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Respiratory system MCQs with Answers

Respiratory system

1. Anatomy is:
A. the study of the structure, shape, size and location of the
cell, tissue, organ and its parts
B. the study of how the body and its parts function
C. the study of the body and its interaction with the environment
D. All of the above are correct answers

2. Physiology is:
A. the study of the structure and shape of the body and its parts
B. the study of how the body and its parts function
C. the study of the body and its interaction with the
D. All of the above are correct

3. 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.

4. 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.

5 One of the following statements is correct. Which one?
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.

6 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

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. Ca ++

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

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

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

11 The walls of the following structures are all supported by cartilage except for one of them. Which one?
A. bronchioles
B. trachea
C. bronchi
D. larynx

12 One statement below about the larynx is correct. Which one?
A. It has walls lined with ciliated cells
B. It has walls made of cartilage
C. It has walls made of bone
D. It has walls made of muscle

13 How is the diaphragm innervated?
A. By the parasympathetic division arising from the sacral region
B. By the spinal nerves arising from T5 to T10
C. By the phrenic nerves arising from C5 to C7
D. By the phrenic nerves arising from C3 to C5

14 What mechanism transports the largest portion of oxygen around the body?
A. oxygen is carried bound to plasma proteins
B. oxygen is transported in solution dissolved in blood plasma
C. oxygen is bound to haemoglobin within red blood cells
D. oxygen is transported as bicarbonate after reacting with water to form carbonic acid

15 Which structures constitute the “upper respiratory tract”?
A. nose, pharynx and larynx
B. larynx, epiglottis and bronchi
C. trachea, bronchi and bronchioles
D. terminal bronchioles, alveoli and pleurae

16 The lists below include of four respiratory tract structures. Which list has them in the order that inhaled air would pass through them on the way to the lungs?
A. glottis, pharynx, conchae, trachea
B. nares, pharynx, larynx, conchae
C. conchae, pharynx, larynx, trachea
D. pharynx, conchae, trachea, glottis

17 What function is served by the goblet/mucus cells of the bronchial “tree”?
A. they trap small inhaled particles.
B. they secrete mucus onto the surface of the airways
C. they increase the surface area available for gas exchange.
D. they move mucus up the bronchial tree.

18 In what form is the majority of carbon dioxide that is generated by cellular respiration, transported to the lungs?
A. as dissolved carbon dioxide in the blood plasma.
B. bound to haemoglobin in red blood cells.

C. as carbonic acid inside red blood cells.
D. as bicarbonate ions in the blood plasma

19 The term “cellular respiration” is applied to:
A. exchange of gases in the lungs
B. ventilation of the lungs (breathing)
C. exchange of gases in the body tissues
D. the production of ATP in the cells

20 What happens when carbon dioxide levels in the blood decrease to below normal?
A. pH of the blood decreases.
B. the blood becomes more acidic.
C. the concentration of hydrogen ions in the blood decreases.
D. pH does not change.

21 In a healthy person, which of these lung volumes should be the largest?
A. tidal volume
B. vital capacity
C. expiratory reserve volume
D. residual volume

22 What ensures that the lungs expand as the chest wall expands?
A. secreted surfactant
B. negative pressure between the pleura
C. serous liquid secreted by the pleura
D. the elastic recoil of the alveolar tissue

23 Which of the following is responsible for increasing respiratory activity under normal conditions?
A. decreased CO 2 level in blood

B. decreased O 2 level in blood
C. increased CO2 level in blood
D. increased blood pH

24 Which structures comprise the lower respiratory tract?
A. pharynx, larynx, trachea
B. larynx, trachea, bronchi
C. nose, pharynx, larynx
D. trachea, bronchi, lungs

25 With regard to lung ventilation, what does “dead space” refer to?
A. air in the conducting zone of the bronchial tree
B. air remaining in the alveoli after an exhalation at maximal
C. air between the parietal and visceral pleura
D. the difference between the volume of a maximum inhalation and the tidal volume.

26 In red blood cells, carbonic anhydrase catalyses the formation of carbonic acid which then disassociates into bicarbonate ions and hydrogen ions. What happens next?
A. bicarbonate ions bind to haemoglobin
B. hydrogen ions move into the plasma to be buffered by bicarbonate ions
C. hydrogen ions are buffered by haemoglobin
D. chloride ions enter the rbc to form hydrochloric acid (HCl)

27 What happens when carbon dioxide levels in the blood increase?
A. pH of the blood increases.
B. the blood becomes more alkaline.
C. the number of hydrogen ions in the blood decreases.

