Respiratory Physiology I

Question 1

cannot be measured by spirometry

Answer 1

residual volume
FRC
TLC

Question 2

anatomic dead space

Answer 2

volume of air in the conducting airways

around 150mL

Question 3

physiologic dead space

Answer 3

volume of lungs not participating in gas exchange

-may be larger than anatomic dead space in V-Q mismatch lung disease

Question 4

alveolar dead space

Answer 4

air in alveoli not participating in gas exchange

Question 5

alveolar ventilation

Answer 5

Va = (Vt-Vd) x f

Vt = tidal volume
Vd = dead space
f = resp rate

Question 6

minute volume

Answer 6

tidal volume x breaths/min

Question 7

FRC

Answer 7

ERV + RV

Question 8

dead space = ?**

Answer 8

Vt x (PaCO2 - PeCO2) / PaCO2

arterial blood CO2
expired CO2

Question 9

inspiratory capacity

Answer 9

sum of tidal volume and IRV

Question 10

external intercostals

Answer 10

inspiration

Question 11

internal intercostals

Answer 11

exhalation

Question 12

inspiration

Answer 12

diaphragm down

-abdomen out (passive)

Question 13

expiration

Answer 13

diaphragm up (passive)
-abdomen in

Question 14

scalenes and sternocleidomastoids

Answer 14

forced inspiration

Question 15

forced expiration

Answer 15

recruits internal intercostals

Question 16

transpulmonary pressure

Answer 16

alveolar P - intrapleural P

equal and opposite to the lung elastic recoil pressure

positive - force holding alveoli open

Question 17

alveolar P

Answer 17

inspiration - negative

expiration - positive

Question 18

end inspiration

Answer 18

more negative intrapleural pressure

Question 19

pneumothorax

Answer 19

transpulmonary P is zero - wants to collapse

Question 20

lung compliance

Answer 20

change in volume / change in pressure

Question 21

elastic recoil of lung

Answer 21

elastin and collagen fibers

Question 22

laplace law

Answer 22

P = 2T/r

smaller radius - increased collapsing force on alveoli

Question 23

surfactant

Answer 23

• lowers surface tension
• increases alveolar stability
• keeps alveoli dry

Question 24

all lung volumes

Answer 24

positive pressure

-wants to collapse

Question 25

chest wall

Answer 25

wants to expand below 70% of total lung capacity

Question 26

slope of pressure volume curve

Answer 26

compliance**

Question 27

emphysema

Answer 27

obstructive

-increased compliance

Question 28

fibrosis

Answer 28

restrictive

-decreased compliance

Question 29

barrel chested

Answer 29

problem with exhalation

-breath at higher than normal lung volumes

Question 30

highest resistance

Answer 30

5th to 7th generation of bronchioles

distal airways - have low resistance

Question 31

bronchoconstrictors

Answer 31

PS - ACh
histamine
cig somke

Question 32

bronchodilators

Answer 32

S - NE beta adrenergic

beta 2 agonists

increased PCO2

Question 33

increased PCO2 in bronchioles

Answer 33

bronchodilation

Question 34

increased lung volume

Answer 34

decreased resistance

Question 35

pt with obstructive disease

Answer 35

breathe at higher lung volume to decrease airway resistance

Question 36

dynamic airways compression

Answer 36

forced expiration
-intrapleural pressure becomes positive

alveoli is very positive - but drops to 0 when reaches mouth

-at some point - this pressure is less than the intrapleural - causing the collapse of airways

healthy individuals - this occurs proximal airways - that are strengthened by cartilage

Question 37

FEV1/FVC

Answer 37

normal - 0.8

Question 38

obstructive diseases

Answer 38

problems with expiration

FEV1/FVC - decreased ratio

breathe at higher volumes

incrased FRC and TLC and RV

Question 39

restrictive disease

Answer 39

problems with inspiration

FEV1/FVC - increased ration

decreased FRC and TLC