Lec 25

Question 1

Surfactant secreted by

Answer 1

alveolar type II cels

Question 2

surfactant function

Answer 2

Lines the inside of the alveoli
2- decrease surface tension
2.1- decrease inard pressure
3- prevent alveoli from collapsing
4- alveoli easier to expand
5- equalizer– smaller bubbles have more force to collapse – surfactant equalize tendency of different size fo molecules to collapse – pump more surfactant to smaller bubble

Question 3

decrease surface tension will

Answer 3

decrease the pressure make alveoli easier to expand

Question 4

Law of Laplace

Answer 4

P=2T/r (p=pressure,T=tension,r=radius)

Question 5

intrapleural pressure P(ip)

Answer 5

always negative
-4mmHg relatiove to atmosphere

Question 6

intra-alveolar pressure P(alv)

Answer 6

Normally 0 mmHg relative to atmosphere

Question 7

transpulmonary pressure

Answer 7

P(alv)-P(ip)

Question 8

normal transpulmonary pressure

Answer 8

0 - (-4)=4

Question 9

Pneumothorax

Answer 9

if air enters pleural sac
bond holding lung to chest wall is broken and lung collapse

Question 10

changes during quiet breathing

Answer 10

1- chest expansion lower p(ip)
2- transpulmonary pressure increase
3- pressure forces lung toward chest wall increase
4- lungs expand and p(alv) decrease
5- air flows into lung (p alv=p atm)

Question 11

max vol of air during normal inspiration

Answer 11

500 ml

Question 12

2 important property lung for normal function

Answer 12

1- high compliance (breath in)
2- elastic recoil (breath out)

Question 13

if problem with elastic recoil

Answer 13

broblem with breath out
should force exhale

Question 14

Compliance

Answer 14

ability of lung to stretch
change in vol. for given change in pressure

Question 15

decrease compliance diseases

Answer 15

restrictive pulmonary diseases
ex: fibrosis

Question 16

elastance

Answer 16

ability to spring back after being stretched
due to presence elastin fibers

Question 17

decrease in elastin content disease

Answer 17

emphysema

Question 18

what happens when inspiratory muscle contract

Answer 18

1- lung vol increase
2- pressure inside lung decrease
3- air is sucked in

Question 19

what happens when inspiratory muscle relax

Answer 19

1- lung vo. decrease
2- pressure inside lung increase
3- air is blown out

Question 20

mechanical changes during inspiration

Answer 20

1- diaphragm contract and flatten
2- muscles of inspiration contract
3- thoracic and lung vol. increase
4- p atm > p alv
5- air flow in

Question 21

mechanical changes during expiration

Answer 21

1- diaphragm relax and move up
2- muscles inspiration relax
3- thoracic and lung vol. decrease
4- p alv > p atm
5- air flow out

Question 22

what measures pulmonary function

Answer 22

spirometry

Question 23

tidal volume

Answer 23

normal inhale/exhale (500)

Question 24

residual volume

Answer 24

minimum left (1200)

Question 25

inspiratory reserve volume

Answer 25

inhale everything (3000)

Question 26

expiratory reserve volume

Answer 26

exhale every thing (1100)

Question 27

total lung capacity

Answer 27

5800 ml

Question 28

inspiratory capacity

Answer 28

IRV + TV (3500)

Question 29

vital capacity

Answer 29

total - residual (4600)

Question 30

functional residual capacity

Answer 30

normally left out in lung and airways (2300)

Question 31

pulmonary ventilation formula

Answer 31

ventilation rate * tidal volume

Question 32

normal total pulmonary ventilation per minute

Answer 32

6L/min
conducting airways is deadspace having air to not collapse

Question 33

alveolar ventilation formula

Answer 33

ventilation rate * (TV-dead space vol.)

Question 34

normal alveolar ventilation

Answer 34

12* (500-150)=4.2 L/min