Deck 13: Respiratory Physiology

Question 1

Which is TRUE about the pleural sac?

A)It is continuous with the atmosphere and protects the lungs from infection.
B)It is a closed sac surrounding each lung that contains only a tiny volume of lubricating fluid.
C)It is a closed sac surrounding each lung and contains a large volume of surfactant.
D)It is a closed,air-filled space surrounding both lungs that has a negative pressure compared to atmospheric pressure.
E)It is bounded by pleural membranes that are very thin,which allows for abundant gas exchange.

Answer 1

B

Question 2

Which of these causes inhalation/inspiration?

A)Increase in the curvature (upward movement)of the diaphragm
B)Movement of the ribs closer together due to contraction of the internal intercostal muscles
C)Flattening (downward movement)of the diaphragm
D)Contraction of the abdominal muscles
E)Alveolar pressure increasing above atmospheric pressure

Answer 2

C

Question 3

During a physical examination,Joe learns that his resting tidal volume is 550 mL;his average resting respiratory rate is 15 breaths per minute;his total lung capacity is 6,000 mL;and his anatomic dead space is 150 mL.Joe's resting alveolar ventilation is

A)72.0 L/min.
B)6.0 L/min.
C)4.2 L/min.
D)1.8 L/min.
E)0.5 L/min.

Answer 3

B

Question 4

Under what condition is lung compliance increased?

A)Respiratory distress syndrome of the newborn
B)Prolonged shallow breathing
C)Cystic fibrosis
D)Emphysema
E)Asthma

Question 5

Which of the following drugs,administered as an aerosol spray,would be most likely to help a patient during an asthmatic attack?

A)Pulmonary surfactant
B)A β₂-adrenergic agonist
C)A muscarinic agonist
D)Histamine
E)A β₂-adrenergic antagonist

Question 6

Which of the following is most responsible for keeping the lung surface and the thoracic wall from separating?

A)The presence of surfactant
B)The negative pressure in the alveolar space
C)The force exerted by the external intercostal muscles
D)Subatmospheric intrapleural pressure
E)Alveolar pressure is higher than atmospheric pressure

Question 7

Which of the following statements about the response of arteriolar smooth muscle to changing oxygen partial pressures is TRUE?

A)Both systemic and pulmonary arterioles respond to a decrease in PO₂ by constricting.
B)Both systemic and pulmonary arterioles respond to a decrease in PO₂ by dilating.
C)Systemic arterioles respond to a decrease in PO₂ by dilating,but pulmonary arterioles constrict in response to decreased PO₂.
D)Systemic arterioles respond to a decrease in PO₂ by constricting,but pulmonary arterioles dilate in response to decreased PO₂.
E)Changes in PO₂ do not affect arteriolar smooth muscle in the pulmonary system.

Question 8

Under normal circumstances,which of the following would result from an increase in transpulmonary pressure?

A)Inhalation/inspiration
B)Exhalation/expiration
C)A collapsed lung
D)Pneumothorax
E)Emphysema

Question 9

Which is normally TRUE about the intrapleural pressure?

A)It is lower than alveolar pressure.
B)It is between +5 and +10 mmHg above atmospheric pressure at functional residual capacity.
C)It alternates between being less than,and greater than,atmospheric pressure.
D)During a passive exhale,it increases to a value above atmospheric pressure.
E)It is always the same as atmospheric pressure during a passive exhale.

Question 10

Which of the following is NOT a function of the respiratory system?

A)Net uptake of carbon dioxide from the air and removal of oxygen from the blood
B)Regulation of blood H⁺ concentration
C)Trapping of blood clots
D)Phonation
E)Defense against microbes

Question 11

What is one function of the type II alveolar cells?

A)Production of surfactant
B)Secretion of mucus
C)Phagocytizing bacteria and other foreign particles
D)Make up the majority of the epithelial wall of the alveoli
E)Lining the pleural space

Question 12

Which of the following is TRUE during the initial stage of an asthma attack?

A)ΔP is increased.
B)ΔP is decreased.
C)R is increased.
D)R is decreased.
E)None of these,flow rate is unchanged during an asthma attack.

Question 13

During a yoga class you take a deep breath,then relax and let the breath out slowly.During that exhalation,which would NOT be true?

