Respiration Mechanics

Question 1

what are the two meanings of respiration

Answer 1

tissue respiration - cellular level, aerobic respiration in cells
breathing - system level - gas exchange and processes

Question 2

respiration mechanics

Answer 2

process by which air enters the lungs and mechancial properties of lungs and chest wall

Question 3

what does lung disease usually cause defects in

Answer 3

respiration mechanics

Question 4

partial pressure

Answer 4

pressure of a gas in a gas mixture if that gas was alone in the same environment

Question 5

at rest, what is the partial pressure of O2 and CO2

Answer 5

PO2 = 100 +/- 2 mmHg 
PCO2 = 40 +/- 2 mmHg

Question 6

at rest, what volume of O2 and CO2 is exchanged

Answer 6

O2 - 250ml

CO2 - 200ml

Question 7

during strenuous exercise, what volume of O2 and CO2 is exchanged

Answer 7

O2 - 2000ml

CO2 - 2500ml

Question 8

functions of the upper airways

Answer 8

• humidify - saturate the dry air with water vapour - nasal cavity
• warms air - nasal cavities
• filter air - upper airways lined with pseudostratified ciliated columnar epithelium. Mucuous traps dirt from air and cilia beat this to stomach or nose to be expelled

Question 9

what type of epithelium are the upper airways lined with

Answer 9

pseudostratified ciliated columnar epithelium

Question 10

quiet breathing

Answer 10

occurs at rest, requires no cognitive thought

inspiration is an active process, expiration is a passive

Question 11

strenuous breathing

Answer 11

occurs during strenuous exercise/ respiratory failure etc

both inspiration and expiration are active processes

Question 12

describe the breathing process of inspiration

Answer 12

1 - diaphragm and external intercostals contract increasing the space of the thoracic cavity and decreasing the pressure
2 - pleural cavity pressure also decreases to to less than the pulmonary cavity pressure so lungs expand
3 - this expansion causes a decrease in pressure causing air to move from atmosphere to the lungs

Question 13

describe the breathing process of expiration

Answer 13

diaphragm and intercostal muscles relax therefore abdominal cavity pushes against the thoracic cavity increasing pleural and pulmonary pressures which therefore causes air to leave the lungs for the atmosphere

Question 14

why is intrapleural pressure always negative

Answer 14

due to the suction effect of the lungs (pulmonary cavity) pushing in and the chest wall pushing out

Question 15

functional residual capacity

Answer 15

volume of air left in the lungs after expiration during quiet breathing

Question 16

describe the alveolar and pleural pressure changes that occur during ventilation

Answer 16

1 - at the beginning of inspiration alveolar pressure = 0 as there is no flow
2 - muscles contract and pleural pressure becomes more negative and alveolar pressure drops below 0
3 - flow stops when alveolar pressure and atmospheric pressures are equal