Question 1

Compliance is BEST explained by which of the following statements.

Accepted Answer

Compliance of lung tissue is likened to a balloon during inspiration,where there exists a tendency to collapse or recoil while inflated.A = elasticity;B = surface tension;D = transmural pressure.

Question 2

Which of the following BEST describes the intrapleural pressure compared to the intrapulmonary pressure?

Accepted Answer

The intrapleural pressure is normally lower than the intrapulmonary pressure developed during both inspiration and expiration.This difference in pressures helps to maintain the lung near the chest wall.

Question 3

Which of the following statements BEST explains why increasing administered oxygen should be done cautiously in a patient with severe chronic obstructive pulmonary disease (COPD)AT REST?

Accepted Answer

A patient with severe COPD who develops high CO₂ blood levels subsequently leads to the body relying more on oxygen receptors instead of carbon dioxide receptors.This is termed hypoxic drive to breathe.If administered oxygen is too high and causes hyperoxemia (increased oxygen in the blood),the oxygen receptors may be suppressed,which reduces the drive to breathe.

Question 4

Which of the following lung receptors are stimulated in a patient with left-sided congestive heart failure who develops pulmonary edema causing the patient to breathe in a SHALLOW,tachypneic pattern.

Accepted Answer

The juxtapulmonary receptors (J receptor)are located near the pulmonary capillaries and are sensitive to increased pulmonary capillary pressures.On stimulation,these receptors initiate a rapid,shallow breathing pattern.In a patient with congestive heart failure,pulmonary edema would stimulate the interstitial J receptors.

Question 5

Which of the following improves gas exchange in the base of the lungs?

Accepted Answer

A change in the position of the patient changes areas of ventilation and perfusion.Generally,greater ventilation and perfusion occur in gravity-dependent areas,thereby allowing better respiration to occur in the dependent lung.The upright sitting position would facilitate better ventilation/perfusion matching in the base of the lungs due to gravity dependency.

Question 6

In the systemic arteries,at a partial pressure of 100 mm Hg,the percent of hemoglobin should be:

Accepted Answer

In the systemic arteries,at a partial pressure of 100 mm Hg,the percent of hemoglobin is 97% indicating that 97% of hemoglobin molecules in blood are bound to oxygen.The remaining 3% reflects deoxyhemoglobin,methemoglobin,and carboxyhemoglobin concentrations.

Question 7

Which of the following is the BEST way to measure oxyhemoglobin saturation?

Accepted Answer

The gold standard or best test for measuring oxyhemoglobin saturation is through an analysis of arterial blood gases.Pulse oximeter can also be utilized to obtain this number,but is less accurate due to it being an estimation and not a direct measure.

Question 8

The total volume of air that is inhaled or exhaled in 1 minute is termed:

Accepted Answer

The minute ventilation represents the total volume of air that is inhaled or exhaled in 1 minute.

Question 9

Which of the following events occur as a result of the diaphragm and external intercostals contracting to facilitate inspiration?

Accepted Answer

When the diaphragm and external intercostals contract to facilitate inspiration,it causes an increase in the volume of the thoracic cavity and lung,which reduces the intrapulmonary pressure.The intrapulmonary pressure is decreased below the atmospheric levels facilitating the flow of air into the lungs to normalize pressure differences.

Question 10

Which of the following factors act to decrease airway resistance?

Accepted Answer

Sympathetic nervous system influence decreases airway resistance,which would be congruent with the need to improve airflow in order to keep up with the body's demand for oxygen during exercise.Poiseuille's law states that the flow through a vessel or airway is directly proportional to the pressure difference and radius and inversely proportional to the length of the airway and viscosity of the gas.Small changes in radius account for large changes in airflow.

Question 11

Which of the following changes in the system would cause a shift in the oxyhemoglobin dissociation curve to the left?

Accepted Answer

An increase in pH or alkalemia would shift the curve to the left.Answer choices B,C,and D all shift the curve to the right.

Question 12

Which of the following statements is MOST correct about surfactant?

Accepted Answer

Surfactant is a surface-active agent that is needed to decrease the overall surface tension of alveoli in order to lower wall tension in proportion to the radius of the alveolus.Pressure within the alveolus is directly proportional to the surface tension and inversely proportional to the radius of the alveolus.The availability of surfactant assists in keeping air in alveoli of varying sizes.

Question 13

Which of the following forms of hemoglobin molecules refers to the binding of heme to carbon monoxide instead of oxygen?

Accepted Answer

Carboxyhemoglobin is another form of hemoglobin that involves the binding of heme to carbon monoxide instead of oxygen.The bond with carbon monoxide is 210 times stronger than oxygen,and therefore displaces oxygen and inhibits its binding capacity.

Question 14

The maximum amount of air that can be inhaled after a normal tidal exhalation is termed:

Accepted Answer

The inspiratory capacity (IC)is the sum of the tidal and inspiratory reserve volumes;it is the maximum amount of air that can be inhaled after a normal tidal exhalation.

Question 15

To facilitate the diffusion of oxygen from alveoli to pulmonary capillary,which of the following must occur?

Accepted Answer

For gas exchange to occur,a pressure gradient must be created across the alveolar capillary interface.This gradient will enable gases to diffuse from an area of high concentration to areas of low concentration across the semipermeable respiratory membrane.

Question 16

Which of the following lung tissue receptors are located along the smooth muscles lining the airways are sensitive to increasing size and volume within the lung,termed the Hering-Breuer reflex?

Accepted Answer

Stretch receptors are located along smooth muscles lining the airways and are sensitive to increasing size and volume within the lung.The Hering-Breuer reflex is active with large increases in the tidal volume,especially seen during exercise,and protects the lung from excessive inflation.

Question 17

Which of the following physical properties of lungs facilitates passive expiration?

Accepted Answer

Elasticity refers to the tendency of a structure to return to its initial size after being distended.This elastic recoil of the lung allows passive expiration to occur.

Question 18

Which of the following brain areas provides control for automatic breathing?

Accepted Answer

The medulla oblongata contains inspiratory neurons that produce inspiration and expiratory neurons that are triggered with force expiration.These neurons control automatic breathing.

Question 19

The primary function of the pulmonary system is which of the following?

Accepted Answer

According to the author,the most important function of the pulmonary system is to exchange oxygen and carbon dioxide between the environment,blood,and tissue.

Question 20

Which of the following factors will potentially diminish cardiac output?

Accepted Answer

Beta-blocker medications blunt heart rate response during exercise by making the beta-receptors on the myocardial wall unresponsive to sympathetic stimulation and appropriately increase heart rate.A lack of heart rate response would potentially diminish cardiac output.

Quiz 2: Physiology of the Cardiovascular and Pulmonary Systems