura is attached to the chest wall, and the parietal pleura is attached to the lung. b. The two lungs and their associated structures are known as the pneumothorax. c. The hilum is a serous membrane that surrounds each lung separately. d. A negative pressure is maintained between the two lung pleura. Answer is D: The parietal pleura (attached to the chest wall) and the visceral pleura (attached to the lung) are in very close contact but “separated” by pleural fluid within which there is a pressure that is less than atmospheric pressure (i.e. negative). This means that the lungs are stuck to the chest wall and expand when it does. 5. What term is applied to the volume of air that moves into the lungs while breathing at rest? a. Anatomical dead space b. Inspiratory reserve capacity c. Tidal volume d. Residual volume Answer is C: Tidal volume moves into the lungs (and out) with each completed inhalation/exhalation at rest. 6. Severing the nerves that innervate the breathing muscles may lead rapidly to death. Will a spinal cord break between the level of cervical vertebrae 6 and 7 leave the victim able to breathe? Choose the answer with the correct reason. a. No. The breathing muscles are innervated by spinal nerves that leave the spinal cord at the level of each thoracic vertebra. b. Yes. The diaphragm will work as it is innervated by nerves arising from C3 to C5. c. No. The breathing muscles are innervated by autonomic impulses from the respiratory centre which is located in the brain stem. d. Yes. The muscles of breathing are innervated by the sympathetic nervous system which is unaffected by damage to the somatic nervous system. Answer is B: The diaphragm, but not the intercostal muscle, will still receive innervation as the diaphragmatic nerves leave the spinal cord superior to the break at C6–C7. 7. Which molecule or ion dissolved in blood is able to stimulate the central chemoreceptors of the brain’s respiratory centre? a. CO2 b. H3O+ c. O2 d. Ca2+ Answer is A: Blood-borne hydronium cannot cross the blood–brain barrier. However, carbon dioxide can and it produces hydronium ions when it is on the brain side of the BBB. As there is no buffer in the CSF, these hydronium ions stimulate the central chemoreceptors of the respiratory centre. 8. What term is applied to the exchange of dissolved gases between capillary blood and body tissues? a. Internal respiration b. External respiration c. Ventilation d. Cellular respiration Answer is A: Internal respiration refers to the movement of oxygen from the capillary blood into the tissues and carbon dioxide from the tissues into capillary blood. Choice B occurs between the alveoli and pulmonary capillaries, and choice C occurs within the mitochondria. 9. Between which two anatomical structures does the Larynx lie? a. The nares and the choanae b. The epiglottis and the trachea c. The choanae and the glottis d. The glottis and the epiglottis Answer is B: The larynx is the tube that surrounds the vocal apparatus. It consists of the epiglottis, thyroid cartilage and cricoid cartilage and is located at the top of the trachea. 10. What is the function of the ciliated cells of the respiratory epithelium? a. To trap inhaled particles not removed by the nasal cavity b. To secrete a mucus layer onto the epithelium c. To move mucus and trapped particles up the bronchial tree d. To secrete surfactant that decreases water surface tension Answer is C: Ciliated cells have cilia that beat rhythmically to move inhaled dust particles that have been caught by the mucus out of the respiratory tract. 11. Why is it that bronchioles can constrict and so reduce their diameter while secondary bronchi and respiratory bronchioles cannot constrict? a. Bronchioles have smooth muscle but no cartilage in their walls while secondary bronchi are supported by cartilage. b. Bronchioles have smooth muscle but no cartilage in their walls while respiratory bronchioles are supported by cartilage. c. Bronchioles have cartilage but no smooth muscle in their walls while secondary bronchi are supported by cartilage. d. Bronchioles have cartilage but no smooth muscle in their walls while respiratory bronchioles only have smooth muscle in their walls. Answer is A: Because bronchioles have no cartilage in their walls, they are able to dilate and constrict to alter the amount of air that enters alveoli. Respiratory bronchioles that feed into alveolar ducts have little smooth muscle and no cartilage. 12. A person with severe trauma to the cervical region has damage to the spinal cord. If the spinal cord is severed between C3 and C4, what is the likely outcome? a. The person will be able to breathe but will have paralysis of the lower limbs. b. The person will be able to breathe but will have paralysis of the upper and lower limbs. c. The person will be able to breathe with the intercostal muscles, but will lose the use of the diaphragm have paralysis of the upper and lower limbs. d. The person will be unable to breathe and will have paralysis of the upper and lower limbs. Answer is D: The diaphragm is innervated by the phrenic nerves which arise from the C3–C5 vertebrae. Hence the person will be unable to use their diaphragm (much). The upper limbs are innervated by spinal nerves that leave the spinal cord between C5 and T2, so those nerves will have been interrupted as well.