A)Alveolar pressure is greater than atmospheric pressure.
B)Intrapleural pressure is greater than alveolar pressure.
C)Intrapleural pressure becomes less negative.
D)The diaphragm relaxes.
E)Lung volume decreases.

Question 14

When lying down,a subject's respiratory rate is 12 breaths per minute,his anatomical dead space is 150 mL,and his minute ventilation is 7 L/min.Which of these is closest to his alveolar ventilation in liters per minute?

A)6.0
B)5.2
C)4.2
D)3.0
E)0.583

Question 15

Which structure is NOT part of the "anatomical dead space"?

A)Bronchiole
B)Trachea
C)Bronchus
D)Respiratory bronchiole
E)Terminal bronchiole

Question 16

Which of the following is a cause of asthma?

A)Loss of alveoli
B)Inflammation of the bronchioles
C)Elevation of intrapleural pressure to equal atmospheric pressure
D)Environmental chemicals that stimulate β₂-adrenergic receptors
E)Lack of pulmonary surfactant

Question 17

Type II alveolar cells are among the last cells to mature during fetal development.In babies born prematurely,type II alveolar cells are often not ready to perform their function.Which of the following would be TRUE of these babies?

A)They would be at risk of alveolar collapse due to too much surface tension in the alveoli.
B)They would be at risk of bacterial infections in the lungs.
C)They would be at risk of autoimmune diseases with lung complications.
D)They would be more likely to have coughing fits.
E)None of these would occur.

Question 18

Type II alveolar cells are among the last cells to mature during fetal development.In babies born prematurely,type II alveolar cells are often not ready to perform their functions.Which of the following drugs would be most likely to help an infant with immature type II alveolar cells?

A)Pulmonary surfactant
B)A beta-adrenergic agonist
C)A muscarinic agonist
D)Histamine
E)A beta-adrenergic antagonist

Question 19

The volume of air flowing into the alveoli during inhalation/inspiration is increased when there is an increase in which of these?

A)Airway resistance
B)The pressure gradient from the atmosphere to the alveoli
C)The pressure in the intrapleural space
D)The curvature of the diaphragm
E)The volume of air in the intrapleural space

Question 20

Which of the following statements regarding pulmonary surfactant is TRUE?

A)It is secreted by type I alveolar cells.
B)It increases the compliance of the lungs.
C)It increases airway resistance.
D)It is secreted into the intrapleural space.
E)It can only interact with other lipid molecules.

Question 21

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-Bötzinger complex
C)The dorsal respiratory group of the medulla oblongata
D)The pneumotaxic center of the pons
E)The apneustic center of the pons

Question 22

You walk into your dorm room and find your roommate in the midst of anxiety-induced hyperventilation.You're unable to calm her down,so you call an ambulance.When she arrives at the ER,which of the following is her likely diagnosis?

A)Respiratory alkalosis
B)Respiratory acidosis
C)Increased blood PCO₂
D)Metabolic acidosis
E)Metabolic alkalosis

Question 23

You're resting on the couch watching TV.Which of the following is the most likely reflection of the values in your body? Regarding the partial pressures of O₂ and CO₂,which of the following statements is true in a normal person at rest?

A)Atmospheric PO₂ is approximately 100 mmHg and the alveolar PO₂ is approximately 160 mmHg.
B)The PCO₂ in the air is approximately 40 mmHg and the alveolar PCO₂ is approximately 60 mmHg.
C)The PO₂ in the systemic arteries is approximately 100 mmHg and the alveolar PO₂ is approximately 105 mmHg.
D)PCO₂ in the systemic veins is less than systemic arterial PCO₂.
E)PCO₂ in the pulmonary arteries is less than pulmonary venous PCO₂.

Question 24

During a run,your gastrocnemius (calf)muscle has a temperature of 38.5° C,while your biceps brachii (upper arm)muscle has a temperature of 37.5° C.Which of the following is TRUE of the red blood cells as they pass by these muscles?

A)The hemoglobin molecules will have the same affinity for oxygen at both locations.
B)The hemoglobin molecules will have a higher affinity for oxygen as they pass by the biceps brachii compared to the gastrocnemius.
C)The hemoglobin molecules will have a higher affinity for oxygen as they pass by the gastrocnemius compared to the biceps brachii.
D)The hemoglobin molecules may denature as they pass by the gastrocnemius.

Question 25

Which of these is demonstrated by the oxygen-hemoglobin dissociation curve?

