Resp 2

Question 1

What are the main functions of the respiratory system?

Answer 1

Gas exchange, acid-base balance, protection, communication

Question 2

How does the respiratory system contribute to energy production?

Answer 2

Delivers O2 for ATP production and removes CO2 waste

Question 3

What is the difference between external and internal respiration?

Answer 3

External: gas exchange in lungs; Internal: cellular respiration

Question 4

What is the main site of gas exchange?

Answer 4

Alveoli

Question 5

What maintains airway patency in the conducting zone?

Answer 5

C-shaped cartilage rings

Question 6

What are Type I and Type II alveolar cells?

Answer 6

Type I: gas exchange; Type II: surfactant secretion

Question 7

What is anatomical dead space?

Answer 7

Air in the conducting zone that does not participate in gas exchange

Question 8

How does airway resistance vary?

Answer 8

It is inversely related to airway radius and airflow becomes more laminar down the tract

Question 9

What are the primary lung volumes?

Answer 9

TV, IRV, ERV, RV

Question 10

What are lung capacities?

Answer 10

VC, TLC, IC, FRC (combinations of primary volumes)

Question 11

What is Boyle’s Law?

Answer 11

Pressure inversely proportional to volume

Question 12

What is transpulmonary pressure?

Answer 12

Difference between alveolar and intrapleural pressure (P_T = P_A - P_ip)

Question 13

How do the pleural membranes aid lung expansion?

Answer 13

They stick the lungs to the chest wall via cohesive pleural fluid

Question 14

What is the role of surfactant?

Answer 14

Reduces surface tension, prevents alveolar collapse, increases compliance

Question 15

What is lung compliance?

Answer 15

Change in lung volume for a given change in pressure; reflects distensibility

Question 16

What causes Infant Respiratory Distress Syndrome?

Answer 16

Lack of surfactant in premature babies

Question 17

What is pulmonary ventilation?

Answer 17

Total air moved into/out of lungs per minute

Question 18

What is alveolar ventilation?

Answer 18

Fresh air reaching alveoli per minute, available for gas exchange

Question 19

What is dead space volume?

Answer 19

Volume of air not involved in gas exchange (~150 mL)

Question 20

What affects alveolar ventilation more: rate or depth?

Answer 20

Depth of breathing, due to impact of dead space

Question 21

What happens to PO2 and PCO2 during hyperventilation?

Answer 21

PO2 ↑ to ~120 mmHg, PCO2 ↓ to ~20 mmHg

Question 22

What happens to PO2 and PCO2 during hypoventilation?

Answer 22

PO2 ↓ to ~30 mmHg, PCO2 ↑ to ~100 mmHg

Question 23

What is the partial pressure of oxygen in alveoli under normal conditions?

Answer 23

100 mmHg

Question 24

What law describes gas diffusion in lungs?

Answer 24

Dalton’s Law and simple diffusion principles

Question 25

What factors influence gas diffusion across alveoli?

Answer 25

Partial pressure gradient, solubility, surface area, membrane thickness

Question 26

What is the difference between pulmonary and bronchial circulation?

Answer 26

Pulmonary: gas exchange; Bronchial: tissue nourishment

Question 27

What is the ventilation-perfusion (V/Q) ratio?

Answer 27

The ratio of air reaching the alveoli to blood reaching the alveoli

Question 28

How does gravity affect V/Q in the lungs?

Answer 28

Base: perfusion > ventilation (V/Q < 1); Apex: ventilation > perfusion (V/Q > 1)

Question 29

What is a 'shunt' in lung physiology?

Answer 29

Perfusion of poorly ventilated alveoli

Question 30

What is alveolar dead space?

Answer 30

Ventilated alveoli with poor perfusion

Question 31

What is physiological dead space?

Answer 31

Anatomical dead space + alveolar dead space

Question 32

How is V/Q mismatch compensated?

Answer 32

By local vasoconstriction in hypoxic regions to redirect blood flow

Question 33

What are the two forms O2 is transported in blood?

Answer 33

Bound to haemoglobin (98%) and dissolved in plasma (2%)

Question 34

What determines haemoglobin saturation with O2?

Answer 34

Partial pressure of O2 (PaO2)

Question 35

What shifts the oxygen dissociation curve right?

Answer 35

↓pH, ↑PCO2, ↑temperature, ↑2,3-DPG (Bohr effect)

Question 36

How is most CO2 transported in the blood?

Answer 36

As bicarbonate (HCO3-) in plasma (~70%)

Question 37

What enzyme facilitates CO2 transport as bicarbonate?

Answer 37

Carbonic anhydrase

Question 38

Where are central chemoreceptors located and what do they detect?

Answer 38

In medulla; detect CSF pH changes due to CO2

Question 39

Where are peripheral chemoreceptors located and what do they detect?

Answer 39

Carotid and aortic bodies; detect arterial PO2, PCO2, and H+

Question 40

What is the main stimulus for ventilation under normal conditions?

Answer 40

Increased PaCO2 (hypercapnia)

Question 41

What is the effect of hypoventilation on acid-base balance?

Answer 41

Causes respiratory acidosis due to CO2 retention

Question 42

What is the effect of hyperventilation on acid-base balance?

Answer 42

Causes respiratory alkalosis due to CO2 loss

Question 43

Why can administering O2 to COPD patients be dangerous?

Answer 43

They may rely on hypoxic drive; O2 reduces their ventilatory drive

Question 44

How does the body respond to increased [H+]?

Answer 44

Stimulates ventilation via peripheral chemoreceptors

Question 45

What limits voluntary control of breathing?

Answer 45

Chemical signals like increased PaCO2 override voluntary control

Question 46

What is the respiratory response during strenuous exercise?

Answer 46

Ventilation exceeds metabolism; lactic acid increases [H+] triggering hyperventilation

Question 47

What is the primary role of the respiratory system in acid-base balance?

Answer 47

Regulates blood pH by altering CO2 levels