Respiration - Lecture 7

Question 1

What can the respiratory system be regarded as?

Answer 1

a pump with elastic, flow-resistive and inertial properties

Question 2

What happens to the FRC and Ppl of the lungs at rest?

Answer 2

they are negative due to the opposite forces acting on the lungs and chest wall

Question 3

What happens to the diaphragm and chest wall during inspiration?

Answer 3

the diaphragm contracts and the chest wall is pulled open

Question 4

What happens to the Ppl during inspiration?

Answer 4

it becomes more negative

Question 5

What is the formula for flow of breath?

Answer 5

F = (Palv - Patm)/Resistance

Question 6

The resting position of the lungs is below…

Answer 6

RV

Question 7

As the lungs are pulled further away from their resting position, what happens to Ppl?

Answer 7

it becomes even more sub atmospheric

Question 8

As the volume of the lungs is ____, gas in the lungs is ____, Palv drops _____ atmospheric pressure.

Answer 8

increased, decompressed, below

Question 9

What generates air flow to the lungs during inspiration?

Answer 9

the created negative pressure gradient between the alveoli and atmosphere

Question 10

What happens to the pressure gradient and the air flow as inspiration proceeds?

Answer 10

they gradually decrease

Question 11

Why does air flow stop at the end of inspiration?

Answer 11

because Palv is equal to Patm (no pressure gradient)

Question 12

During expiration, the diaphragm _____, elastic recoil of the respiratory system ____ the gas in the lungs, and Palv ____.

Answer 12

relaxes, compresses, increases

Question 13

What happens to the positive pressure gradient between the atmosphere and the lungs during expiration?

Answer 13

it causes air from the lungs to be pushed out to the atmosphere

Question 14

What happens to Ppl as lung volume decreases during expiration?

Answer 14

it slowly returns to its resting level

Question 15

What is the air flow, Palv and Ppl at the end of expiration?

Answer 15

air flow = 0, Palv = 0, Ppl = -5

Question 16

What does the time course of changes in pleural pressure during inspiration and expiration depend on?

Answer 16

contraction of the diaphragm and airway resistance

Question 17

What must occur in order to have gas flow through the airways?

Answer 17

the pressure at the airway opening must be different from that in the alveoli

Question 18

What is the formula for the resistance of the airways to gas flow?

Answer 18

Raw = (Palv-Pao)/Flow

Question 19

A ___ diameter airway can carry a ___ flow for a given pressure difference.

Answer 19

large, large

Question 20

What is airway resistance related to?

Answer 20

airway caliber

Question 21

What happens to airway resistance during asthma?

Answer 21

it is high making breathing difficult

Question 22

When a subject inspires to TLC and exhales to RV, during expiration, flow ___ very rapidly to a ___ value and then ___ over the rest of expiration.

Answer 22

rises, high, declines

Question 23

Why is the descending portion of the flow-volume curve independent of effort?

Answer 23

because of the compression of the airways by intrathoracic pressure

Question 24

What are the values of airway pressure and intrapleural pressure before inspiration?

Answer 24

airway pressure: 0
intra pleural pressure: -5

Question 25

What happens to the airway pressure and intrapleural pressure during inspiration?

Answer 25

airway pressure and intrapleural pressures fall

Question 26

What are the values of airway pressure and airway transmural pressure at the end of inspiration?

Answer 26

airway pressure: 0 airway transmural pressure: 8

Question 27

What happens to the alveolar pressure and intrapleural pressure during forced expiration?

Answer 27

they increase

Question 28

Why is there a positive pressure tending to close the airways during forced expiration?

Answer 28

because of the pressure drop along the airways as flow beings

Question 29

Why does the positive pressure decrease when moving out of the lungs during forced expiration?

Answer 29

because the air is going down over airway resistance (friction)

Question 30

What kind of recoil is found in restrictive diseases like pulmonary fibrosis?

Answer 30

more recoil (stiff)

Question 31

What happens to the maximum flow rate and maximum volume exhaled in restrictive diseases?

Answer 31

they are reduced

Question 32

What happens to the flow rate in obstructive diseases?

Answer 32

it is very low

Question 33

What kind of recoil is found in obstructive diseases like emphysema?