A)The greater the PO₂ of the blood,the greater the dissociation of O₂ from hemoglobin.
B)At normal resting systemic arterial PO₂,hemoglobin is almost 100% saturated with oxygen.
C)At normal resting systemic venous PO₂,only about 75% of the hemoglobin is in the form of deoxyhemoglobin.
D)More additional oxygen binds to hemoglobin when going from a PO₂ of 60 to 100 mmHg,than is added when going from a PO₂ of 40 to 60 mmHg.
E)As PO₂ increases,the saturation of hemoglobin with oxygen increases linearly.

Question 26

You embark on a hiking trip on Mt.Kilimanjaro (altitude = 19,000 ft;Atmospheric air pressure = 379 mmHg).As you ascend,what happens to the PO₂ in the alveoli?

A)No change from sea level,as long as we breathe in the same volume of air.
B)Alveolar PO₂ decreases.
C)Alveolar PO₂ increases.

Question 27

Regarding the relationships between the rates of oxygen consumption/carbon dioxide production and alveolar ventilation,which of these statements is TRUE?

A)Increased ventilation without a similar increase in metabolism is called hypoventilation.
B)In hypoventilation,alveolar PCO₂ decreases below resting levels.
C)In hyperventilation,alveolar PCO₂ can decrease to zero.
D)A decrease in metabolism without a similar decrease in alveolar ventilation would result in hyperventilation.
E)An increase in ventilation with a matching increase in metabolism is called hyperventilation.

Question 28

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

Question 29

When you head to bed at night,you bring a glass of tap water with you and set it on the nightstand.Upon waking in the morning,you discover there are tiny gas bubbles along the sides of the container.The best explanation for this is

A)the concentration of a particular gas in a liquid equilibrates to match the concentration of that gas in the air to which the liquid is exposed.
B)different gasses have the same solubility in liquids.
C)the partial pressure of a gas in a liquid is equal to the amount freely diffusing in the liquid plus the amount bound to large molecules within the liquid.
D)the partial pressure of a particular gas in a liquid equilibrates to match the partial pressure of that gas in the air to which the liquid is exposed.
E)as the partial pressure of a particular gas in an air sample increases,the concentration of that gas in a liquid exposed to that air sample decreases.

Question 30

Which of the following would cause a decrease in the binding affinity of hemoglobin for oxygen?

A)Increased pH of the blood
B)Increased temperature of the blood
C)Decreased DPG levels in erythrocytes
D)The presence of carbon monoxide
E)Decreased concentration of H⁺ in the blood

Question 31

A decrease in metabolism without a similar,compensatory decrease in alveolar ventilation will have what effect on the systemic pH?

A)pH will decrease.
B)pH will increase.
C)No change to pH is expected in this circumstance.
D)It is impossible to predict the effect on pH without first understanding why metabolism decreased.

Question 32

You embark on a hiking trip on Mt.Kilimanjaro (altitude = 19,000 ft;Atmospheric air pressure = 379 mmHg).mHg).As you ascend,what are you likely to notice about your breathing?

A)You need to work to exhale,using your muscles to decrease your thoracic size beyond what is normal
B)You need to work harder to inhale,expanding your thoracic size beyond what is normal
C)Both would happen
D)Neither would happen

Question 33

In which form is most of the oxygen carried in arterial blood?

A)Bound to hemoglobin
B)Dissolved in the plasma
C)Dissolved in the cytosol of erythrocytes
D)Converted to HCO₃⁻
E)Bound to myoglobin

Question 34

You (a healthy individual)are swimming underwater when you can no longer resist the urge to breathe.This overwhelming urge is probably due to

A)the autorhymthic cells in your diaphragm contracting.
B)the decrease in O₂ available to the cells of the body.
C)the increase in plasma H⁺.
D)the increase in pH has made your blood dangerously alkaline.

Question 35

Maria is a patient in the ward who was recently in a motor vehicle accident.Her injuries are causing her a lot of pain,and as a consequence to the morphine she's been given,her respiratory rate is quite low.Which of the following is likely to be TRUE?

A)The pH of her blood has increased.
B)The level of O₂ in her blood has increased.
C)The level of H⁺ ions in her blood has increased.
D)The alveolar CO₂ has decreased to near atmospheric levels.
E)The alveolar O₂ level has increased toward atmospheric levels.

Question 36

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.

