The cricoid cartilage is unique because it is:

The largest laryngeal cartilage

The cricothyroid membrane is located:

Between the first tracheal rings

Chest pressure drops and air flows in

Chest pressure rises above atmospheric

The diaphragm relaxes and rises

Normal exhalation at rest is:

Controlled by the abdominal muscles

Minute volume is calculated as:

Tidal volume x respiratory rate

The term respiration refers to:

Gas exchange in lungs and tissues

The number of breaths per minute

Moving air in and out of the lungs

A hypothermic, alkalotic patient has an SpO2 of 97% but signs of tissue hypoxia. The best explanation is:

A left curve shift makes hemoglobin hold oxygen tightly

A right curve shift releases oxygen too early

Alkalosis lowers the total hemoglobin available to carry oxygen

Cold speeds the unloading of oxygen to tissue

A pulmonary embolism creates which ventilation/perfusion problem?

Global hypoventilation of the lungs

A diffusion barrier at the alveolar wall

The upper airway extends from the:

Pharynx to the mainstem bronchi

The turbinates function to:

Dry inspired air before the lungs

Seal the nasopharynx when swallowing

Opens into larynx and esophagus

Lies directly behind the nasal cavity

The hyoid bone is unique because it:

Is fused to the base of the skull

Is the smallest bone in the body

The trachea is held open by:

Complete cartilage rings throughout

Cilia in the airway function to:

Exchange gases with capillary blood

The bronchioles differ from bronchi because they:

Have a larger diameter than bronchi

A patient with a complete C7 spinal cord injury breathes with his abdomen rising but little chest wall movement. Why?

The phrenic nerve (C3-C5) still works; the intercostals do not

The diaphragm is paralyzed, so the chest wall does the work

The phrenic nerve arises at T1, below the injury level

Abdominal muscles contract to drive each breath, replacing the diaphragm

Respiratory System Practice Questions

105 multiple-choice questions on Respiratory system for paramedic and EMT students, from Chapter 8 (Anatomy and Physiology). Read each question, pick your answer, then tap Show answer to check it and read the explanation.

