CTB3

Question 1

What is pulmonary ventilation?

Answer 1

The movement of air into and out of the lungs.

Question 2

What is alveolar ventilation?

Answer 2

The volume of air reaching the alveoli for gas exchange per minute.

Question 3

How is alveolar ventilation calculated?

Answer 3

Alveolar ventilation = (Tidal Volume - Dead Space) × Respiratory Rate.

Question 4

What is tidal volume (VT)?

Answer 4

The amount of air inhaled or exhaled during a normal breath.

Question 5

What is dead space?

Answer 5

Air in the respiratory tract that does not participate in gas exchange.

Question 6

What are the two types of dead space?

Answer 6

Anatomical dead space (conducting airways) and alveolar dead space (non-perfused alveoli).

Question 7

What is physiological dead space?

Answer 7

The sum of anatomical and alveolar dead space.

Question 8

How is oxygen transported in the blood?

Answer 8

Primarily bound to haemoglobin and a small amount dissolved in plasma.

Question 9

How is carbon dioxide transported in the blood?

Answer 9

As bicarbonate ions (majority), bound to haemoglobin, or dissolved in plasma.

Question 10

What is the oxygen-haemoglobin dissociation curve?

Answer 10

A graph showing the relationship between haemoglobin saturation and oxygen partial pressure.

Question 11

What is the Bohr effect?

Answer 11

The reduction in haemoglobin’s oxygen-binding affinity due to increased CO2 or H+ concentration.

Question 12

How does exercise affect the dissociation curve?

Answer 12

The curve shifts right, facilitating oxygen unloading in tissues.

Question 13

What is the role of the respiratory muscles during inspiration?

Answer 13

The diaphragm and external intercostal muscles contract, expanding the thoracic cavity.

Question 14

What drives expiration at rest?

Answer 14

Passive recoil of the lungs and chest wall.

Question 15

How does forced expiration differ from passive expiration?

Answer 15

It involves active contraction of abdominal and internal intercostal muscles.

Question 16

What is compliance in the lungs?

Answer 16

The ability of the lungs to expand in response to pressure changes.

Question 17

How does reduced compliance affect breathing?

Answer 17

It makes lung expansion more difficult, as seen in fibrosis.

Question 18

What is resistance in the airways?

Answer 18

The opposition to airflow caused by airway diameter and turbulence.

Question 19

What factors influence airway resistance?

Answer 19

Airway diameter, smooth muscle tone, and mucus presence.

Question 20

How does asthma affect airway resistance?

Answer 20

It increases resistance due to bronchoconstriction and mucus production.

Question 21

What is the importance of surfactant?

Answer 21

It reduces alveolar surface tension, preventing alveolar collapse.

Question 22

How is surfactant produced?

Answer 22

By type II alveolar cells.

Question 23

What is the role of haemoglobin in oxygen transport?

Answer 23

Haemoglobin binds oxygen in the lungs and releases it in tissues.

Question 24

What is Fick’s law of diffusion?

Answer 24

Gas diffusion rate is proportional to surface area, concentration gradient, and inversely proportional to membrane thickness.

Question 25

How does emphysema affect gas exchange?

Answer 25

It reduces alveolar surface area, impairing diffusion.

Question 26

How does pulmonary fibrosis affect gas exchange?

Answer 26

It thickens the alveolar membrane, reducing diffusion efficiency.

Question 27

What is ventilation-perfusion matching?

Answer 27

The coordination of airflow (ventilation) and blood flow (perfusion) in the lungs for optimal gas exchange.

Question 28

What is the significance of the V/Q ratio?

Answer 28

The ventilation-perfusion ratio determines the efficiency of gas exchange.

Question 29

What causes a low V/Q ratio?

Answer 29

Poor ventilation relative to perfusion, as seen in asthma or pneumonia.

Question 30

What causes a high V/Q ratio?

Answer 30

Reduced perfusion relative to ventilation, as seen in pulmonary embolism.

Question 31

What is hypoxic pulmonary vasoconstriction?

Answer 31

Constriction of pulmonary vessels in poorly ventilated areas to redirect blood to better-ventilated regions.

Question 32

How is breathing rate regulated?

Answer 32

By the respiratory centres in the medulla oblongata and pons.

Question 33

What are central chemoreceptors?

Answer 33

Receptors in the medulla that detect changes in CO2 and pH levels in cerebrospinal fluid.

Question 34

What are peripheral chemoreceptors?

Answer 34

Receptors in the carotid and aortic bodies that detect changes in O2, CO2, and pH in arterial blood.

Question 35

How does hypercapnia affect ventilation?

Answer 35

Increased CO2 stimulates central chemoreceptors, increasing ventilation rate.

Question 36

What is the role of the diaphragm in ventilation?

Answer 36

Its contraction increases thoracic volume, reducing intrapulmonary pressure to draw air in.

Question 37

How does altitude affect oxygen transport?

Answer 37

Low partial pressure of oxygen reduces arterial oxygen saturation.

Question 38

What is hypoxaemia?

Answer 38

Low oxygen levels in arterial blood.

Question 39

How does chronic obstructive pulmonary disease (COPD) affect ventilation?

Answer 39

COPD increases airway resistance and reduces alveolar ventilation.

Question 40

What is hyperventilation?

Answer 40

Excessive ventilation leading to decreased arterial CO2 (hypocapnia).

Question 41

What is hypoventilation?

Answer 41

Reduced ventilation causing elevated arterial CO2 (hypercapnia).

Question 42

How does haemoglobin saturation change with exercise?

Answer 42

Increased demand causes more oxygen to be released to tissues (rightward curve shift).

Question 43

How is carbonic acid formed in blood?

Answer 43

CO2 reacts with water, catalysed by carbonic anhydrase.

Question 44

How is carbonic acid buffered?

Answer 44

It dissociates into bicarbonate and hydrogen ions, maintaining blood pH.

Question 45

What is respiratory acidosis?

Answer 45

A condition where CO2 retention lowers blood pH.

Question 46

What is respiratory alkalosis?

Answer 46

A condition where excessive CO2 loss raises blood pH.

Question 47

How does the body compensate for metabolic acidosis?

Answer 47

By increasing ventilation to expel CO2.

Question 48

What is the significance of the partial pressure gradient for oxygen?

Answer 48

It drives oxygen diffusion from alveoli to blood.

Question 49

What is the significance of the partial pressure gradient for CO2?

Answer 49

It drives CO2 diffusion from blood to alveoli.

Question 50

How does pulmonary oedema affect gas exchange?

Answer 50

Fluid accumulation in alveoli reduces gas diffusion efficiency.