Deck 11: The Blood

Question 1

In the absence of pulmonary surfactant, smaller alveoli display a larger inward-directed pressure than do larger alveoli.

Answer 1

True

Question 2

Pulmonary surfactant is secreted by Type II alveolar cells.

Answer 2

True

Question 3

The inspiratory and expiratory neurons both display pacemaker activity.

Answer 3

False

Question 4

During hyperventilation, arterial P_CO2 levels decrease because CO₂ is blown off more rapidly than it is being produced in the tissues.

Question 5

Systemic arterial P_O2 is greater than tissue P_O2.

Question 6

Administering O₂ to patients with severe chronic lung disease will not depress their drive to breathe.

Question 7

The 500 mL of air that is inspired is the same 500 mL of air that enters the alveoli during a single breath.

Question 8

The partial pressure of nitrogen in the atmosphere is greater than the partial pressure of oxygen in the atmosphere.

Question 9

Exhaled air passes from the larynx through the trachea.

Question 10

Newborn respiratory distress syndrome is caused by an excess of pulmonary surfactant.

Question 11

Boyle's law states that the pressure exerted by a gas varies directly with the volume of the gas.

Question 12

An increase in airway resistance and an increase in alveolar surface tension both increase the work of breathing.

Question 13

The pneumotaxic and apneustic centres are located in the cerebellum.

Question 14

The peripheral chemoreceptors are not activated during carbon monoxide poisoning despite the fact that the total O₂ content in the blood can become lethally low.

Question 15

If there is a deficient supply of pulmonary surfactant, the lungs become more compliant.

Question 16

Increased acidity at the tissue cells stimulates increased dissociation of oxyhaemoglobin.

Question 17

Slow, deep breathing is more effective for increasing alveolar ventilation than is rapid, shallow breathing.

Question 18

Pulmonary surfactant decreases surface tension to a greater degree in large alveoli than in small alveoli.

Question 19

The most important factor that determines the extent to which haemoglobin is saturated with oxygen is the blood P_O2.

Question 20

Arterial P_O2 remains normal or may even increase slightly during exercise, despite the fact that O₂ consumption by the tissues is greatly increased.

Question 21

At the end of inspiration and at the end of expiration, intra-alveolar pressure is always equal to atmospheric pressure.

Question 22

At a constant temperature, the pressure that a gas exerts depends on the volume that it occupies.

Question 23

Intrapleural pressure is usually less than atmospheric pressure.

Question 24

The combination of Hb and CO₂ is known as carbamino haemoglobin.

Question 25

Alveolar P_O2 is higher following inspiration than following expiration.

Question 26

The bronchioles are rigid, nonmuscular airways encircled by a series of cartilaginous rings.

Question 27

Inspiration is always an active process.

Question 28

The alveoli are encircled by capillaries.

Question 29

At the systemic capillaries, the P_O2 is in the range of the steep portion of the O_2-Hb curve.

Question 30

Intrapleural pressure normally does not equilibrate with the intra-alveolar pressure.

Question 31

To produce a normal tidal volume, the expiratory muscles must be stimulated.

Question 32

At the end of inspiration and at the end of expiration, intrapleural pressure is always equal to atmospheric pressure.

Question 33

Respiration is reflexively inhibited by alkalosis caused by a reduction in concentration of non-carbon dioxide-generated H⁺, the result of which is accumulation of H⁺-generating carbon dioxide to restore the acid-base balance toward normal.

Question 34

Pulmonary surfactant reduces the work of breathing and increases lung stability by increasing alveolar surface tension.

Question 35

Gases are transported during external respiration by active transport mechanisms.

Question 36

Respiration is accomplished entirely by the respiratory system.

Question 37

A slight decrease in arterial P_O2 below normal is a more potent stimulus toward increasing respiration than is a slight increase in P_CO2 above normal.

Question 38

Elastic recoil refers to the tendency of the chest wall to expand.

Question 39

A molecule of nitrogen gas exerts more pressure than a molecule of oxygen gas because nitrogen gas is a larger molecule.

Question 40

The skeletal muscles for breathing are located in the walls of the lungs.

