lecture 15 - respiratory system 2

Question 1

what is elasticity?

Answer 1

ability of tissue to return to its original state when stretched

Question 2

what influences the overall effectiveness of pulmonary ventilation?

Answer 2

airway resistance

alveolar surface tension

lung compliance

Question 3

what is airway resistance?

Answer 3

defined as anything that impedes air flow through the respiratory tract

Question 4

what is alveolar surface tension?

Answer 4

alveoli are converted with thin film of liquid composed mainly of water creating gas-water boundaries

Question 5

what is lung compliance?

Answer 5

refers to the ability of lungs and chest wall to stretch

Question 6

which part of the respiratory tract has the highest resistance?

Answer 6

bronchi

as generation increases
• resistance decreases
• SA increases

Question 7

when does resistance increase?

Answer 7

inflammation of airways

increased mucus secretion

presence of tumour

Question 8

what is the diameter of bronchioles controlled by?

Answer 8

ANS - parasympathetic

• bronchoconstriction increases resistance

Question 9

how does alveolar surface tension change?

Answer 9

greatest when alveoli are at their smallest diameter - during expiration

increases surface tension resists the ability of the alveolus to inflate

Question 10

law of LaPlace in alveoli

Answer 10

smaller radius = higher pressure

more difficult to inflate - need to have a higher pressure

small alveolar are more difficult to inflate than larger ones

surfactant reduces surface tension

Question 11

how does surfactant reduce surface tension?

Answer 11

without surfactant, H bonds pull the water molecules together and the alveolus collapses

with surfactant, the H bonds are disrupted and the alveolus remain inflated

Question 12

what is surfactant produced by?

Answer 12

type 2 alveolar cells

Question 13

what is surfactant?

Answer 13

mixture containing proteins and phospholipids

polar and non-polar end

disrupts cohesive force of H bonds in water

more concentrated in small alveoli - increase stability

Question 14

what is compliance?

Answer 14

defined as a change in volume produced by a change in pressure

low compliance = hard to stretch

high compliance = easy to stretch

Question 15

what is compliance affected by?

Answer 15

alveolar surface tension - surfactant increases compliance

distensability of elastic tissue of lung

ability of chests all to move or stretch in inspiration

as you increase pressure, volume in the lungs increase

Question 16

what is tidal volume (TV)?

Answer 16

volume inspired or expired with each normal breath

500 ml

Question 17

what is expiratory reserve volume (ERV)?

Answer 17

maximal volume that can be expired after tidal volume

1200 ml

Question 18

what is inspiratory reserve volume (IRV)?

Answer 18

maximal volume that can be inspired after tidal volume

3100 ml

Question 19

what is residual volume (RV)?

Answer 19

volume that remains in the lungs after maximal expiration

1200 ml

Question 20

what is inspiratory capacity (IC)?

Answer 20

volume of maximal inspiration

TV + IRV

3600 ml

Question 21

what is functional residual capacity (FRC)?

Answer 21

volume of gas remaining in the lung after normal expiration

ERV + EV

2400 ml

Question 22

what is vital capacity (VC)?

Answer 22

volume of maximal inspiration and expiration

IRV+ TV + ERV = IC + ERV

4800 ml

Question 23

what is total lung capacity (TLC)?

Answer 23

the volume of the lung after maximal inspiration

the sum of all 4 lung volumes

Question 24

what is forced vital capacity (FVC)?

Answer 24

amount of air you can get in your lungs

Question 25

what is FEV1?

Answer 25

forced expiratory volume in 1 second

Question 26

how do changes in FVC and FEV1 indicate disease?

Answer 26

a healthy person should exhale about 80% of vital capacity in 1 second

Question 27

what indicates an obstructive lung disease?

Answer 27

FVC close to normal FEV1 reduces asthma bronchitis

Question 28

what indicates a restrictive lung disease?

Answer 28

FVC reduces FEV1 close to normal pulmonary fibrosis

Question 29

what are non-respiratory movements not intended for ventilation?

Answer 29

sigh yawn sneeze cough

Question 30

sigh

Answer 30

slow, deep expiration held and followed by slow expiration reopens local groups of collapsed alveoli stimulates release of surfactant

Question 31

yawn

Answer 31

large sigh takes lung volume ti inspiratory capacity when tired, minuses alveolar collapse during sleep after sleep, opens alveoli that collapsed during sleep

Question 32

sneeze

Answer 32

deep inspiration followed by large forceful expiration through nose clears foreign or irritating substances velocity of 100mph

Question 33

cough

Answer 33

similar to sneeze but initial inspiration is small or absent clears larnynx, trachea or lower airways velocity can be up to 500mph

Question 34

what is dead space?

Answer 34

areas that don't contribute to gas exchange

Question 35

anatomical dead space

Answer 35

volume of the conducting airways

Question 36

alveolar dead space

Answer 36

in unhealthy or elderly people not all alveoli function properly

Question 37

physiologic dead space

Answer 37

anatomic dead space + alveolar dead space

Question 38

what is total pulmonary ventilation?

Answer 38

ventilation rate x tidal volume (TV) greater than alveolar ventilation due to dead space

Question 39

why is alveolar ventilation a better measure?

Answer 39

better indication of how much fresh air reaches the alveoli = ventilation rate x (TV - dead space volume)