Gas Exchange and Blood Supply of Lungs

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What is the primary function of the blood-air barrier in the lungs?

To prevent air bubbles from forming in the blood and blood from entering the alveoli (correct)
To filter out bacteria and particles from the air
To facilitate the exchange of oxygen and carbon dioxide
To regulate blood pressure in the pulmonary circulation

What is the approximate diffusion distance for oxygen and carbon dioxide in the pulmonary capillaries?

Five times the diameter of a red blood cell
The diameter of a red blood cell
Less than the diameter of a red blood cell (correct)
Twice the diameter of a red blood cell

What is the role of elastic fibers in the pulmonary interstitial space?

To maintain lung elasticity and prevent collapse (correct)
To filter out bacteria and particles from the air
To facilitate the exchange of oxygen and carbon dioxide
To regulate blood pressure in the pulmonary circulation

What is the origin of pulmonary macrophages?

Monocytes that have escaped from the blood capillaries (B) Signup and view all the answers

What is the purpose of the anastomosis between the bronchial and pulmonary capillary beds?

To ensure a constant supply of oxygenated blood to the lungs (D) Signup and view all the answers

What is the thickness of the blood-air barrier in the lungs?

0.2 to 2.5 µm (D) Signup and view all the answers

What is the primary function of the 'air-blood barrier' in the lungs?

To facilitate gas exchange between the alveolus and pulmonary capillaries (A) Signup and view all the answers

What is the approximate total surface area of the alveoli in both lungs?

70 m2 (C) Signup and view all the answers

What is the primary role of Type II alveolar cells?

To secrete a surfactant (A) Signup and view all the answers

How many alveoli are approximately found in each lung?

300 to 400 million (D) Signup and view all the answers

What is the characteristic shape of Type I alveolar cells?

Squamous (C) Signup and view all the answers

What percentage of the total alveolar surface area is covered by Type I alveolar cells?

95% (D) Signup and view all the answers

What is the primary function of the pulmonary circulation?

To pump deoxygenated blood from the heart to the lungs (D) Signup and view all the answers

Which of the following veins receives blood from the right bronchial veins?

Azygos vein (B) Signup and view all the answers

What is the characteristic of the pulmonary artery in terms of pressure?

Lower pressure than that in the aorta (A) Signup and view all the answers

What is the direction of the right pulmonary artery?

Horizontally towards the hilum of the right lung (B) Signup and view all the answers

What is the origin of the pulmonary trunk?

Right ventricle of the heart (C) Signup and view all the answers

What is the path of the pulmonary trunk after it arises from the right ventricle?

It passes to the left side of the ascending aorta for about 5cm before bifurcating (D) Signup and view all the answers

What is the main characteristic of the left pulmonary artery?

It is shorter and narrower than the right pulmonary artery (A) Signup and view all the answers

What is the primary function of the pulmonary veins?

To carry oxygenated blood from the lungs to the heart (A) Signup and view all the answers

What is the location of the bronchomediastinal lymph nodes?

In the neck, alongside the trachea and esophagus (D) Signup and view all the answers

What is the primary function of the lobar arteries?

To carry blood to each lobe of a lung (A) Signup and view all the answers

Where do the bronchomediastinal lymph nodes drain into?

The thoracic duct on the left side (C) Signup and view all the answers

What is the characteristic of lymphatic vessels in the lung?

They are absent on the walls of alveoli (A) Signup and view all the answers

What is the primary function of the parasympathetic fibers in the pulmonary plexus?

Bronchoconstriction and secretomotor (B) Signup and view all the answers

During inspiration, which muscle is responsible for increasing the vertical thoracic diameter?

Diaphragmatic muscle (A) Signup and view all the answers

What is the primary mechanism of expiration in the respiratory cycle?

Recoil of the respiratory muscles (A) Signup and view all the answers

Which nerve provides the parasympathetic fibers to the pulmonary plexus?

Vagus nerve (B) Signup and view all the answers

What is the proportion of air entering the lungs due to the contraction of the intercostal muscles?

25% (D) Signup and view all the answers

What is the source of the sympathetic fibers in the pulmonary plexus?

Sympathetic trunk (D) Signup and view all the answers