1.
Moving inspired air into close proximity to the pulmonary capillary bed to enable gas exchange is the principle of:
Correct Answer
A. Simple diffusion
Explanation
The principle of simple diffusion involves the movement of inspired air into close proximity to the pulmonary capillary bed to enable gas exchange. This process occurs passively, without the need for energy or a carrier molecule. The concentration gradient between the alveoli and the capillaries allows for the exchange of gases, such as oxygen and carbon dioxide, across the thin respiratory membrane. This principle is essential for efficient gas exchange in the lungs.
2.
The forces needed to cause the air to flow are first initiated by:
Correct Answer
C. The CNS
Explanation
The correct answer is the CNS. The central nervous system (CNS) is responsible for initiating the forces needed to cause the air to flow during respiration. It controls the respiratory muscles, which contract and relax to create the necessary pressure changes in the lungs. The CNS also regulates the rate and depth of breathing in response to various stimuli, ensuring a proper balance of oxygen and carbon dioxide in the body.
3.
Which of the following is the site of gas exchange in the lung?
Correct Answer
B. Alveoli
Explanation
The alveoli are the site of gas exchange in the lung. These tiny air sacs are located at the end of the bronchioles and are surrounded by capillaries. Oxygen from the inhaled air diffuses across the thin walls of the alveoli into the bloodstream, while carbon dioxide, a waste product, diffuses from the bloodstream into the alveoli to be exhaled. This exchange of gases is essential for respiration and providing oxygen to the body's cells. The conducting airways, bronchioles, and tertiary bronchi are involved in transporting air to and from the alveoli but do not directly participate in gas exchange.
4.
Which vessel is responsible for providing blood to the bronchial wall?
Correct Answer
D. Bronchial arteries
Explanation
The bronchial arteries are responsible for providing blood to the bronchial wall. These arteries branch off from the systemic circulation, specifically from the thoracic aorta, and supply oxygenated blood to the bronchial tissues. The pulmonary arteries, on the other hand, are responsible for carrying deoxygenated blood from the heart to the lungs for oxygenation. The pulmonary capillaries are the site of gas exchange in the lungs, where oxygen is taken up and carbon dioxide is released. Therefore, the correct answer is bronchial arteries.
5.
Which of the following is true about the pulmonary lymphatic system?
Correct Answer
A. Branches do not penetrate the alveolar wall
Explanation
The pulmonary lymphatic system refers to the network of lymphatic vessels in the lungs. These vessels collect excess fluid and waste products from the lung tissue and transport them back to the bloodstream. The correct answer states that the branches of the pulmonary lymphatic system do not penetrate the alveolar wall. This means that the lymphatic vessels do not extend into the tiny air sacs called alveoli, which are the primary sites of gas exchange in the lungs. Instead, the lymphatic vessels are located in the interstitial spaces between the alveoli and other lung structures.
6.
Which type of efferent lung fiber mediates bronchoconstriction, vasodilation and mucous gland secretion?
Correct Answer
B. Parasympathetic
Explanation
Parasympathetic efferent lung fibers are responsible for mediating bronchoconstriction, vasodilation, and mucous gland secretion. These fibers release acetylcholine, which binds to muscarinic receptors on smooth muscle cells in the bronchi, causing them to contract and narrow the airways. This leads to bronchoconstriction. Parasympathetic stimulation also causes vasodilation of blood vessels in the lungs, increasing blood flow. Additionally, it stimulates the secretion of mucus by the mucous glands in the airways, which helps to trap and remove foreign particles.
7.
Which of the following is an important mediator of sympathetic efferent fibers of the lung?
Correct Answer
D. NorepinepHrine
Explanation
Norepinephrine is an important mediator of sympathetic efferent fibers of the lung. It is released by sympathetic nerve endings and acts as a neurotransmitter. Norepinephrine binds to adrenergic receptors in the lung, causing bronchodilation and increased airflow. This helps in the fight or flight response, where the body prepares for physical activity or stress by increasing the oxygen supply to the lungs.
8.
The majority (75%) of COPD cases are diagnosed as:
Correct Answer
A. Chronic bronchitis
Explanation
Chronic bronchitis is the correct answer because it is the most common form of chronic obstructive pulmonary disease (COPD). COPD is a progressive lung disease characterized by airflow limitation. Chronic bronchitis is defined by a chronic cough and excessive mucus production in the bronchial tubes. It is often caused by long-term exposure to irritants such as cigarette smoke. Asthma, emphysema, and lung fibrosis are also respiratory conditions, but they are not the primary diagnoses associated with the majority of COPD cases.
9.
The principal cause of disease in patients with COPD is:
Correct Answer
D. Smoking
Explanation
Smoking is the principal cause of disease in patients with COPD because it damages the airways and lung tissue. The harmful chemicals in tobacco smoke irritate and inflame the airways, leading to chronic bronchitis and emphysema. Smoking also impairs the lungs' ability to clear mucus and fight off infections, further worsening the condition. Long-term smoking increases the risk of developing COPD significantly, and quitting smoking is the most effective way to slow down the progression of the disease.
10.
The primary pathologic defect in emphysema is in the:
Correct Answer
A. Respiratory unit walls
Explanation
Emphysema is a lung condition characterized by the destruction of the respiratory unit walls, specifically the alveoli. This destruction leads to the enlargement of the air spaces and a decrease in the surface area available for gas exchange. As a result, the lungs lose their elasticity and the ability to effectively transfer oxygen into the bloodstream. This explanation aligns with the understanding of emphysema as a disease primarily affecting the respiratory unit walls.
11.