D. the blood becomes more acidic.

28 Chemoreceptors in the medulla oblongata are sensitive to
A. increases in blood oxygen content.
B. increases in blood carbon dioxide.
C. increases in blood pH.
D. both choices A. and B.

29 What does sympathetic nervous system stimulation to the smooth muscle layers in the bronchioles cause?
A. bronchoconstriction
B. bronchodilation
C. an increase in tidal volume
D. increase in activity of the cilia

30 Which of these structures has no cartilage in it?
A. Epiglottis
B. Trachea
C. Bronchi
D. Alveoli

31 With regard to the respiratory centre, which of the following is TRUE?
A. Blood oxygen concentration affects the respiratory centre.
B. Anaesthetics don’t affect respiration.
C. Raised intracranial pressure increases ventilation.
D. Narcotic drugs may depress ventilation

32 In the control of respiration, which of the following is NOT TRUE?
A. Peripheral chemoreceptors respond to changes in oxygen and carbon dioxide concentration in the blood

B. Chemoreceptors in the central nervous system respond to changes in carbon dioxide concentration in the blood
C. Respiration responds to smaller changes in the blood concentration of oxygen than carbon dioxide
D. Central chemoreceptors are sensitive to changes in the pH of the cerebrospinal fluid

33 Gas exchange takes place in the:
A. larynx
B. bronchioles
C. alveoli
D. pleura

34 The walls of the trachea are held open by which of the following?
A. nerve impulses
B. rings of cartilage
C. fine bones
D. smooth muscle contractions

35 Oxygen and carbon dioxide cross the respiratory membrane by the process of:
A. counter-current exchange
B. diffusion
C. active transport
D. oxygen – carbon dioxide pump

36 The greatest amount of air which can be moved in and out of the respiratory system is the:
A. tidal volume
B. vital capacity
C. ventilatory volume
D. pulmonary capacity

37 A molecule that is important in maintaining normal lung structure is:
A. immunoglobulin
B. haemoglobin
C. peroxidase
D. surfactant

38 What are the main muscles involved in normal inspiration?
A. muscles of the neck
B. abdominal muscles
C. intercostal muscles
D. intercostals and the diaphragm

39 What is the number of breaths per minute called? The:
A. respiratory rate
B. respiratory speed
C. pulmonary index
D. respiratory volumel

40 A man runs up a flight of stairs. His respiratory rate rose from 18 breaths per minute (resting) to 36 bpm (at the top of stairs). The increase was probably a result of:
A. increased blood pH
B. increased concentration of CO2 in the blood
C. decreased concentration of O2 in the blood
D. decreased concentration of CO2 in the blood

41 What are the membranes that surround each lung called? The
A. parietal and visceral membranes.
B. parietal and visceral meninges
C. pleura
D. peritoneum

42. Which of the following buffer systems of the body is affected by the action of the lungs?
A. protein
B. monohydrogen-phosphate/dihydrogen-phosphate
C. ammonia/ammonium
D. carbonic acid/bicarbonate

43 If the partial pressure of oxygen in alveolar air is 100 mmHg and the concentration of dissolved oxygen in capillary blood arriving at the alveoli is 40 mmHg, what will be the concentration of dissolved oxygen in blood leaving the alveoli?
A. 140 mmHg
B. 100 mmHg
C. 70 mmHg
D. 60 mmHg

44 What does it mean if oxygenated blood leaving the alveolar capillaries has an oxygen partial pressure of 100 mmHg?
A. oxygen will have diffused from the blood into the alveoli.
B. the partial pressure of oxygen in the alveoli was 100 mmHg
C. the partial pressure of oxygen in the alveoli was less than 100 mmHg
D. the partial pressure of oxygen in the alveoli was more than 100 mmHg

45 If the partial pressure of oxygen in the atmosphere was halved, what effect would this have on the amount of oxygen that would now dissolve in the alveolar fluid? It would
A. decrease to one quarter its former value.
B. decrease to one half its former value.
C. be about the same as before.
D. increase to one and a half times its former value.

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