Question 41

O₂ levels are much more closely regulated than CO₂ levels in the arterial blood.

Question 42

Air flow through the smaller bronchioles can be adjusted by varying the contractile activity of the smooth muscle within their walls.

Question 43

A highly compliant lung is easier to stretch than a less compliant one.

Question 44

Emphysema can be brought on by recurrent episodes of asthma and/or chronic bronchitis.

Question 45

Carbonic anhydrase catalyzes the formation of the oxyhaemoglobin.

Question 46

The respiratory system provides a route for water and heat elimination.

Question 47

Deep and slow breaths usually result in the greatest alveolar ventilation rates.

Question 48

Stimulation of the sympathetic nervous system and release of epinephrine lead to an increase in airway resistance.

Question 49

During external respiration, the P_CO2 is greater in the blood of the pulmonary capillaries than in the alveoli.

Question 50

The internal intercostal muscles are inspiratory muscles because they lift the ribs upward and outward to enlarge the thoracic cavity.

Question 51

The partial pressure of a gas in blood depends on the amount that is physically dissolved and not on the total content of the gas present in the blood.

Question 52

If a person is breathing rapidly, it is safe to assume that he or she is getting adequate ventilation.

Question 53

Expiration is always a passive process.

Question 54

In the plateau region of the O₂-Hb curve, a large decrease in P_O2 results in a small decrease in Hb saturation, whereas in the steep portion of the curve, a small decrease in P_O2 results in a large decrease in percent Hb saturation.

Question 55

The tidal volume is the sum of the vital capacity, expiratory reserve volume, and inspiratory reserve volume.

Question 56

If the tidal volume is 500 mL and the anatomic dead space volume is 150 mL, only 350 mL of air enters the alveoli during inspiration.

Question 57

The respiratory centre is located in the cerebral cortex.

Question 58

Patients suffering from chronic obstructive pulmonary disease generally have more trouble exhaling than inhaling.

Question 59

Both the respiratory system and the circulatory system are involved in the process of respiration.

Question 60

During external respiration, the P_O2 is greater in the alveoli than in the blood of the pulmonary capillaries.

Question 61

Pneumothorax develops from the accumulation of fluid in the alveoli.

Question 62

The most important factor controlling respiration is the P_O2 of arterial blood.

Question 63

The primary factor believed to be responsible for stimulating the profound and abrupt increase in ventilation during exercise is increased arterial P_CO2.

Question 64

Systemic arterial P_CO2 is less than tissue P_CO2.

Question 65

Intrapleural pressure is negative to maintain lung inflation.

Question 66

The respiratory system is the only system involved with the exchange of gas between the cells of an organism and the external environment.

Question 67

According to the law of LaPlace, the magnitude of the inward-directed collapsing pressure of a spherical bubble is directly proportional to both the surface tension and the radius of the bubble.

Question 68

When the inspiratory neurons stop firing, the expiratory muscles contract.

Question 69

Receptors in the CNS that detect changes in arterial P_CO2 are actually sensitive to the H⁺ concentration of the brain extracellular fluid.

Question 70

The residual volume is the amount of air remaining in the lungs at the end of a normal expiration.

Question 71

The respiratory airways filter, warm, and humidify incoming air.

Question 72

Pores of Kohn permit air flow between adjacent alveoli, a process known as collateral ventilation.

Question 73

The quantity of O₂ that will diffuse between the alveolar air and pulmonary blood depends solely on the partial pressure gradients that exist between the alveoli and the blood.

Question 74

All respiratory airways are held open by cartilaginous rings.

Question 75

The pleural cavity normally is not in direct communication with the lungs or atmosphere.

Question 76

Alveolar partial pressures do not fluctuate to any extent between inspiration and expiration.

Question 77

Pulmonary surfactant increases alveolar surface tension and does not affect lung expansion.

Question 78

The quantity of air that will flow into and out of the lungs depends solely on the radius of the respiratory airways.

Question 79

O₂ moves from the alveoli to the blood by active transport.

Question 80

In the breathing cycle, the atmospheric pressure normally does not change.