Question 37

If all other factors remain the same,which of these results in an increase in the amount of oxygen bound to hemoglobin?

A)Increased plasma [H⁺]
B)Increased plasma temperature
C)Increased plasma [2,3 diphosphoglycerate]
D)Increased plasma PO₂
E)Increased plasma [carbon monoxide]

Question 38

After CO₂ is produced by tissues,in what form is most of that carbon transported to the lungs for removal from the body?

A)As dissolved CO₂
B)Bound to hemoglobin
C)As H₂CO₃
D)As dissolved HCO₃⁻
E)As carbonic anhydrase

Question 39

Carbonic anhydrase catalyzes a reaction that combines which of the following?

A)H₂O and O₂
B)H₂O and CO₂
C)H₂O and CO
D)H⁺ and HCO₃⁻
E)CO₂ and O₂
Answₑᵣ: B

Question 40

Which of the following is NOT true regarding ventilation-perfusion inequality?

A)No inequality exists in normal lungs.
B)It may result from increased alveolar dead space.
C)It is increased from normal in patients with emphysema.
D)It is caused by too little or too much blood flow relative to ventilation.
E)It is caused by too little or too much ventilation relative to blood flow.

Question 41

Drug X is a new drug to treat Alzheimer's Disease.This drug is able to cross the blood-brain barrier and circulate in the CSF.The drug is slightly acidic and at the recommended dose it decreases the CSF pH from 7.4 to 7.3.Will Drug X have any effect on respiration?

A)It will cause an increase in respiratory rate.
B)It will cause a decrease in respiratory rate.
C)It will have no effect on respiratory rate,but will cause an increase in depth of breathing.
D)It will have no effect on respiratory rate,but will cause the patient to take shallower breaths.
E)It will not impact respiratory function.

Question 42

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

Question 43

Which of the following statements regarding hypoxia is correct?

A)Exposure to high altitude is a form of hypoxic hypoxia.
B)"Anemic hypoxia" refers to the condition of lower than normal arterial PO₂.
C)Carbon monoxide poisoning is an example of hypoxic hypoxia.
D)Carbon monoxide poisoning is an example of ischemic hypoxia.
E)Cyanide poisoning is an example of hypoxic hypoxia.

Question 44

What is the primary regulator of the magnitude of alveolar ventilation under normal circumstances?

A)The H⁺ concentration in the brain extracellular fluid,which is monitored by central chemoreceptors
B)The PO₂ of the arterial blood,which is monitored by central chemoreceptors
C)The PO₂ of the arterial blood,which is monitored by peripheral chemoreceptors
D)The H⁺ concentration in the arterial blood,which is monitored by central chemoreceptors
E)Stretch receptors in the lung

Question 45

The process of ventilation includes both the transport of gases by bulk flow and the diffusion of gases into and out of the blood.

Question 46

The diaphragm is a large sheet of smooth muscle that separates the thoracic cavity from the abdomen.

Question 47

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

Question 48

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.

Question 49

Susan had heart surgery in October and during the surgery,by accident,the surgeon damaged one of her phrenic nerves leading to paralysis of half of her diaphragm.The following day,lab values will indicate that her arterial PO₂ is decreased.

Question 50

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.

Question 51

During inhalation/inspiration,the diaphragm contracts and the alveolar pressure is less than atmospheric pressure;during exhalation/expiration,the diaphragm relaxes and the alveolar pressure is greater than atmospheric pressure.

Question 52

Susan had heart surgery in October and during the surgery,by accident,the surgeon damaged one of her phrenic nerves leading to paralysis of half of her diaphragm.Immediately upon waking up from surgery,Susan will find that her respiratory rate has decreased.

Question 53

Which correctly describes the cause of the increase in alveolar ventilation that occurs when a person ascends to high altitude?

A)The decrease in PCO₂ of inspired air decreases alveolar PCO₂,stimulating the peripheral chemoreceptors.
B)The decrease in PCO₂ of inspired air decreases alveolar PCO₂,stimulating the central chemoreceptors.
C)The decrease in PO₂ of inspired air decreases alveolar and arterial PO₂,stimulating the peripheral chemoreceptors.
D)The decrease in total atmospheric pressure causes a greater negative pressure in the intrapleural space,resulting in deeper and more frequent breathing. 
E)The decrease in the total barometric pressure at high altitude causes hypocapnea,which stimulates peripheral chemoreceptors.

