Respiratory Physiology - Gas Exchange

Question 1

What is the equation for airway resistance and what does it mean if the radius of the tube is increased or decreased

Answer 1

Resistance = 8nl/r(tt4)

Increasing the radius will decrease the resistance

Decreasing the radius will increase the resistance

Question 2

How much oxygen and co2 are exchanged. Every minute in the lungs

Answer 2

250 ml O2

200 ml C02

Question 3

What factors depend directly on the structure of the alveolus

Answer 3

The surface area available for diffusion and the distance (thickness of the alveolar barrier)

Question 4

At rest, there is how much blood in the pulmonary capillaries

Answer 4

70 ml

Question 5

What does the deposition of collagen do to gas exhcnage

Answer 5

Increases diffusion distance and decreases gas diffusion

Question 6

Is oxygen or cO2 more soluable in water

Answer 6

CO2 (20x as much)

Question 7

What is the pressure gradient of oxygen in the alveolar space and what does this mean

Answer 7

60 mmHg

Oxygen wants to be pushed into the RBC

Question 8

What is the pressure gradient of Co2 in the alveolar space and what does this mean

Answer 8

-5mmHg

CO2 wants to go into the alveolar space from the RBC

Question 9

How to calculate Diffusion capacity of O2 in the lungs

Answer 9

DLO2 = 1.23 x DLCO

Question 10

Why will people with a lung disease notice the first symptoms while working out

Answer 10

During exercise, the alveolar capillaries open more, which allows the lungs to accommodate increased blood flow from the heart. This is good and allows more RBC’s to pass through the lungs and be oxygenated quickly. However, in some one with lung disease, the capillaries do not open up as much, thus the lungs can not accommodate the increased flow of blood as well and they person become hypoxic faster.

Question 11

In a person with lung diseases, what is a result from the capillaries not opening enough

Answer 11

Oxygen retention, which will drive COPD and cause a reversal of the chemomonitors within the lungs and the patient will become oxygen driven

Question 12

What produces surfactant

Answer 12

Type II pneumocytes

Question 13

Why do alveoli collapse and what stops it

Answer 13

Alveoli of different sizes exist. Small alveoli have small radius but big pressure, and large alveoli have large radius with small pressure. This causes the small alveoli with large pressure to send air to the larger one and collapse into the bigger one. This will continue to happen without the presence of surfactant .

Question 14

What does surfactant do

Answer 14

Reduces tension in the smallest alveoli more than larger alveoli