Question 1

How does the lung parenchyma receive most of its O₂? A) From the alveolar gases B) From the bronchial arteries/capillaries C) From the pulmonary arteries/capillaries D) From the pulmonary lymphatic system

Accepted Answer

A separate arterial supply called the bronchial circulation supplies blood to the airways from the trachea to the bronchioles and to most of the visceral pleurae.The metabolic needs of the lung are comparatively low, and much of the lung parenchyma is oxygenated by direct contact with inspired gas.

Question 2

Via what pathway does much of the bronchial venous drainage occur?
A) Bronchial veins emptying into the inferior vena cava
B) Bronchopulmonary veins emptying into pulmonary veins
C) Direct connections between bronchial and pulmonary arteries
D) Thebesian venous drainage into the heart chambers

Accepted Answer

Bronchial venous blood drains through the azygos, hemiazygos, and intercostal veins to the right atrium, and some drains through the pulmonary capillaries to the pulmonary veins and to the left atrium.

Question 3

Which of the following statements is/are true of the pulmonary lymphatic system?
1) It consists of both superficial and deep vessels.
2) It drains into the right lymphatic or thoracic duct.
3) Vessels begin as dead-end lymphatic channels in the lung.
4) With phagocytes, it defends against foreign material.
A)1, 3, and 4 only
B)2, 3, and 4 only
C)2 only
D)1, 2, 3, and 4

Accepted Answer

The pulmonary lymphatic system indeed consists of both superficial and deep vessels, drains into the right lymphatic or thoracic duct, begins as dead-end lymphatic channels in the lung, and contains phagocytes that help defend against foreign material.

Question 4

Compared with the systemic circulation under normal conditions, pressure in the pulmonary circulation is:
A) higher.
B) lower.
C) the same.
D) not connected.

Accepted Answer

While the entire cardiac output passes through both pulmonary and systemic circuits, the pulmonary circulation offers much lower resistance and, as a result, has a much lower blood pressure.

Question 5

The pulmonary venous circulation does which of the following?
1) Delivers oxygenated blood back to the heart.
2) Delivers deoxygenated blood to the lungs.
3) Empties into the left atrium.
4) Empties into the right atrium.
A)2 and 3 only
B)1 and 4 only
C)2 and 4 only
D)1 and 3 only

Accepted Answer

The pulmonary venous circulation delivers oxygenated blood back to the heart (1) and empties into the left atrium (3). It does not deliver deoxygenated blood to the lungs (2) or empty into the right atrium (4).

Question 6

What is the name of the reflex associated with the sensory stimulation of the pulmonary stretch receptors that stimulates a deeper breath upon inspiration?
A) Carotid sinus
B) Head's paradoxical
C) Hering-Breuer
D) Vagovagal

Accepted Answer

Another reflex that is associated with stretch receptor activity is head's paradoxical reflex.This reflex stimulates a deeper breath rather than inhibiting further inspiration. It may be the basis for occasional deep breaths or gasps. Deep breaths or sighs occur with normal breathing, presumably preventing alveolar collapse. Head's reflex may also be responsible for gasping in newborn infants as they progressively inflate their lungs.

Question 7

What does the detection of lymphatic channels on standard chest radiographs indicate?
A) Abnormally low pressures in the lymphatic channels
B) Anastomoses with the pulmonary circulation
C) Normal fibrotic changes that occur with aging
D) System that is overwhelmed by excessive fluid

Accepted Answer

Lymphatic channels are usually not visible on chest radiographs. They may be detected if they are distended or thickened by disease. The "butterfly" pattern that radiates from the hilar region of both lungs during acute development of pulmonary edema is thought to largely be the result of interstitial and lymph vessel distension with fluid. In this situation, the lymphatic drainage system has been overwhelmed by a sudden and excessive surge of fluid from the circulation. The development of a pleural effusion is also evidence that the lymphatic system is unable to remove excess fluid in the lung.

