pulmonary

Question 1

air-blood barrier

Answer 1

alveolar epithelium
capillary epithelium
basement membrane

very thin for easy diffusion

Question 2

ventilation definition/equation

Answer 2

Transport of gas from the atmosphere to the alveolar surface

minute ventilation (ml/min) = respiratory rate (breaths/min) x tidal volume (ml/breath)

Question 3

anatomic dead space

Answer 3

volume of conducting airways

~30% of tidal volume

Question 4

physiologic dead space

Answer 4

volume of alveoli that are ventilated but are not perfused with blood

low in healthy lungs. May be high in lung diseases

Question 5

collapsing tendency of lungs comes from

Answer 5

1/3 from elastic fibers in lung CT

2/3 from alveolar surface tension

Question 6

pressure is function of:

Answer 6

1) surface tension of the fluid
2) radius of the sphere

Small alveoli need more pressure to keep it open

Question 7

surfactant

Answer 7

Lowers surface tension by disrupting water-water interactions.

Secreted by type II alveolar cells

Detergent: dipalmitoyl phosphatidylcholine

Question 8

common problem with premature infant lungs

Answer 8

Lack surfactant –> cyanotic

Tx: inhaler with surfactant

Question 9

compliance of lung

Answer 9

Refers to change in volume as transmural pressure is changed

Question 10

[high or low] compliance at low lung volumes?

Answer 10

Low compliance at low lung volumes bc of high alveolar surface tension

Question 11

lung compliance in inflation vs deflation

Answer 11

Different slopes.

A greater pressure is needed to open a previously closed airway than to keep an open airway from closing.

Question 12

2 mechanisms to inflate the lungs

Answer 12

1) positive pressure: blowing up from pressure applied to trachea
2) applying negative pressure to the outside surface to suck it against the inner chest wall [* normal mechanism*]

Question 13

transpulmonary pressure

Answer 13

P(tp) = P(alv) - P(ip)

Keeps the lungs expanded in thoracic cavity.

Question 14

accessory muscles of inspiration

Answer 14

sternocleidomastoid
scalenes
pectoralis minor
serratus anterior

Question 15

accessory muscles of exhalation

Answer 15

internal intercostals
transversus thoracis
external oblique
rectus abdominus
internal oblique

Question 16

How does the thoracic cage change during inhalation?

Answer 16

Ribcage moves up/out (increases diameter of thoracic cage).
Diaphragm moves down (increases height of thoracic cage).
Lung expands (due to the expansion of the thoracic cage) --> decreased pressure in lungs --> air flows in

Question 17

How does the thoracic cage change during exhalation?

Answer 17

Ribcage moves down/in (decreases diameter of thoracic cage).
Diaphragm moves up (decreases height of thoracic cage).
Lung shrinks (due to the decreased volume of thoracic cage) --> increased pressure in lungs --> air flows out

Question 18

effect of airway resistance on ventilation

Answer 18

Smaller radius = larger resistance = decreased ventilation

A change in radius changes the resistance by a factor of 4

Question 19

Functional Residual Capacity (FRC)

Answer 19

amount of air left in lungs after normal expiration

Question 20

how to determine FRC

Answer 20

Helium dilution method

Question 21

residual volume (RV)

Answer 21

amount of air left in lungs after maximum expiration

Question 22

total lung capacity (TLC)

Answer 22

Total air possible in lung.

Max inspired, including residual volume.

Question 23

vital capacity (VC)

Answer 23

maximum inspired + expired

Question 24

tidal volume (VT)

Answer 24

normal, resting breath

Question 25

pulmonary arteries have ______ diameter and ________ smooth muscle than systemic arteries

Answer 25

Pulmonary arteries have larger diameter and less smooth muscle than systemic arteries

Question 26

An increase in pulmonary pressure results in [increase/decrease?] in resistance and [increase/decrease?] in blood flow

Answer 26

An increase in pulmonary pressure results in a decrease in resistance and and increase in blood flow.

Because: (1) previously collapsed vessels open up. (2) individual capillary segments increase their radii

Question 27

How does alveolar size affect alveolar blood vessels?

Answer 27

Expanded alveolar sacs compress alveolar vessels, increasing the resistance

Extra-alveolar vessels are pulled open by expansion of attached parenchymal tissue to decrease resistance.

Question 28

hypoxic vasoconstriction

Answer 28

pulmonary vessels constrict in response to local hypoxia to divert flow away from poorly ventilated alveoli

Question 29

T/F: pulmonary flow is pulsatile

Answer 29

True.

Pulmonary arteries do not damped the pulse generate by the R heart