Respiratory

Question 1

intrapleural pressure

Answer 1

the pressure within the pleural space relative to atmospheric pressure (-4 ~ -7)

Question 2

alveolar pressure

Answer 2

pressure within the alveoli relative to Patm(0 ~ 1)

Question 3

atmospheric pressure

Answer 3

760mmHg

Question 4

transpulmonary pressure

Answer 4

pressure difference between alveoli and pleural space. little man pushing the lungs open.

Question 5

inspiration and pressures

Answer 5

Pip: from -4 to -7 mmHg (more negative
Palv: at mid inspiration; 0 - 1 (gas exchange)
Ptp:

Question 6

expiration and pressures

Answer 6

Pip: from -7 to -4(less negative)
Palv; from 1 - 0
Ptp

Question 7

determinants of lung compliance

Answer 7

1. elastic elements(25% of bounce back)
2. surface tension(surfactant - 75% of bounce back

Question 8

determinants of airway resistance, and what other determinants impact the most important of these

Answer 8

1. viscosity of air(low)
2. length of airways(fixed)
3. diameter/radius(large, but variable)
   
   • affected by physical factors(lung expansion & relaxation), chemical factors(mucous blockage & bronchoconstriction by local inflammatory chemical mediators), neural factors(bronchoconstriction by parasympathetic signalling - through muscarinic ach receptors)

Question 9

factors of gas diffusion in liquid

Answer 9

1. diffusion properties of gas
2. alveolar wall thickness
3. alveolar surface area
4. partial pressure difference

Question 9

how much of each gas in the air(%)

Answer 9

21% oxygen
79% nitrogen
0.04% CO2

Question 10

ventilation-perfusion matching

Answer 10

better ventilated parts of the lungs become better perfused.

Question 11

O2 transport methods and amounts

Answer 11

1. dissolved in plasma –> 3ml (1.5%)
2. bound to haemoblobin –> 197ml (98.5%)

Question 12

CO2 transport methods and amounts

Answer 12

1. dissolved in plasma –> (~10%)
2. bound to haemoglobin –> (~60%)
3. as bicarbonate(HCO3-) –> (~60%)

Question 13

haldan effect

Question 14

bohr effect

Question 15

involuntary breathing control

Answer 15

controlled in the medulla oblongata by
- inspiratory centre –> always active
- expiratory centre –> usually inactive
receives input from mechanoreceptors and chemoreceptors

Question 16

voluntary breathing control

Answer 16

cerebral cortex

Question 17

protective reflexes:

Answer 17

Sneeze:
- nasal mucosa mechanoreceptor irritation
- several inspiration superimposed, followed by a powerful expiration

Cough:
- larynx mechanoreceptor irritation
- long, slow inspiration, followed by a powerful expiration