Drill this section: 5 in a row Take the Chapter 8 test

105 practice questions

What are the three regions of the pharynx?
1. A. Naso-, oro-, laryngopharynx
2. B. Glottis, epiglottis, vallecula
3. C. Larynx, trachea, bronchi
4. D. Nasal cavity, sinuses, mouth
Show answer
Answer: A. Naso-, oro-, laryngopharynx
The regions are the nasopharynx, oropharynx, and laryngopharynx. The laryngopharynx (hypopharynx) sits just above the larynx and esophagus.
The structure that covers the glottis during swallowing is the:
1. A. Uvula
2. B. Vallecula
3. C. Epiglottis
4. D. Cricoid cartilage
Show answer
Answer: C. Epiglottis
The epiglottis prevents aspiration of food and liquid.
The vallecula is:
1. A. Recess at the back of the nasal cavity
2. B. The lowest part of the trachea
3. C. Space between tongue and epiglottis
4. D. The opening between the vocal cords
Show answer
Answer: C. Space between tongue and epiglottis
The curved (Macintosh) laryngoscope blade tip is placed in the vallecula.
The cricoid cartilage is unique because it is:
1. A. The Adam's apple
2. B. Attached to the epiglottis
3. C. The largest laryngeal cartilage
4. D. Only complete cartilage ring
Show answer
Answer: D. Only complete cartilage ring
The thyroid cartilage is the Adam's apple. The cricoid is the complete ring just below it.
The cricothyroid membrane is located:
1. A. Between hyoid and thyroid
2. B. At the level of the carina
3. C. Between the first tracheal rings
4. D. Between thyroid and cricoid
Show answer
Answer: D. Between thyroid and cricoid
This is the site for a surgical or needle cricothyrotomy.
The narrowest part of the adult airway is the:
1. A. Vocal cords
2. B. Cricoid ring
3. C. Midtrachea
4. D. Nasopharynx
Show answer
Answer: A. Vocal cords
In adults, the glottic opening is the narrowest point.
The trachea divides into the right and left mainstem bronchi at the:
1. A. Hilum
2. B. Glottis
3. C. Alveolar sac
4. D. Carina
Show answer
Answer: D. Carina
The carina is at about the level of the angle of Louis (T4-T5).
Aspirated objects and deep ET tubes most often enter the right mainstem bronchus because it is:
1. A. Shorter, wider, straighter
2. B. More muscular and rigid
3. C. Longer and more horizontal
4. D. Displaced by the heart
Show answer
Answer: A. Shorter, wider, straighter
Always check for equal breath sounds after intubation.
Gas exchange between the lungs and blood occurs in the:
1. A. Bronchioles
2. B. Alveoli
3. C. Trachea
4. D. Bronchi
Show answer
Answer: B. Alveoli
The bronchi and bronchioles only conduct air.
Surfactant functions to:
1. A. Produce airway mucus
2. B. Lower alveolar surface tension
3. C. Trap inhaled dust and bacteria
4. D. Stimulate the cough reflex
Show answer
Answer: B. Lower alveolar surface tension
Without surfactant the alveoli collapse (atelectasis). Premature infants often lack it.
The pleura consist of the:
1. A. Bronchi and bronchioles
2. B. Epiglottis and glottis
3. C. Alveoli and capillaries
4. D. Visceral and parietal
Show answer
Answer: D. Visceral and parietal
The visceral pleura covers the lungs; the parietal pleura lines the chest wall. The potential space between them is where air (pneumothorax) or blood (hemothorax) collects.
The primary muscle of breathing is the:
1. A. Intercostals
2. B. Diaphragm
3. C. Abdominal muscles
4. D. Sternocleidomastoid
Show answer
Answer: B. Diaphragm
Using accessory muscles, such as the neck and abdominal muscles, is a sign of distress.
During inhalation:
1. A. Chest pressure rises above atmospheric
2. B. Air is pushed out by recoil
3. C. Chest pressure drops and air flows in
4. D. The diaphragm relaxes and rises
Show answer
Answer: C. Chest pressure drops and air flows in
The diaphragm contracts, dropping chest pressure. Breathing is driven by negative pressure. Positive-pressure ventilation, like bagging, reverses this.
Normal exhalation at rest is:
1. A. Active
2. B. Controlled by the abdominal muscles
3. C. Passive
4. D. Triggered by high oxygen
Show answer
Answer: C. Passive
The muscles relax and elastic recoil pushes air out. Forced exhalation, as in asthma, is active.
Normal adult tidal volume is approximately:
1. A. 150 mL
2. B. 500 mL
3. C. 250 mL
4. D. 1,000 mL
Show answer
Answer: B. 500 mL
About 500 mL, or 5-7 mL/kg.
Anatomic dead space, air that does not reach the alveoli, is about:
1. A. 500 mL
2. B. 50 mL
3. C. 1,200 mL
4. D. 150 mL
Show answer
Answer: D. 150 mL
Shallow breathing mostly moves dead space air, so fast, shallow breaths ventilate poorly.
Minute volume is calculated as:
1. A. Tidal volume x respiratory rate
2. B. Tidal volume - dead space
3. C. Respiratory rate x heart rate
4. D. Vital capacity / rate
Show answer
Answer: A. Tidal volume x respiratory rate
For example, 500 mL x 12 is 6 L/min.
Residual volume is the air:
1. A. Inhaled with maximal effort
2. B. Moved in a normal breath
3. C. Left after a full exhalation
4. D. Held in the conducting airways
Show answer
