West Chp 1

Question 1

Function of the lung?

Answer 1

• Gas exchange
• Allow oxygen to move from the air into venous blood, CO2 to move out
• Also metabolizes some compounds, filters unwanted materials from the circulation, acts as reservoir for blood

Question 2

How do O2, CO2 move btw air and blood?

Answer 2

Simple diffusion –> area of high to low partial pressure

Question 3

Fick’s Law of Diffusion

Answer 3

Amount of gas that moves across a sheet directly proportional to area of the sheet but inversely proportional to the thickness

Question 4

Blood-gas barrier

Answer 4

Exceedingly thin, area btw 50-100m^2

Question 5

How able to have such large area for diffusion inside limited thoracic cavity?

Answer 5

Wrapping small vessels (capillaries) around an enormous number of small air sacs (alveoli)
Human lung = 500 million alveoli, each approx 1/3 mm in diameter
Lung generates large diffusion area by being divided into myriad of units

Question 6

How gas brought to gas-blood interface?

Answer 6

Airways, blood vessels

Question 7

Airway

Answer 7

Branching tubes that become narrower, shorter and more numerous as penetrate deeper into the lung

Question 8

Branching of airway

Answer 8

Trachea –> right, left main bronchi –> lobar bronchi –> segmental bronchi –> terminal bronchioles –> respiratory bronchioles –> alveolar ducts (lined with alveoli)

Question 9

Terminal bronchioles?

Answer 9

Smallest airways without alveoli