A common consequence of diffuse parenchymal lung disease is:
Correct Answer
C. Lung fibrosis
Explanation
Diffuse parenchymal lung disease refers to a group of lung disorders that cause inflammation and scarring of the lung tissue. One common consequence of this condition is lung fibrosis, which is the formation of excessive scar tissue in the lungs. This fibrosis can lead to a progressive decline in lung function, making it difficult for the lungs to properly oxygenate the blood. Emphysema, pneumonia, and asthma are not typically associated with diffuse parenchymal lung disease.
12.
Which type of receptor is found on the organs that are stimulated by sympathetic fibers using norepinephrine?
Correct Answer
A. Adrenergic
Explanation
Adrenergic receptors are found on the organs that are stimulated by sympathetic fibers using norepinephrine. These receptors are activated by the neurotransmitter norepinephrine, which is released by sympathetic nerve fibers. Adrenergic receptors are further classified into alpha and beta receptors, each having different effects on the target organ. Activation of adrenergic receptors leads to the "fight or flight" response, increasing heart rate, dilating blood vessels, and increasing blood pressure.
13.
Which neurotransmitter is typically cosecreted with norephinephrine?
Correct Answer
B. Neuropeptide Y
Explanation
Neuropeptide Y is typically cosecreted with norepinephrine. Neuropeptide Y is a neurotransmitter that is involved in regulating various physiological processes such as appetite, stress response, and blood pressure. It is often released alongside norepinephrine in the sympathetic nervous system, where they work together to modulate the body's response to stress and regulate energy balance. This co-release of neuropeptide Y and norepinephrine allows for a coordinated and integrated response to physiological and environmental challenges.
14.
Vagal fibers from juxtacapillary receptors are:
Correct Answer
C. Unmyelinated and respond to chemical & mechanical stimuli
Explanation
The correct answer is "unmyelinated and respond to chemical & mechanical stimuli". Vagal fibers from juxtacapillary receptors are unmyelinated, meaning they lack a protective covering, and they are sensitive to both chemical and mechanical stimuli. This means that they can respond to various types of stimuli in the body, allowing for the transmission of information and the initiation of appropriate responses.
15.
Which represents the equilibrium point where the elastic recoil of the lung (tendency to collapse inward) and the chest wall (tendency to spring outward) are exactly balanced?
Correct Answer
A. Functional residual capacity
Explanation
The functional residual capacity represents the equilibrium point where the elastic recoil of the lung and the chest wall are balanced. At this point, the tendency of the lung to collapse inward (due to elastic recoil) is exactly counteracted by the tendency of the chest wall to spring outward. This results in a stable state where the lung is neither fully expanded nor fully collapsed, allowing for efficient gas exchange during respiration. The other options (residual volume, total lung capacity, and expiratory reserve volume) do not specifically represent this equilibrium point.
16.
Which type of airflow often occurs at branch points or points distal to partial obstructions?
Correct Answer
B. Transitional
Explanation
Transitional airflow often occurs at branch points or points distal to partial obstructions. This type of airflow is characterized by a mixture of laminar and turbulent flow patterns. It occurs when the flow is disrupted by obstacles or changes in the geometry of the airway. Transitional airflow is intermediate between laminar and turbulent flow, and it is commonly observed in areas where there are irregularities or narrowing of the airway.
17.
The majority of airflow resistance to normal breathing arises in:
Correct Answer
A. Segmental bronchi
Explanation
The majority of airflow resistance to normal breathing arises in the segmental bronchi. This is because the segmental bronchi are the first branches of the bronchial tree, and as the air passes through these branches, it encounters the highest resistance due to the smaller diameter of the bronchi. As the air continues to move through the bronchial tree, the resistance decreases in the secondary bronchi, lobar bronchi, and finally in the alveoli where gas exchange occurs.
18.
In disease states that increase elastic forces (eg. pulmonary fibrosis), total work is minimized by:
Correct Answer
A. Rapid, shallow breathing
Explanation
In disease states that increase elastic forces, such as pulmonary fibrosis, the lungs become stiff and less compliant. This means that it requires more effort to expand the lungs and overcome the increased elastic forces. Rapid, shallow breathing allows for quick inhalation and exhalation with minimal lung expansion, reducing the work done against the increased elastic forces. Slow, deep breathing would require more effort to fully expand the lungs and would therefore increase the work done. Rapid, deep breathing would also require more effort and may not be as efficient in minimizing the work. Slow, shallow breathing would not provide enough ventilation and may lead to inadequate oxygenation. Therefore, rapid, shallow breathing is the most effective strategy to minimize work in disease states with increased elastic forces.
19.
In disease states with increased airflow resistance (eg, chronic bronchitis), total work is minimized by:
Correct Answer
B. Slow, deep breathing
Explanation
In disease states with increased airflow resistance, such as chronic bronchitis, the airways are narrowed, making it difficult for air to flow in and out of the lungs. Slow, deep breathing allows for a longer inspiratory phase, which helps to overcome the increased resistance and allows for a more efficient exchange of oxygen and carbon dioxide. This type of breathing also helps to reduce the work of breathing by allowing for a longer expiratory phase, which prevents air trapping in the lungs. Therefore, slow, deep breathing minimizes the total work required to breathe in these disease states.
20.
Which of the following is an example of a pathologic state that may result from an decrease in compliance?
Correct Answer
B. Fibrosis
Explanation
Fibrosis is an example of a pathologic state that may result from a decrease in compliance. Decreased compliance refers to the stiffness or reduced ability of a tissue or organ to expand or stretch. Fibrosis is a condition characterized by the excessive formation of fibrous connective tissue, leading to the thickening and stiffening of the affected area. This can reduce the compliance of the affected organ or tissue, impairing its normal function.