Answer: C. Left after a full exhalation
Residual volume keeps the alveoli from collapsing.
The term respiration refers to:
1. A. The number of breaths per minute
2. B. Loading oxygen onto hemoglobin
3. C. Moving air in and out of the lungs
4. D. Gas exchange in lungs and tissues
Show answer
Answer: D. Gas exchange in lungs and tissues
Ventilation is moving air. Respiration is gas exchange. Oxygenation is loading oxygen into the blood.
Room air contains approximately what percentage of oxygen?
1. A. 50%
2. B. 78%
3. C. 21%
4. D. 16%
Show answer
Answer: C. 21%
Room air is 21% oxygen. Nitrogen makes up about 78%.
A patient hyperventilates and his CO2 falls. Using CO2 + H2O = H2CO3 = H+ + HCO3-, what happens to hydrogen ions and pH?
1. A. H+ rises, so pH falls
2. B. H+ is unchanged
3. C. H+ falls, so pH falls
4. D. H+ falls, so pH rises
Show answer
Answer: D. H+ falls, so pH rises
Removing CO2 pulls the reaction to the left, using up H+, so H+ falls and pH rises (respiratory alkalosis). Rising H+ with falling pH is what happens in hypoventilation. pH moves opposite to H+, so a fall in H+ cannot lower pH.
A hypothermic, alkalotic patient has an SpO2 of 97% but signs of tissue hypoxia. The best explanation is:
1. A. A right curve shift releases oxygen too early
2. B. Alkalosis lowers the total hemoglobin available to carry oxygen
3. C. Cold speeds the unloading of oxygen to tissue
4. D. A left curve shift makes hemoglobin hold oxygen tightly
Show answer
Answer: D. A left curve shift makes hemoglobin hold oxygen tightly
Cold, alkalosis, and low CO2 shift the oxyhemoglobin curve to the left. Hemoglobin is well saturated but gives up less oxygen to the tissues. A right shift, caused by fever, acidosis, and high CO2, makes release easier. Cold slows oxygen unloading rather than speeding it, and alkalosis changes hemoglobin's affinity, not the amount of hemoglobin.
A pulmonary embolism creates which ventilation/perfusion problem?
1. A. Ventilated but not perfused
2. B. Global hypoventilation of the lungs
3. C. Perfused but not ventilated
4. D. A diffusion barrier at the alveolar wall
Show answer
Answer: A. Ventilated but not perfused
The alveoli get air but no blood flow (dead space). Pneumonia is the opposite: blood flow without air (a shunt). Ventilation is preserved in a PE, so it is not hypoventilation, and the alveolar membrane is normal, so there is no diffusion barrier.
The respiratory centers are located in the:
1. A. Cerebellum
2. B. Medulla and pons
3. C. Cerebrum
4. D. Hypothalamus
Show answer
Answer: B. Medulla and pons
The medulla sets the breathing rhythm and the pons fine-tunes it.
In a healthy person, what is the primary stimulus to breathe?
1. A. Falling oxygen levels
2. B. Rising carbon dioxide levels
3. C. Rising blood pressure
4. D. Lung stretch receptors
Show answer
Answer: B. Rising carbon dioxide levels
Central chemoreceptors detect rising CO2 through a drop in CSF pH.
Peripheral chemoreceptors that mainly sense low oxygen are located in the:
1. A. Medulla oblongata
2. B. Alveolar walls
3. C. Carotid bodies
4. D. Pontine center
Show answer
Answer: C. Carotid bodies
They are in the carotid bodies and the aortic arch. This hypoxic drive is the backup and matters in some patients who chronically retain CO2.
Which reflex prevents overinflation of the lungs?
1. A. Cushing reflex
2. B. Cough reflex
3. C. Hering-Breuer reflex
4. D. Bainbridge atrial reflex
Show answer
Answer: C. Hering-Breuer reflex
Stretch receptors in the lungs stop further inhalation. The cough reflex clears irritants from the airway, and the Bainbridge reflex raises heart rate when the atria are stretched; neither limits lung inflation.
The upper airway extends from the:
1. A. Bronchioles to alveoli
2. B. Nose and mouth to the larynx
3. C. Pharynx to the mainstem bronchi
4. D. Carina to the alveoli
Show answer
Answer: B. Nose and mouth to the larynx
The lower airway begins below the larynx.
The nasal passages warm, filter, and:
1. A. Begin gas exchange
2. B. Humidify air
3. C. Equalize middle ear pressure
4. D. Cool inspired air
Show answer
Answer: B. Humidify air
Bypassing the nose with an advanced airway removes that function. No gas exchange occurs in the nose; it begins in the respiratory bronchioles and alveoli. The eustachian tube equalizes middle ear pressure. The nose warms rather than cools air.
The turbinates function to:
1. A. Create turbulent airflow
2. B. Support the hard palate
3. C. Dry inspired air before the lungs
4. D. Seal the nasopharynx when swallowing
Show answer
Answer: A. Create turbulent airflow
The turbulence warms and filters the air. They also make nasal airway insertion prone to bleeding. By slowing and mixing airflow over moist mucosa, they humidify rather than dry the air.
The oropharynx is located:
1. A. Behind the nasal cavity
2. B. Within the mediastinum
3. C. Behind the mouth
4. D. Below the vocal cords
Show answer
Answer: C. Behind the mouth
