Lecture 1: Respiration I

Question 1

FEV1

Answer 1

Forced Expiratory Volume in 1 second. How much air can be forced out in 1 second.

Question 2

Lateral traction in lungs

Answer 2

CT connect alveoli to surrounding airways (elastin, collagen, spongin) keeping alveoli open

Question 3

Transpulmonary pressure

Answer 3

Always > 0. Equal to P_alveolar - P_intrapleural. Prevents collapse at rest.

Question 4

Intrapleural pressure

Answer 4

At rest, P_ip < 0 which keeps the lungs open and the chest wall in. Counters natural elastic recoil.

Question 5

Functional Residual Capacity

Answer 5

Volume at end of passive expiration. Point at which lung and chest wall recoil forces are equal.

Question 6

Normal respiratory cycle

Answer 6

1. @ FRC P_alv = P_atm, P_ip < 0 so TPP > 0.
2. Muscle contraction lowers P_ip -> airways expand, lowering P_alv and sucking in air.
3. At end of inspiration P_alv = atm again.
4. Insp. muscles relax, compressing IP space and making P_alv > atm, pushing air out in expiration.

Question 7

Tidal volume

Answer 7

Relaxed breathing volume

Question 8

Inspiratory capacity

Answer 8

Volume of maximal inspiration

Question 9

Vital capacity

Answer 9

Functional lung volume; includes maximal inspiration and maximal expiration

Question 10

Residual volume

Answer 10

Volume left after maximal expiration

Question 11

Expiratory reserve volume

Answer 11

Additional volume that can be expired after passive expiration

Question 12

Inspiratory reserve volume

Answer 12

Additional volume that can be inspired after passive inspiration

Question 13

Total Lung Capacity

Answer 13

Full volume of lungs, including RV and VC

Question 14

Boyle’s Law

Answer 14

P1V1 = P2V2

Question 15

Fick’s Law for Diffusion of Gases

Answer 15

V_gas = DAS (P1 - P2 / Δx)

Question 16

Graham’s Law of Diffusion by MW

Answer 16

Diffusion rate is inversely proportional to molecular weight; D_x / D_y = sqrt(MW_y) / sqrt(MW_x)

Question 17

Factors affecting lung volume

Answer 17

1. Transpulmonary pressure (transmural pressure)
2. Lung compliance

Question 18

Equation for lung compliance

Answer 18

C = ΔV / ΔP_tp

Question 19

Minute ventilation Ve

Answer 19

Ve = tidal vol. x RR

Question 20

Dead space

Answer 20

Inspired volume that does not take part in gas exchange

Question 21

Anatomical dead space

Answer 21

Dead space due to air filling conducting airways aka sites that do not participate in gas exchange

Question 22

Physiological dead space

Answer 22

Anatomical + alveolar dead space

Question 23

Alveolar dead space

Answer 23

Air that enters unperfused alveoli and so do not participate in gas exchange; in a healthy individual, alveolar dead space = 0

Question 24

Alveolar ventilation Va

Answer 24

Va = (tidal vol. - dead space) x RR