Lung Volumes and Ventilation

Question 1

What 3 processes have to happen in order to move O2 out of the lungs?

Answer 1

Ventilation, Diffusion, Blood flow

Question 2

What is Vd in the lungs?

Answer 2

This is the dead space where there is no gas exchange. Also called conducting zone

Question 3

What is tidal volume?

Answer 3

This is air that is brought in from inspiration

Question 4

In some species, the alveolar ventilation is equal to what?

Answer 4

Pulmonary blood flow

Question 5

What is the RBC transit time at rest?

Answer 5

0.84s

Question 6

What is the RBC transit time during exercise?

Answer 6

0.28s

Question 7

Why does RBC transit time decrease so much?

Answer 7

Your cardiac output increases significantly whil the capillary blood volume does not rise enough to make a difference

Question 8

What is the functional residual capacity of the lungs?

Answer 8

Volume in the lungs with no muscular forces

Question 9

What is Total Lung Capacity (TLC)?

Answer 9

Maximal inhalation

Question 10

What is residual volume (RV)?

Answer 10

Amount of air after maximum exhalation. Never able to reach zero

Question 11

Why do you not want the lungs to have no air in them?

Answer 11

This causes alveolar collapse and makes it hard to reopen in order for inspiration

Question 12

Why does rapid shallow breathing not increase the volume of air in the alveoli?

Answer 12

It wastes to much of the air in the dead space because air is not going all the way down in the lungs to the major respiratory zones

Question 13

Why is ventilation greater at the base of the lungs?

Answer 13

Gravity

Question 14

How do you measure RBC transit time?

Answer 14

Pul. cap. blood volume / Q

Question 15

How do you calculate tidal volume?

Answer 15

Vt= Vd + Va

Question 16

How do you calculate the expired ventilation?

Answer 16

Vt x f= (Vd x f) + (Va x f)

Question 17

What does the ratio between Vd/ Vt tell us?

Answer 17

Help us to determine how much of the air is being ventilated to the alveoli. Vt increases with exercise so it lowers the ratio

Question 18

What is anatomical dead space

Answer 18

Non gas exchanging volume from the conducting zone

Question 19

What is physiological dead space?

Answer 19

Mismatch of ventilation and blood flow

Question 20

What is Bohrs equation?

Answer 20

Vd/Vt= (PaCO2 - PeCO2)/PaCO2

Question 21

What does Bohr’s equation show us?

Answer 21

Shows that if you increase Vd/ Vt you are going to decrease the pressure of expired air. This is because you are not breathing deep enough and you increase the amount of dead space you have.

Question 22

How do you calculate alveolar ventilation and why is it important?

Answer 22

Va= (VCO2/PaCO2) x k. Shows that the alveolar ventilation is going to increase with the VCO2 to maintain a pH near 7.4