It runs from the soft palate to the epiglottis. The nasopharynx lies above it.
The laryngopharynx:
1. A. Opens into larynx and esophagus
2. B. Is part of the trachea
3. C. Contains the vocal cords
4. D. Lies directly behind the nasal cavity
Show answer
Answer: A. Opens into larynx and esophagus
It is the lowest pharyngeal region. It is also called the hypopharynx.
The larynx contains the:
1. A. Vallecula
2. B. Carina
3. C. Vocal cords
4. D. Tongue base
Show answer
Answer: C. Vocal cords
The space between the cords is the glottic opening. It connects the pharynx to the trachea. The vallecula lies above the larynx, between the tongue base and epiglottis, and the tongue base forms the front wall of the oropharynx. The carina is far below, where the trachea divides.
The thyroid cartilage is commonly known as the:
1. A. Epiglottis
2. B. Adam's apple
3. C. Cricoid ring
4. D. Hyoid bone
Show answer
Answer: B. Adam's apple
It is the largest laryngeal cartilage.
The hyoid bone is unique because it:
1. A. Is fused to the base of the skull
2. B. Is made entirely of cartilage
3. C. Articulates with no other bone
4. D. Is the smallest bone in the body
Show answer
Answer: C. Articulates with no other bone
The tongue and larynx attach to it.
The trachea is held open by:
1. A. C-shaped cartilage rings
2. B. Elastic fibers alone
3. C. Smooth muscle alone
4. D. Complete cartilage rings throughout
Show answer
Answer: A. C-shaped cartilage rings
The open side faces the esophagus.
The trachea in an adult is approximately:
1. A. 10 to 12 cm long
2. B. 2 to 4 cm long
3. C. 20 cm long
4. D. 30 cm long
Show answer
Answer: A. 10 to 12 cm long
It divides at the carina.
Cilia in the airway function to:
1. A. Produce protective mucus
2. B. Warm inspired air
3. C. Exchange gases with capillary blood
4. D. Sweep mucus toward the pharynx
Show answer
Answer: D. Sweep mucus toward the pharynx
Smoking damages them.
Goblet cells produce:
1. A. Surfactant
2. B. Enzymes
3. C. Mucus
4. D. Cilia
Show answer
Answer: C. Mucus
Excess mucus contributes to airway obstruction.
The bronchioles differ from bronchi because they:
1. A. Perform most gas exchange
2. B. Have a larger diameter than bronchi
3. C. Have complete cartilage rings
4. D. Lack cartilage support
Show answer
Answer: D. Lack cartilage support
Relying on smooth muscle makes them prone to bronchospasm. This is why beta-2 agonists work there.
Each alveolus is surrounded by:
1. A. Pulmonary capillaries
2. B. Smooth muscle
3. C. Cartilage plates
4. D. Connective tissue only
Show answer
Answer: A. Pulmonary capillaries
The alveolar-capillary membrane is extremely thin.
Type II alveolar cells produce:
1. A. Surfactant
2. B. Cilia
3. C. Histamine
4. D. Mucus
Show answer
Answer: A. Surfactant
Surfactant lowers surface tension.
Atelectasis refers to:
1. A. Collapse of alveoli
2. B. Air in the pleural space
3. C. Airway narrowing
4. D. Fluid in the alveoli
Show answer
Answer: A. Collapse of alveoli
It reduces the surface area for gas exchange.
The right lung has how many lobes?
1. A. One
2. B. Three
3. C. Two
4. D. Four
Show answer
Answer: B. Three
The left has two, making room for the heart.
The cardiac notch is found in the:
1. A. Diaphragm
2. B. Left lung
3. C. Right lung
4. D. Trachea
Show answer
Answer: B. Left lung
It accommodates the heart.
The visceral pleura covers the:
1. A. Diaphragm only
2. B. Lung surface
3. C. Chest wall
4. D. Mediastinum only
Show answer
Answer: B. Lung surface
The parietal pleura lines the thoracic cavity.
The pleural space normally contains:
1. A. A thin layer of air
2. B. A thin film of fluid
3. C. Nothing at all
4. D. A small amount of blood
Show answer
Answer: B. A thin film of fluid
The fluid lubricates the pleural surfaces. It is a potential space.
Negative intrapleural pressure is important because it:
1. A. Forces air out on exhalation
2. B. Keeps the lungs expanded
3. C. Collapses the lungs at rest
4. D. Prevents gas diffusion
Show answer
Answer: B. Keeps the lungs expanded
It holds the lungs against the chest wall. Loss of it produces pneumothorax.
A tension pneumothorax impairs circulation by:
1. A. Increasing cardiac preload
2. B. Reducing venous return
3. C. Lowering oxygen levels only
4. D. Causing severe bronchospasm
Show answer
Answer: B. Reducing venous return
Rising intrathoracic pressure compresses the lung and impedes venous return. Hypotension and distended neck veins may appear.
A patient with a complete C7 spinal cord injury breathes with his abdomen rising but little chest wall movement. Why?
1. A. The diaphragm is paralyzed, so the chest wall does the work
2. B. The phrenic nerve arises at T1, below the injury level
3. C. The phrenic nerve (C3-C5) still works; the intercostals do not
4. D. Abdominal muscles contract to drive each breath, replacing the diaphragm
Show answer
Answer: C. The phrenic nerve (C3-C5) still works; the intercostals do not