Question 8

How would lung perfusion in a "zone 1" area best be described?
A) Increased
B) Normal or average
C) Reduced
D) Unaffected

Accepted Answer

Areas that experience higher airway pressure (e.g., during positive pressure ventilation) that equal or exceed local arteriole and capillary pressure will have reduced blood flow as a result of the opposing airway pressure (zone 1 airways).

Question 9

Which of the following statements is false regarding the pulmonary circulation?
A) Pulmonary blood flow is highly dependent on gravity.
B) The pulmonary circulation is a low-pressure system.
C) Toward the top of the upright lung, blood flow is high.
D) Toward the top of the upright lung, blood flow is low.

Accepted Answer

As a consequence of having a low blood pressure and being susceptible to gravity, blood flow is much higher in the lung bases in resting upright subjects. Gravity-related effects also occur in recumbent positions but are less pronounced.

Question 10

What is the primary mechanism that stops the lungs from collapsing at the end of exhalation?
A) Radial tethers, stretched to their maximum length, then halt lung collapse.
B) Surfactant neutralizes the tendency of the lung to collapse.
C) There is a tendency of the chest wall to lock at the level of FRC.
D) There is an equal opposing tendency of the chest wall to expand.

Accepted Answer

This tendency of the lung to collapse is counteracted by the thoracic wall's tendency to spring outward and to hold the lung inflated.

Question 11

Which of the following describes a function of pulmonary circulation?
A) Breakdown of angiotensin II
B) Filtering of blood clots
C) Production of erythropoietin
D) Regulation of breathing

Accepted Answer

The third function is nonrespiratory and participates in the production, processing, and clearance of a large variety of chemicals and blood clots.

Question 12

What determines the airway diameter in the normal lung?
A) Balance between sympathetic and parasympathetic tone
B) In large part, the amount of patient effort
C) Activity level of the submucosal glands
D) Amount of dopamine present in the airway walls

Accepted Answer

Both sympathetic and parasympathetic postganglionic efferents innervate the smooth muscle and glands of the airways. They influence the diameter of the airway by causing more or less tension in the smooth muscles that wrap the airway and influence glandular secretion. The combined effects of the parasympathetic and sympathetic nervous activity, which generally oppose each other's action, result in a balanced control of airway diameter.

Question 13

What is the effect of damage to the recurrent laryngeal nerves?
A) Diaphragmatic paralysis
B) Pulmonary circulatory failure
C) Inactivation of pulmonary surfactant production
D) Vocal cord impairment or paralysis

Accepted Answer

Damage to laryngeal nerves can cause unilateral or bilateral vocal cord paralysis, depending on which branches are involved. This may result in hoarseness, loss of voice, and an ineffective cough.

Question 14

How does the lung respond to regional lung hypoxia?
A) Bronchial artery vasoconstriction
B) Bronchial artery vasodilation
C) Pulmonary artery vasoconstriction
D) Pulmonary artery vasodilation

Accepted Answer

Areas of regional lung hypoxia, as the result of reduced ventilation, congestion, and/or airway obstruction, can result in local pulmonary arterial vasoconstriction and cause blood flow to be shifted from these areas toward areas of higher O₂ content and pulmonary vasodilation.

Question 15

How does the body compensate for a pulmonary embolus that occludes a branch of the pulmonary artery?
A) Increased bronchial arterial flow to the area
B) Increased cardiac output
C) Pulmonary arteriole and metarteriole vasodilation
D) Release of prostaglandins to fight inflammation

Accepted Answer

The bronchial and pulmonary circulations share an important compensatory relationship.Decreased pulmonary arterial blood pressure tends to cause an increase in bronchial artery blood flow to the affected area. This minimizes the danger of pulmonary infarction, as sometimes occurs when a blood clot (pulmonary embolus) enters the lung.

Question 16

Fluid transport to and from the lungs is provided by which of the following?
1) Bronchial circulation
2) Lymphatic system
3) Pulmonary circulation
A)2 and 3 only
B)1 and 3 only
C)2 only
D)1, 2, and 3

Accepted Answer

The bronchial circulation supplies nutrients and oxygen to the lung tissue, the lymphatic system helps in removing excess fluid and proteins from the interstitial spaces, and the pulmonary circulation is responsible for gas exchange and transporting blood to and from the lungs.

