L9.2 Respiratory System II

Question 1

what are physical factors influencing ventilation?

Answer 1

• airway resistance
• alveolar surface tension
• lung compliance and elastic recoil

Question 2

what does the airflow rate depend on?

Answer 2

• air pressure gradient (difference between atmospheric and intra-alveolar pressure)
• airway resistance

Question 3

airway resistance is _____ in healthy individuals

Answer 3

airway resistance is VERY LOW in healthy individuals

Question 4

increased airway resistance =?

Answer 4

increased airway resistance = slower airflow

Question 5

main factor increasing airway resistance is …

Answer 5

main factor increasing airway resistance is REDUCED BRONCHIOLE RADIUS

Question 6

alveoli are lined with a layer of water which creates _____
this can cause alveoli to ____ (___)
resists ____ of alveoli (___)

Answer 6

alveoli are lined with a layer of water which creates SURFACE TENSION
this can cause alveoli to COLLAPSE (EXPIRATION)
resists INFLATION of alveoli (INSPIRATION)

Question 7

what is the law of LaPlace

Answer 7

P = 2T/R
- the magnitude of inward-direction pressure (P) is directly proportional to the surface tension (T) and inversely proportional to the radius (R) of the alveolus

Question 8

the collapsibility of an alveolus can be reduced by ______ the surface tension

Answer 8

the collapsibility of an alveolus can be reduced by DECREASING the surface tension

Question 9

what is surfactant? and its purposes?

Answer 9

surfactant breaks the surface tension of water (produced by type II alveolar cells; mixture of protein and lipids)
breaks hydrogen bonds between water molecules (stops alveoli from collapsing; easier to expand alveoli during inspiration)

Question 10

what is lung compliance?
high compliance = ?
low compliance = ?

Answer 10

stretchability of the lungs during inspiration
high compliance = easily stretched
low compliance = hard to stretch

Question 11

what are factors reducing compliance?

Answer 11

• high surface tension (reduced surfactant)

- scarring of lung tissue

Question 12

what is elastic recoil?

Answer 12

• ability of lungs to rebound (shrink)

- important during expiration

Question 13

elastic recoil is influenced by two factors: ? and ?

Answer 13

• elastic fibres

- surface tension (decrease surface tension = decrease elastic recoil)

Question 14

define tidal volume

Answer 14

air inspired or expired during quiet breathing

Question 15

define inspiratory reserve volume

Answer 15

extra air inspired during forced inpsiration

Question 16

define expiratory reserve volume

Answer 16

extra air expired during forced expiration

Question 17

define residual volume

Answer 17

air left in the lungs after forced expiration

Question 18

define inspiratory capacity

Answer 18

maximum volume of air that can be inspired

TV + IRV

Question 19

define vital capacity

Answer 19

maximum amount of air expired after maximum inspiration

TV + IRV + ERV

Question 20

define functional residual capacity

Answer 20

volume of air in lungs after normal expiration

ERV + RV

Question 21

define total lung capacity

Answer 21

maximum volume of air that the lungs can hold

VC + RV

Question 22

what is pulmonary ventilation

Answer 22

volume of air breathed in and out per minute

pulmonary ventilation = tidal volume X respiratory rate

Question 23

would it be better for an athlete to increase the tidal volume or the respiratory rate?

Answer 23

take bigger breaths (tidal volume) because dead space is lost with every breath, it is more efficient to increase ventilation by increasing tidal volume

Question 24

what is anatomical dead space?

Answer 24

the volume of air available for gas exchange is less than the tidal volume BC some of the tidal volume never makes it into the alveoli

anatomical dead space = air stuck in the airways

Question 25

what is alveolar ventilation?

Answer 25

volume of air exchanged between the atmosphere and alveoli = air available for gas exchange; takes dead space into account

alveolar ventilation = (tidal volume - dead space) X respiratory rate