The diaphragm is supplied by the phrenic nerve from C3 to C5, which is above this injury, so it still works. The intercostals (thoracic nerves) are paralyzed, causing diaphragmatic, 'belly' breathing with reduced reserve. Injuries above C3 can paralyze the diaphragm. The abdominal muscles are also paralyzed below this level; the abdomen rises passively as the diaphragm descends.
During inhalation, the diaphragm:
1. A. Contracts and rises
2. B. Relaxes and rises
3. C. Contracts and descends
4. D. Relaxes and descends
Show answer
Answer: C. Contracts and descends
Its descent increases thoracic volume. Intrathoracic pressure falls, drawing air in.
Boyle's law explains that:
1. A. Gas moves from low to high pressure
2. B. Gases dissolve in proportion to pressure
3. C. Pressure and volume rise together
4. D. As volume rises, pressure falls
Show answer
Answer: D. As volume rises, pressure falls
It underlies the mechanics of ventilation. Gas dissolving in a liquid in proportion to its partial pressure is Henry's law, not Boyle's.
Accessory muscles of inspiration include the:
1. A. Diaphragm
2. B. Rectus abdominis
3. C. Scalenes and SCM
4. D. Internal intercostals
Show answer
Answer: C. Scalenes and SCM
SCM is the sternocleidomastoid. Their use signals increased work of breathing.
Forced exhalation involves the:
1. A. Scalene muscles
2. B. Abdominal muscles
3. C. External intercostals
4. D. Diaphragm contraction
Show answer
Answer: B. Abdominal muscles
The internal intercostals also assist. It becomes prominent in obstructive disease.
Compliance refers to:
1. A. Ease of lung expansion
2. B. Gas exchange rate
3. C. Blood oxygen content
4. D. Airway resistance
Show answer
Answer: A. Ease of lung expansion
It describes how easily the lungs and chest wall expand. Stiff lungs have low compliance.
Airway resistance increases with:
1. A. Deeper breathing
2. B. Bronchoconstriction
3. C. Bronchodilation
4. D. Larger airways
Show answer
Answer: B. Bronchoconstriction
Mucus and edema also raise resistance. Small changes in radius greatly affect resistance.
Tidal volume is defined as:
1. A. Maximum inhaled volume
2. B. Air remaining after exhalation
3. C. Total lung capacity
4. D. Air moved in a normal breath
Show answer
Answer: D. Air moved in a normal breath
It is about 5 to 7 mL/kg.
Vital capacity is:
1. A. Air in the conducting airways
2. B. Air left after full exhalation
3. C. Normal resting breath volume
4. D. Maximum exhale after maximum inhale
Show answer
Answer: D. Maximum exhale after maximum inhale
It declines with age and restrictive disease.
Functional residual capacity refers to:
1. A. Air left after a maximal exhalation
2. B. Air left after a normal exhalation
3. C. Air moved in a normal breath
4. D. Air in the conducting airways
Show answer
Answer: B. Air left after a normal exhalation
It serves as an oxygen reservoir.
Total lung capacity in an adult male averages:
1. A. 10 L
2. B. 2 L
3. C. 500 mL
4. D. 6 L
Show answer
Answer: D. 6 L
It includes residual volume.
Alveolar ventilation is calculated as:
1. A. Tidal volume x rate
2. B. Minute volume + dead space
3. C. Dead space x rate
4. D. (VT - dead space) x rate
Show answer
Answer: D. (VT - dead space) x rate
VT is tidal volume. It reflects air that actually reaches the alveoli.
A patient breathing rapidly and shallowly may have:
1. A. Improved oxygenation from the faster respiratory rate
2. B. Reduced dead space because breaths move faster
3. C. Poor alveolar ventilation from dead space
4. D. Adequate ventilation, since the fast rate offsets the shallow depth
Show answer
Answer: C. Poor alveolar ventilation from dead space
Depth matters as much as rate. Much of each shallow breath only fills anatomic dead space and never reaches the alveoli.
The partial pressure of oxygen in the atmosphere at sea level is approximately:
1. A. 21 mm Hg
2. B. 760 mm Hg
3. C. 160 mm Hg
4. D. 100 mm Hg
Show answer
Answer: C. 160 mm Hg
Roughly 21 percent of 760 mm Hg.
Normal arterial oxygen partial pressure is approximately:
1. A. 80 to 100 mm Hg
2. B. 35 to 45 mm Hg
3. C. 60 to 70 mm Hg
4. D. 150 to 160 mm Hg
Show answer
Answer: A. 80 to 100 mm Hg
Venous PO2 is around 40 mm Hg.
Normal arterial carbon dioxide partial pressure is approximately:
1. A. 35 to 45 mm Hg
2. B. 20 to 30 mm Hg
3. C. 50 to 60 mm Hg
4. D. 80 to 100 mm Hg
Show answer
Answer: A. 35 to 45 mm Hg
It correlates closely with ventilation.
Gas exchange across the alveolar membrane occurs by:
1. A. Osmosis driven by plasma proteins
2. B. Simple diffusion down pressure gradients
3. C. Active transport using cellular energy
4. D. Facilitated transport by carrier proteins
Show answer
Answer: B. Simple diffusion down pressure gradients
Oxygen moves in, carbon dioxide moves out.
Diffusion of gases is impaired by:
1. A. Fluid, fibrosis, or loss of alveolar area
2. B. A thin membrane with a large surface area
3. C. A steep partial pressure gradient
4. D. Breathing a higher oxygen concentration