Question 54

Which is characteristic of a person chronically suffering from hypoxic hypoxia?

A)Higher-than-normal alveolar PO₂ 
B)Higher-than-normal hematocrit
C)Higher-than-normal arterial PO₂
D)Lower-than-normal lactic acid production 
E)Lower-than-normal blood flow through tissues

Question 55

If the parietal pleura is cut during surgery,the lung on the side of the cut will expand and the chest wall will be compressed.

Question 56

During inhalation/inspiration,the total alveolar volume decreases.

Question 57

Which of the following conditions would result in a systemic arterial PO₂ lower than is typical of a healthy person at sea level?

A)Traveling to high altitude
B)Breathing 100% oxygen
C)Having iron-deficiency anemia
D)Breathing regular air in a hyperbaric chamber (higher that normal atmospheric pressure)
E)Maintaining alveolar ventilation constant while decreasing metabolic rate

Question 58

Following strenuous exercise,blood levels of lactic acid are ________ compared to pre-exercise levels.This change in acid concentration causes a reflex ________ in ventilation by activating ________.

A)decreased;decrease;peripheral chemoreceptors
B)decreased;decrease;central chemoreceptors
C)increased;increase;baroreceptors in the aortic arch
D)increased;increase;central chemoreceptors
E)increased;increase;peripheral chemoreceptors

Question 59

You've just stepped on the treadmill and are beginning to increase your speed.As you reach your maximum,which of the following values will NOT increase?

A)Minute ventilation
B)Arterial PCO₂
C)Oxygen delivery to muscles
D)Oxygen extraction from the blood by muscles
E)Body heat production

Question 60

According to Boyle's law,the pressure exerted by a constant number of gas molecules in a container is inversely proportional to the volume of the container.Therefore,increasing the volume of the container will cause a decrease in its pressure.

Question 61

A disease that causes obstruction in the bronchioles is likely to result in lowered systemic arterial pH.

Question 62

At sea level,atmospheric PO₂ is about 760 mmHg.

Question 63

In a normal person at rest,the part of the respiratory cycle in which no air is flowing through the airways and the respiratory muscles are relaxed is at the end of inhalation/inspiration,prior to exhalation/expiration.

Question 64

In the systemic circulation,the PO₂ of arterial blood exceeds the PO₂ of venous blood,while the reverse is true for the pulmonary circulation.

Question 65

Mixed venous blood in a resting individual still contains more than double the amount of oxygen extracted by the tissues as the blood passed through them.

Question 66

When blood flows into the systemic capillaries,the PO₂ of the erythrocytes is greater than the PO₂ of the interstitial fluid,causing a shift from oxyhemoglobin to deoxyhemoglobin.

Question 67

A clinical sign of obstructive lung disease would be a reduced FEV1/FVC ratio,where "FVC" is "forced" VC.

Question 68

The affinity of hemoglobin for O₂ is decreased in rapidly metabolizing tissues.

Question 69

An individual in Boston (sea level)will have a lower tidal volume than an individual in Denver (5,280 feet above sea level).

Question 70

Emphysema is a disease characterized by low lung compliance,obstructed airways,and ventilation-perfusion inequality.

Question 71

The diameter of the airways in normal lungs is generally great enough that little resistance is offered to airflow.

Question 72

An individual with emphysema will have a lower tidal volume than an individual of the same size without emphysema.

Question 73

Doubling the frequency of breathing will cause a greater increase in alveolar ventilation than will doubling the depth of inspiration.

Question 74

Most of the O₂ carried in the blood is dissolved in plasma.

Question 75

Infants born prematurely frequently develop respiratory distress syndrome of the newborn because they have too few alveoli to exchange O₂ and CO₂ efficiently.

Question 76

Normal,resting exhalation/expiration of air from the lungs requires contraction of the exhalatory/expiratory intercostal muscles.

Question 77

If lung disease results in an arterial PO₂ of 80 mmHg,the total amount of oxygen carried by the blood is 20% below normal.

Question 78

Decreased alveolar PO₂ causes reflex vasodilation of the pulmonary arterioles.

Question 79

In an individual experiencing an asthma attack,arterial blood levels of PO₂ will decrease and arterial blood levels of PCO₂ will increase.

Question 80

The total dead space in the lungs includes anatomic dead space and any portion of the alveoli that has little or no blood supply.