Control of Breathing

Question 1

What muscles are primarily involved in inspiration?

Answer 1

The diaphragm and external intercostal muscles contract during inspiration, increasing thoracic volume and reducing intrapulmonary pressure, allowing air to flow into the lungs.

Question 1

What are the two phases of respiration?

Answer 1

The two phases of respiration are inspiration (inhaling air into the lungs) and expiration (exhaling air out of the lungs).

Question 2

What role does the pleura play in respiration?

Answer 2

The pleura consists of two layers, visceral and parietal pleura, that form a lubricated surface allowing the lungs to expand and contract with minimal friction.

Question 2

How does expiration occur under normal conditions?

Answer 2

Expiration is usually a passive process caused by the relaxation of the diaphragm and external intercostal muscles, allowing the lungs to recoil and air to flow out.

Question 3

What happens when there is a V/Q mismatch?

Answer 3

A V/Q mismatch can result in areas of the lung receiving too much air and too little blood flow (dead space) or too little air and too much blood flow (shunt), impairing gas exchange.

Question 4

What is V/Q matching?

Answer 4

V/Q matching refers to the balance between ventilation (V) (air reaching the alveoli) and perfusion (Q) (blood flow to the alveoli), essential for optimal gas exchange.

Question 5

How is carbon dioxide transported in the blood?

Answer 5

Carbon dioxide is transported in three forms: dissolved in plasma (10%), bound to hemoglobin as carbaminohemoglobin (20%), and primarily as bicarbonate ions (HCO3-) (70%).

Question 6

What is the Bohr effect?

Answer 6

The Bohr effect describes how increased CO2 and acidity in tissues reduce hemoglobin’s affinity for oxygen, promoting oxygen release to tissues.

Question 7

How is oxygen primarily transported in the blood?

Answer 7

Oxygen is mainly transported in the blood bound to hemoglobin in red blood cells (~98.5%), with a small percentage dissolved in the plasma.

Question 8

What is the Haldane effect?

Answer 8

The Haldane effect refers to how deoxygenated blood can carry more carbon dioxide than oxygenated blood, facilitating CO2 transport back to the lungs.

Question 8

What are the surface markings of the lungs?

Answer 8

The apex of the lungs extends above the clavicles, while the base rests on the diaphragm. The anterior borders meet at the midline at the 2nd rib and extend laterally to the 6th rib at the midclavicular line.

Question 9

What is the location of the lung’s oblique fissure?

Answer 9

The oblique fissure runs from the T2 vertebra posteriorly to the 6th rib anteriorly, separating the upper and lower lobes of the lungs.

Question 10

What is pleurisy?

Answer 10

Pleurisy is inflammation of the pleura, often resulting in sharp chest pain that worsens with breathing due to friction between the inflamed pleural layers.

Question 10

What is the location of the horizontal fissure of the right lung?

Answer 10

The horizontal fissure is located at the level of the 4th rib, separating the upper and middle lobes of the right lung.

Question 11

What is a pneumothorax?

Answer 11

A pneumothorax is the presence of air in the pleural cavity, causing lung collapse due to the loss of negative pressure between the pleural layers.

Question 12

What is a pleural effusion?

Answer 12

A pleural effusion is the accumulation of excess fluid in the pleural space, leading to breathlessness and reduced lung expansion.

Question 13

How does pleural injury affect lung function?

Answer 13

Injury to the pleura, such as in a pneumothorax or pleural effusion, compromises the lung’s ability to expand properly, leading to impaired ventilation.

Question 14

How many lobes does the right lung have?

Answer 14

The right lung has three lobes: the upper, middle, and lower lobes.

Question 15

How many lobes does the left lung have?

Answer 15

The left lung has two lobes: the upper and lower lobes, and a cardiac notch for the heart.

Question 16

What are bronchopulmonary segments?

Answer 16

Bronchopulmonary segments are functionally independent units of the lung, each receiving air from its own segmental bronchus and blood from its own artery.

Question 16

What is the bronchial tree?

Answer 16

The bronchial tree is a branching system of airways that begins with the trachea, divides into the primary bronchi, then into secondary (lobar) bronchi, tertiary (segmental) bronchi, and finally into smaller bronchioles.

Question 17

How many bronchopulmonary segments are in each lung?

Answer 17

The right lung has 10 bronchopulmonary segments, while the left lung has 8-10 segments, depending on the source.

Question 17

What is the function of alveoli in the lungs?

Answer 17

Alveoli are small air sacs where gas exchange occurs between the air in the alveoli and the blood in the surrounding capillaries.

Question 18

What is the role of surfactant in the alveoli?

Answer 18

Surfactant, produced by type II alveolar cells, reduces surface tension within the alveoli, preventing their collapse during expiration.

Question 19

What is the significance of pulmonary capillaries in gas exchange?

Answer 19

Pulmonary capillaries surround alveoli, allowing for the diffusion of oxygen into the blood and the removal of carbon dioxide from the blood.

Question 20

What happens in the respiratory zone of the lungs?

Answer 20

The respiratory zone includes the respiratory bronchioles, alveolar ducts, and alveoli, where gas exchange takes place.

Question 21

What is the respiratory membrane?

Answer 21

The respiratory membrane is the thin barrier between the alveolar air and the blood in the capillaries, consisting of the alveolar epithelium, capillary endothelium, and their fused basement membranes.

Question 21

What structures are involved in the conducting zone of the lungs?

Answer 21

The conducting zone includes the trachea, bronchi, bronchioles, and terminal bronchioles, which serve to conduct, humidify, and warm the air.

Question 22

How does gas exchange occur in the lungs?

Answer 22

Gas exchange occurs via simple diffusion across the alveolar-capillary membrane, with oxygen moving from alveoli into the blood and carbon dioxide moving from blood into the alveoli.

Question 22

What is the function of the diaphragm in respiration?

Answer 22

The diaphragm is the primary muscle of respiration, contracting during inspiration to increase thoracic cavity volume and allowing the lungs to expand.