Show answer
Answer: A. Fluid, fibrosis, or loss of alveolar area
Pulmonary edema and fibrosis both impair it. Thickened membranes, interstitial fluid, and lost surface area all slow diffusion.
Internal respiration refers to:
1. A. Movement of air into and out of the lungs
2. B. The mechanical work of the respiratory muscles
3. C. Gas exchange between alveoli and blood
4. D. Gas exchange between capillaries and cells
Show answer
Answer: D. Gas exchange between capillaries and cells
External respiration occurs at the alveoli.
Hypoxic drive refers to:
1. A. A stretch reflex that limits lung inflation
2. B. The breathing response to metabolic acidosis
3. C. The normal primary stimulus to breathe
4. D. A backup stimulus triggered by low oxygen
Show answer
Answer: D. A backup stimulus triggered by low oxygen
It matters in a small subset of patients with chronic CO2 retention.
Central chemoreceptors are located in the:
1. A. Aortic arch, sensing blood pressure
2. B. Medulla, sensing CSF pH from CO2
3. C. Pons, sensing lung stretch
4. D. Carotid bodies, sensing arterial oxygen
Show answer
Answer: B. Medulla, sensing CSF pH from CO2
They provide the main drive to breathe. They respond to pH changes in cerebrospinal fluid caused by carbon dioxide.
The apneustic and pneumotaxic centers are located in the:
1. A. Pons
2. B. Hypothalamus
3. C. Cerebellum
4. D. Medulla
Show answer
Answer: A. Pons
They modulate the medullary rhythm.
Cheyne-Stokes respirations are characterized by:
1. A. Crescendo-decrescendo breaths with apnea
2. B. Deep, rapid breaths at a steady regular rate
3. C. Irregular gasps separated by long pauses
4. D. Prolonged expiration through pursed lips
Show answer
Answer: A. Crescendo-decrescendo breaths with apnea
They occur with brain injury and heart failure. Breaths increase then decrease in depth, alternating with periods of apnea.
Kussmaul respirations are:
1. A. Absent, because of brainstem herniation
2. B. Deep and rapid, compensating for acidosis
3. C. Irregular, with clusters and apnea
4. D. Shallow and slow, from opioid depression
Show answer
Answer: B. Deep and rapid, compensating for acidosis
They are seen in diabetic ketoacidosis. The acidosis they compensate for is metabolic.
Agonal respirations indicate:
1. A. Deep, rapid breathing that offsets an acidosis
2. B. Anxiety-related hyperventilation
3. C. Crescendo-decrescendo cycles with apnea
4. D. Ineffective gasping, as in cardiac arrest
Show answer
Answer: D. Ineffective gasping, as in cardiac arrest
Treat them as apnea and begin ventilation. Deep, rapid breathing that compensates for acidosis is Kussmaul breathing, and crescendo-decrescendo cycles with apnea are Cheyne-Stokes respirations.
Retractions in a child indicate:
1. A. Fever-driven fast breathing alone
2. B. Significantly increased work of breathing
3. C. A compensated metabolic acidosis
4. D. Shallow splinting from the pain of a rib injury
Show answer
Answer: B. Significantly increased work of breathing
Their pliable chest wall makes them prominent. Retractions show the child is generating strong negative pressure to move air. Fever and acidosis raise the rate or depth of breathing without drawing in the chest wall, and splinting from rib pain makes breaths shallow rather than causing retractions.
Nasal flaring in an infant is a sign of:
1. A. Respiratory distress
2. B. Simple nasal congestion
3. C. Normal newborn breathing
4. D. Compensation for metabolic alkalosis
Show answer
Answer: A. Respiratory distress
It is often an early finding. Flaring widens the nostrils to lower airway resistance during labored breathing. Congestion alone does not cause it, and alkalosis is compensated by slower breathing, not increased effort.
Grunting in an infant represents:
1. A. Upper airway obstruction at the larynx
2. B. An effort to keep alveoli open
3. C. Expiratory wheezing from bronchospasm
4. D. Simple nasal congestion
Show answer
Answer: B. An effort to keep alveoli open
It suggests significant respiratory compromise. Grunting holds pressure at end expiration to keep alveoli open and signals distress. Laryngeal obstruction produces stridor, and bronchospasm produces a musical wheeze; grunting is a short sound made against a partly closed glottis.
Stridor is caused by:
1. A. Narrowing of the small bronchioles
2. B. Inflamed pleural surfaces rubbing
3. C. Upper airway narrowing or obstruction
4. D. Fluid in the alveoli and small airways
Show answer
Answer: C. Upper airway narrowing or obstruction
Croup and epiglottitis produce it.
Wheezing is produced by:
1. A. Upper airway obstruction at the larynx
2. B. Inflamed pleura rubbing together
3. C. Narrowed lower airways
4. D. Fluid filling the alveoli
Show answer
Answer: C. Narrowed lower airways
It may be expiratory, inspiratory, or both.
Crackles suggest:
1. A. Fluid in alveoli or small airways
2. B. Partial upper airway obstruction
3. C. Inflamed pleural surfaces
