Respiratory Physiology Part 2

Question 1

muscles of breathing

Answer 1

diaphragm
abdominals
internal intercostals

Question 2

diaphragm effect on breathing

Answer 2

when diaphragm contracts the abdominal contents are pushed down and ribs are lifted upward and outward

increases intrathoracic volume

Question 3

diaphragm increase intrathoracic volume which in turn causes ___

Answer 3

decreases intrathoracic pressure and initiates flow of air into lungs

Question 4

abdominals on breathing

Answer 4

compress abdominal cavity and push diaphragm up

Question 5

internal intercostals on breathing

Answer 5

pulls rib downward and inward

Question 6

function of expiratory muscles during exercise or disease

Answer 6

during an increase in airway resistance these muscles aid in the expiratory process

Question 7

compliance

Answer 7

• distensibility of the system
• how volume changes as a result of pressure change
• inversely correlated with elastance

Question 8

measuring lung compliance

Answer 8

requires simultaneous measurement of lung pressure and volume

Question 9

transmural pressure

Answer 9

pressure across a structure

Question 10

pressures equal to atmospheric pressure

Answer 10

zero

Question 11

pressure higher than atmospheric pressure

Answer 11

positive

Question 12

pressures lower that atmospheric pressure

Answer 12

negative

Question 13

Hysteresis

Answer 13

term used to describe the difference between inspiratory and expiratory compliance. Lung volume at any given pressure during inhalation is less than the lung volume at any given pressure during exhalation. Hysteresis is present in both static and dynamic lung compliance curves.

Question 14

why are inspiration and expiration curves different?

Answer 14

hysteresis

the intermolecular forces between liquid molecules lining the lung are much stronger than the forces between liquid and air molecules

Question 15

pneumothorax

Answer 15

sharp object punctures the intrapleural space

intrapleural pressure = atmospheric pressure

Question 16

2 consequences of pneumothorax

Answer 16

lung collapse

chest wall expands

Question 17

Volume is FRC

Answer 17

lungs wants to collapse

chest wall wants to expand

The combined lung and chest wall system NEITHER has a tendency to collapse NOR to expand

Question 18

Volume is less than FRC

Answer 18

forced expiration

• there is less volume in the lungs and the collapsing force of the lungs is smaller
• expanding force on chest wall is greater

combined system “wants to expand”

Question 19

Volume is greater than FRC

Answer 19

subject inspires

• more volume in the lungs / collapsing force is greater
• expanding force in chest wall is smaller

combined lung and chest wants to collapse

Question 20

diseases of lung compliance

Answer 20

emphysema

fibrosis

Question 21

Emphysema

Answer 21

increase lung compliance

COPD - loss of elastic fibers

Question 22

Fibrosis

Answer 22

decreased lung compliance

restrictive disease

Question 23

Emphysema effect on Volume is FRC

Answer 23

tendency for lungs to collapse is less than the tendency for the chest wall to expand

Question 24

How to balance out emphysema effect on Volume is FRC

Answer 24

volume must be added to increase their collapsing force

needs higher FRC

Question 25

Fibrosis effect on Volume is FRC

Answer 25

tendency of the lungs to collapse is greater than the tendency of the chest wall to expand

Question 26

How to balance out fibrosis effect on Volume is FRC

Answer 26

the lung and chest wall seak lower FRC

Question 27

Law of Laplace

Answer 27

pressure generated by surface tension in a sphere

Question 28

large aveolous = large radiss

Answer 28

low collapsing pressure

Question 29

small alveolus = small radius

Answer 29

high collapsing pressure

Question 30

surfactant

Answer 30

phospholipids that line alveoli and reduce surface tension = reduce collapsing pressure of small alveoli

increases lung compliance

Question 31

w/o surfactant effects

Answer 31

Law of Laplace predicts the small alveolus will collapse (atelectasis)

decreases lung compliance

Question 32

airflow is proportional to

Answer 32

pressure difference

Question 33

air flow is inversely proportional to

Answer 33

resistance of the airways

Question 34

Poiseuille’s Law on resistance and radius of airflow

Answer 34

if radius decreases, the resistances increases (16-fold)

when resistances increases, airflow is decreased

Question 35

medium sized bronchioles

Answer 35

site of the highest airway resistance

Question 36

bronchiole smooth muscle is innervated by ____ in parasympathetic and sympathetic

Answer 36

parasympathetic cholinergic nerve fibers

sympathetic adrenergic nerve fibers

Question 37

Autonomic effects on airway resistance

Answer 37

1. Parasympathetic
2. Sympathetic
3. Lung Volume
4. Viscosity of inspired air

Question 38

parasympathetic stimulation effect on airway resistance

Answer 38

constriction
decreases airway diameter
increase resistance

Question 39

sympathetic stimulation effect on airway resistance

Answer 39

vasodilation via Beta-2

increases airway
decreases resistance

(epinephrine and albuterol)

Question 40

lung volume effect on airway resistance

Answer 40

changes in lung volume alter airway resistance b/c the surrounding lung tissue exerts radial traction on airways

Question 41

High lung volume effect on airway resistance

Answer 41

greater traction
decrease airway resistance

people with asthma breathe at higher lung volumes

Question 42

low lung volume effect on airway resistance

Answer 42

less traction

increases airway resistance

Question 43

viscosity of inspired air effect on airway resistance

Answer 43

increase in gas viscosity = increase in resistance

decrease in viscosity = decrease in resistance