Physiology 2 - Respiratory mechanisms

Question 1

2 major inspiratory muscles

Answer 1

1) diaphragm

2) external intercostal muscles

Question 2

3 accessory muscles of inspiration

Answer 2

1) sternacleidomastoid
2) scalenus
3) pectoral

Question 3

2 muscles of active expiration

Answer 3

1) abdominal muscles

2) internal intercostal muscles

Question 4

tidal volume

Answer 4

volume of air entering of leaving lungs during a single breath

Question 5

inspiratory reserve volume

Answer 5

extra volume of air that can be maximally inspired over and above the typical resting tidal volume

Question 6

expiratory reserve volume

Answer 6

extra volume of air that can be actively expired by maximal contraction beyond normal volume of air after resting tidal volume

Question 7

residual volume

Answer 7

minimum volume of air remaining in lungs even after maximum expiration

Question 8

functional residual capacity

Answer 8

volume of air in lungs at end of passive expiration

Question 9

vital capacity

Answer 9

maximum volume of air that can be moved out during a single breath following a maximal inspiration

Question 10

total lung capacity

Answer 10

Total volume of air that the lungs can hold

Question 11

inspiratory capacity

Answer 11

maximum volume of air that can be inspired at the end of a normal quiet expiration

Question 12

can residual volume be measured by spirometry?

Answer 12

residual volume CANNOT be measured by this piece of apparatus

Question 13

whats the effects on residual volume when the elastic recoil of the lungs is lost

Answer 13

residual volume increases/worsens

Question 14

what is forced vital capacity (FVC)

Answer 14

maximum volume that can be forcibly expelled from lungs following maximum inspiration

Question 15

what is FEV1

Answer 15

forced expiratory volume in one second

Question 16

what is FEV1/FVC ratio

Answer 16

the proportion of forced vital capacity that can be expired in the first second

Question 17

what is the primary determinant of airway resistance?

Answer 17

radius of the conducting airway

Question 18

name 5 factors that affect airway resistance

Answer 18

1) lung volume
2) bronchial smooth muscle tone
3) type of airflow
4) gas density & viscosity
5) dynamic airway collapse

Question 19

what would you need to do to lung volume to decrease airway resistance?

Answer 19

BACKGROUD

• bronchi are supported by lung tissue
• increasing volume of lung tissue, decreases resistance as the diameter is increased

Question 20

what type of bronchial smooth muscle causes contraction and what causes dilation and thus which causes more & less resistance?

Answer 20

PARAsympathetic = bronchoCONSTRICTION, most resistance

Sympathetic = bronchoDILATION, increasing airway diameter, decreased resistance

Question 21

what type of airflow causes less resistance and what causes the most?

Answer 21

1) laminar flow causes less = air molecules move parallel down bronchi
2) bronchi causes more = air molecule move in a disordered fashion

Question 22

describe what effect to gas density & viscosity increases resistance?

Answer 22

increasing gas density & viscosity increases resistance

Question 23

what is dynamic airway compression?

Answer 23

the rising pleural pressure during active expiration which compresses the alveoli & airway

Question 24

explain the effect dynamic airway compression has on normal healthy people.

Answer 24

• it causes no problems
• increased airway resistance causes an increase in airway pressure upstream
• helping open the airways by increasing the driving pressure between the alveolus & airway

Question 25

explain the effect of dynamic airway compression if there is an airway OBSTRUCTION.

Answer 25

- if there is an obstruction, the driving pressure between alveolus & airway is lost - causing a fall in airway pressure along the airway downstream resulting in airway compression by rising pleural pressure during active expiration

Question 26

what effect does disease have on airways?

Answer 26

diseased airways are more likely to COLLAPSE

Question 27

what is pulmonary compliance

Answer 27

measure of the effort that has to go into stretching or distending the lungs/chest walls

Question 28

what 2 factors affect pulmonary compliance

Answer 28

1) elasticity | 2) surface tension

Question 29

if the lungs are less compliant, what does that mean in terms of work required?

Answer 29

more work is required to produce a degree of inflation

Question 30

5 things that decrease pulmonary compliance?

Answer 30

1) pulmonary fibrosis 2) pulmonary oedema 3) collapsed lung 4) pneumonia 5) absence of surfactant

Question 31

2 factors which increase pulmonary compliance

Answer 31

1) elastic recoil of lung is lost (easier to inflate) | 2) increases with age

Question 32

what disease is associated with increased compliance

Answer 32

EMPHYSEMA - elastic tissue is lost, so patients have no problem inhaling and inflating the lugs but more effort is needed to exhale. leading to hyperinflation.

Question 33

what does work of breathing refer to?

Answer 33

amount of effort needed to expand the lungs

Question 34

what is work of breathing

Answer 34

amount of effort needed to expand the lungs

Question 35

3 factors which increase work of breathing in people with lung diseases

Answer 35

1) lung volumes - low lung volumes, the airways marrows & therefore increase resistance 2) airway obstruction - increase airway resistance - increasing work of breathing 3) restrictive chest wall or lung disease (e.g. obesity) - increase the effort required to stretch the chest wall & thus increase the work of breathing

Question 36

give 4 scenarios where work of breathing is increased

Answer 36

1) pulmonary compliance is decreased 2) airway resistance increased 3) elastic recoil decreased 4) need for increased ventilation