Answer 33

no recoil

Question 34

What are the 7 steps of events during inspiration?

Answer 34

Diaphragm and intercostal muscles contract ↓ Thoracic cage expands ↓ Intrapleural pressure becomes more negative (subatmospheric) ↓ Transpulmonary pressure increases ↓ Lungs expands ↓ Alveolar pressure becomes subatmospheric ↓ Air flows into alveoli

Question 35

What are the 8 steps of events during expiration?

Answer 35

Diaphragm and external intercostal muscles stop contracting ↓ Chest wall moves inwards ↓ Intrapleural pressure goes back towards preinspiratory value ↓ Transpulmonary pressure goes back towards preinspiratory value ↓ Lung recoils towards preinspiratory volume ↓ Air in lungs is compressed ↓ Alveolar pressure becomes greater than atmospheric pressure ↓ Air flows out of the lungs

Question 36

What increases proportionally when exercise starts?

Answer 36

tidal volume and breathing frequency

Question 37

What happens to tidal volume?

Answer 37

it plateaus

Question 38

What happens to ventilatory rates during hard exercise?

Answer 38

they become high due to incremental increases in frequency

Question 39

Because of the increased breathing frequency, inspiratory and expiratory times ___ during progressive exercise but expiratory times ___ relatively more than inspiratory time.

Answer 39

decrease, fall

Question 40

Which flow rate increases more?

Answer 40

peak expiratory flow rate

Question 41

In both untrained and trained subjects, what increases linearly with metabolic rate?

Answer 41

minute ventilation

Question 42

How much does minute ventilation increase in both trained and untrained subjects?

Answer 42

50 to 60% of VO2 max

Question 43

Minute ventilation ___ at a rate disproportionately ___ than the change in VO2.

Answer 43

increases, greater

Question 44

An effect of endurance training is to ___ the ventilatory inflection point.

Answer 44

delay

Question 45

How much can resting values of minute ventilation increase during exercise in a fit individual?

Answer 45

35 folds

Question 46

How much can resting values of cardiac output increase during exercise in a fit individual?

Answer 46

5-6 folds

Question 47

Which increases more during exercise; minute ventilation or perfusion?

Answer 47

minute ventilation

Question 48

What is one of the reasons why ventilation is not believed to limit aerobic performance?

Answer 48

because there in an increase in Ve/Q

Question 49

What are the values of minute ventilation and perfusion in less fit individuals?

Answer 49

less than fit ones but the ratio will increase to a similar extent

Question 50

What is the alveolar surface area?

Answer 50

50 m^2

Question 51

What is the average blood volume?

Answer 51

5 L

Question 52

What percentage of blood volume is in the pulmonary system at any one time during maximal exercise?

Answer 52

4%

Question 53

What kind of response is there in the medullary ECF during exercise?

Answer 53

an alkaloid (increases pH) response

Question 54

What decreases the ventilatory response during exercise?

Answer 54

an increase in pH

Question 55

What receptors are mainly sensitive to changes in PO2, but are stimulated by increased PCO2 and decreased pH?

Answer 55

peripheral chemoreceptors

Question 56

What remains constant during exercise?

Answer 56

PaO2

Question 57

What decreases during exercise?

Answer 57

PaCO2 and arterial pH

Question 58

What increases the sensitivity of the peripheral chemoreceptors to CO2 and H+ during exercise?

Answer 58

the fluctuations in PaO2

Question 59

What do the peripheral mechanoreceptors do to minute ventilation during exercise?

Answer 59

it increases it slightly

Question 60

What is asthma?

Answer 60

chronic inflammatory disease of the airways

Question 61

What are the symptoms of asthma?

Answer 61

airway obstruction, enhances airway responsiveness to contractile agonists and/or allergens

Question 62

What is emphysema?

Answer 62

the enlargement of the air spaces due to the destruction of the walls of the alveoli

Question 63

What happens to airways in people with emphysema?

Answer 63

they collapse because of the loss of radial traction

Question 64

What happens to the lungs during emphysema?

Answer 64

they self-destruct, attacked by proteolytic enzymes secreted by leukocytes in response to factors

Question 65

What is fibrosis?

Answer 65

progressive distortion of the alveolar architecture with inflammation and accumulation of fibrotic tissue