Question 17

What forces establish the sub-atmospheric pressure found in the pleural space?
A) Contraction of accessory muscles of inspiration
B) Contraction of expiratory muscles
C) Equal opposing tendency of the chest wall to expand and lung to collapse
D) Effect of gravity, particularly at the base of the lungs

Accepted Answer

This tendency of the lung to collapse is counteracted by the thoracic wall's tendency to spring outward and to hold the lung inflated. The "tension" developed by these two opposing tendencies results in development of sub-atmospheric intrapleural pressure.

Question 18

What is the name of the negative feedback reflex associated with the termination of inspiration?
A) Carotid sinus
B) Head's paradoxical
C) Hering-Breuer
D) Vagovagal

Accepted Answer

Pulmonary stretch receptors progressively discharge during lung inflation and are linked to inhibition of further inflation. This is a type of negative feedback known as the inflation reflex or the Hering-Breuer inflation reflex.

Question 19

The pulmonary arterial circulation does which of the following?
1) Delivers oxygenated blood back to the heart.
2) Delivers deoxygenated blood to the lungs.
3) Originates on the left side of the heart.
4) Originates on the right side of the heart.
A)1 and 4 only
B)2 and 4 only
C)1 and 3 only
D)2 and 3 only

Accepted Answer

The pulmonary arterial circulation delivers deoxygenated blood to the lungs and originates on the right side of the heart. It is important to note that oxygenated blood returns to the heart via the pulmonary veins, not the pulmonary arteries. Therefore, option 1 is incorrect. The pulmonary artery is the only artery that carries deoxygenated blood, and it originates on the right ventricle of the heart, hence option 4 is correct. Option 3 is incorrect because pulmonary circulation originates on the right side of the heart, not the left.

Question 20

Pressures in the pulmonary circulation are lower than those in the systemic circulation because of what characteristic of the pulmonary circulation?
A) Higher resistance than the systemic circulation
B) Less blood flow than the systemic circulation
C) Lower resistance than the systemic circulation
D) More blood flow than the systemic circulation

Accepted Answer

While the entire cardiac output passes through both pulmonary and systemic circuits, the pulmonary circulation offers much lower resistance and, as a result, has a much lower blood pressure.

Quiz 9: The Respiratory System

How does the lung parenchyma receive most of its O2?

Via what pathway does much of the bronchial venous drainage occur?

Compared with the systemic circulation under normal conditions, pressure in the pulmonary circulation is:

The pulmonary venous circulation does which of the following? 1) Delivers oxygenated blood back to the heart. 2) Delivers deoxygenated blood to the lungs. 3) Empties into the left atrium. 4) Empties into the right atrium.

What is the name of the reflex associated with the sensory stimulation of the pulmonary stretch receptors that stimulates a deeper breath upon inspiration?

What does the detection of lymphatic channels on standard chest radiographs indicate?

How would lung perfusion in a "zone 1" area best be described?

Which of the following statements is false regarding the pulmonary circulation?

What is the primary mechanism that stops the lungs from collapsing at the end of exhalation?

Which of the following describes a function of pulmonary circulation?

What determines the airway diameter in the normal lung?

What is the effect of damage to the recurrent laryngeal nerves?

How does the lung respond to regional lung hypoxia?

How does the body compensate for a pulmonary embolus that occludes a branch of the pulmonary artery?

Fluid transport to and from the lungs is provided by which of the following? 1) Bronchial circulation 2) Lymphatic system 3) Pulmonary circulation

What forces establish the sub-atmospheric pressure found in the pleural space?

What is the name of the negative feedback reflex associated with the termination of inspiration?

The pulmonary arterial circulation does which of the following? 1) Delivers oxygenated blood back to the heart. 2) Delivers deoxygenated blood to the lungs. 3) Originates on the left side of the heart. 4) Originates on the right side of the heart.

Pressures in the pulmonary circulation are lower than those in the systemic circulation because of what characteristic of the pulmonary circulation?

How does the lung parenchyma receive most of its O₂?