4. D. Bronchospasm in the lower airways
Show answer
Answer: A. Fluid in alveoli or small airways
Heart failure and pneumonia commonly produce them.
Rhonchi suggest:
1. A. Secretions in larger airways
2. B. Normal air movement in the lungs
3. C. Fluid in the alveoli
4. D. Swelling of the upper airway
Show answer
Answer: A. Secretions in larger airways
They often clear with coughing.
Absent breath sounds on one side may indicate:
1. A. Pneumothorax or a mainstem intubation
2. B. Diffuse bronchospasm from asthma
3. C. Bilateral pulmonary edema
4. D. Normal variation in chest wall thickness
Show answer
Answer: A. Pneumothorax or a mainstem intubation
Compare both sides in several locations. Hemothorax and airway obstruction are other causes.
A patient with a suspected large pulmonary embolism has clear lung sounds, SpO2 86%, and a low ETCO2. The best explanation is:
1. A. The alveoli are filled with fluid from heart failure
2. B. Ventilated alveoli have no blood flow (dead space)
3. C. The airways are narrowed by severe bronchospasm
4. D. The diaphragm is paralyzed and cannot contract
Show answer
Answer: B. Ventilated alveoli have no blood flow (dead space)
A clot blocks perfusion to lung regions that are still ventilated, which increases dead space. Little CO2 reaches those alveoli, so ETCO2 falls, and blood is diverted to other areas, so oxygenation drops. Fluid-filled alveoli would cause crackles, bronchospasm would cause wheezing, and diaphragm paralysis would reduce chest and abdominal movement.
Pneumonia causes hypoxemia primarily through:
1. A. Dead space from blocked capillaries
2. B. Reduced hemoglobin levels
3. C. Upper airway obstruction
4. D. Shunting past fluid-filled alveoli
Show answer
Answer: D. Shunting past fluid-filled alveoli
Oxygen alone may not fully correct it. Blood passes alveoli that are filled and unventilated, so it picks up no oxygen.
Chronic obstructive pulmonary disease is characterized by:
1. A. Airflow limitation with air trapping
2. B. Restricted lung expansion from stiff tissue
3. C. Reversible bronchospasm only
4. D. Reduced compliance with normal airways
Show answer
Answer: A. Airflow limitation with air trapping
Emphysema and chronic bronchitis are the main forms. Expiration is prolonged.
Emphysema damages the lungs by:
1. A. Thickening and scarring the pleura
2. B. Increasing mucus production in bronchi
3. C. Narrowing the trachea with scar tissue
4. D. Destroying alveolar walls
Show answer
Answer: D. Destroying alveolar walls
Air trapping results. This reduces surface area and elastic recoil.
Chronic bronchitis is defined by:
1. A. Episodic reversible bronchospasm
2. B. A chronic productive cough
3. C. Recurrent pleural fluid buildup
4. D. Destruction of alveolar walls
Show answer
Answer: B. A chronic productive cough
Patients often retain carbon dioxide. Airway inflammation and excess mucus drive the cough.
Asthma involves:
1. A. Progressive loss of alveolar walls
2. B. Reversible bronchospasm and inflammation
3. C. Permanent destruction of airway walls
4. D. Fluid accumulating in the pleural space
Show answer
Answer: B. Reversible bronchospasm and inflammation
Triggers vary among patients. Mucus production also contributes.
A silent chest in a severe asthma attack means:
1. A. The bronchospasm has resolved on its own
2. B. Air is moving well, so no wheeze forms
3. C. The airways have filled with fluid
4. D. Airflow is too poor to make wheezes
Show answer
Answer: D. Airflow is too poor to make wheezes
Prepare to ventilate. It is a critical sign. Wheezing needs airflow, so a quiet chest in a struggling asthmatic means little air is moving. It is not caused by fluid filling the airways.
Pulmonary edema impairs gas exchange by:
1. A. Reducing circulating hemoglobin
2. B. Fluid between alveoli and capillaries
3. C. Blocking the trachea with froth
4. D. Constricting the bronchi through spasm
Show answer
Answer: B. Fluid between alveoli and capillaries
Cardiogenic causes are the most common.
Hypoventilation produces:
1. A. Metabolic acidosis
2. B. Respiratory alkalosis
3. C. Respiratory acidosis
4. D. No acid-base change
Show answer
Answer: C. Respiratory acidosis
Ventilate, rather than simply adding oxygen. Carbon dioxide rises.
Hyperventilation lowers carbon dioxide, which causes cerebral:
1. A. Vasoconstriction and reduced flow
2. B. Vasodilation with brain swelling
3. C. No change in cerebral blood flow
4. D. Vasodilation and increased blood flow
Show answer
Answer: A. Vasoconstriction and reduced flow
This is why routine hyperventilation in head injury is harmful.
Oxygen saturation of 90 percent corresponds to an approximate arterial oxygen partial pressure of:
1. A. About 100 mm Hg
2. B. About 150 mm Hg
3. C. About 40 mm Hg
4. D. About 60 mm Hg
Show answer
Answer: D. About 60 mm Hg
Below that point, small saturation drops reflect large PO2 drops.
A patient pulled from a house fire has an SpO2 of 99% on a standard pulse oximeter. Why can this reading be misleading?
1. A. Carbon monoxide shifts the oxyhemoglobin curve to the right
2. B. Standard oximeters read carboxyhemoglobin as oxygenated
3. C. Carbon monoxide raises the PaO2 reading in blood
4. D. Smoke-induced bronchospasm raises the saturation
Show answer
Answer: B. Standard oximeters read carboxyhemoglobin as oxygenated
CO binds hemoglobin far more tightly than oxygen, and standard two-wavelength oximeters cannot tell carboxyhemoglobin from oxyhemoglobin, so SpO2 reads falsely normal. CO-oximetry is needed to measure it. CO reduces oxygen delivery and shifts the curve left. PaO2 can be normal because dissolved oxygen is unaffected. Bronchospasm, if present, lowers rather than raises oxygen saturation.
The primary difference between ventilation and oxygenation is that oxygenation refers to:
1. A. Rising and falling of the chest wall
2. B. Loading oxygen and delivering it
3. C. Removing carbon dioxide from blood
4. D. Moving air in and out of the lungs
Show answer
Answer: B. Loading oxygen and delivering it
A patient may be oxygenated yet still hypoventilating. Oxygenation means loading oxygen into the blood and delivering it to tissues.
Infants and children are more prone to airway obstruction because they have:
1. A. Fewer and thinner airway secretions
2. B. Larger airways relative to body size
3. C. Stiffer, less compliant chest walls
4. D. Larger tongues and smaller airways
Show answer
Answer: D. Larger tongues and smaller airways
Small amounts of swelling narrow the airway significantly. Their airway structures are also more flexible.
The narrowest portion of a young child's airway has traditionally been described as the:
1. A. Cricoid ring
2. B. Nasal passage
3. C. Carina
4. D. Glottic opening
Show answer
Answer: A. Cricoid ring
Recent evidence suggests the difference is less pronounced than once taught.
Aging affects the respiratory system by:
1. A. Improving alveolar gas exchange
2. B. Reducing vital capacity and cough
3. C. Increasing ciliary activity
4. D. Increasing vital capacity and lung recoil
Show answer
Answer: B. Reducing vital capacity and cough
Pneumonia risk rises accordingly. The chest wall also stiffens.
Hypoxia is best detected clinically by:
1. A. A single pulse oximetry reading
2. B. Lung sounds heard on auscultation
3. C. Mental status, skin, effort, and SpO2
4. D. The respiratory rate in isolation
Show answer
Answer: C. Mental status, skin, effort, and SpO2
Restlessness is often the earliest sign.
The respiratory system contributes to acid-base balance by:
1. A. Converting lactic acid back to glucose
2. B. Excreting hydrogen ions in urine
3. C. Producing bicarbonate in the lungs
4. D. Adjusting CO2 elimination
Show answer
Answer: D. Adjusting CO2 elimination
It is the fast compensation mechanism. Changes in ventilation adjust carbon dioxide within minutes. Converting lactate back to glucose is done by the liver.
The upper airway's protective reflexes include:
1. A. Bronchodilation and sighing
2. B. Cough, gag, and laryngospasm
3. C. Yawning, sighing, and hiccups
4. D. Hiccups and snoring
Show answer
Answer: B. Cough, gag, and laryngospasm
Sedation and unconsciousness impair them.
Laryngospasm refers to:
1. A. Spasm of the bronchial smooth muscle
2. B. Reflex closure of the vocal cords
3. C. Collapse of the tracheal rings
4. D. Swelling of the epiglottis
Show answer
Answer: B. Reflex closure of the vocal cords
It can occur during airway manipulation.
Suctioning should be limited in duration because it:
1. A. Removes oxygen and can slow the heart
2. B. Wastes time needed for transport
3. C. Pushes secretions deeper into the lungs
4. D. Causes the lungs to overinflate
Show answer
Answer: A. Removes oxygen and can slow the heart
Preoxygenate and limit each attempt. Suction removes oxygen along with secretions, and stimulation of the pharynx can trigger a vagal response that slows the heart. Clearing the airway is part of care rather than wasted transport time, suction draws secretions out rather than deeper, and its negative pressure tends to collapse alveoli rather than overinflate them.
A patient with a tracheostomy breathes:
1. A. Through the nose only
2. B. Through the mouth only
3. C. Through the vocal cords
4. D. Through the stoma
Show answer
Answer: D. Through the stoma
Humidification and suction are important for them. The stoma bypasses the upper airway.
Which statement about oxygen delivery to tissues is accurate?
1. A. Output, hemoglobin, and SpO2 all matter
2. B. Hemoglobin level has little effect
3. C. Saturation alone determines delivery
4. D. Perfusion matters less than saturation
Show answer
Answer: A. Output, hemoglobin, and SpO2 all matter
A severely anemic patient may be hypoxic at full saturation. Delivery depends on cardiac output, hemoglobin, and saturation together.

Respiratory System Practice Questions

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