Chapter 19.3 Pulmonary Ventilation-Respiratory System

Question 1

What cavity are lungs in?

Answer 1

thoracic cavity

Question 2

why is closed compartment of thoratic cavity necessary?

Answer 2

Because it is to regulate air pressure inside lungs

Question 3

What Muscles used for quiet breathing-Inspiration?

Answer 3

diaphragm and external intercostals

Question 4

What Muscles used for quiet breathing-Expiration?

Answer 4

diaphragm and intercostals relax

Question 5

What does Intrapleural/alveolar pressure cause?

Answer 5

causes air to move in or out of lungs

Question 6

When would air moves in in terms of Intrapleural/alveolar
pressure?

Answer 6

When it’s decreased pressure

Question 7

When would air moves out in terms of Intrapleural/alveolar
pressure?

Answer 7

When it’s increased pressure

Question 8

What would happen to Sternocleidomastoid during forced inhalation?

Answer 8

Sternocleidomastoid contracts to elevate sternum and clavicles

Question 9

What would happen to Scalenes during forced inhalation?

Answer 9

Scalenes elevate upper ribs

Question 10

What happens during a severe asthma attack?

Answer 10

possible to contract pectoralis muscles which are connected to sternum and humerus
and that is why someone enduring asthma attack will be raising their shoulders to try to further increase lung volume

Question 11

What is Boyle’s law?

Answer 11

at constant temperature, pressure of gas varies inversely with its volume

Question 12

What is equation for Boyle’s law?

Answer 12

P1V1 = P2V2

Question 13

Will gases always fill their container?

Answer 13

Yes

Question 14

What would distance be for molecules in large container?

Answer 14

molecules in given amount of gas will be far apart (low pressure)

Question 15

What would distance be for molecules in smaller container?

Answer 15

same amount of gas in smaller container compared to amount in large container will have molecules close together (high pressure)

Question 16

What does change in volume cause?

Answer 16

Causes change in pressure

Question 17

What does change in pressure lead to?

Answer 17

Leads to air flow to equalize pressure

Question 18

What is ventilation?

Answer 18

exchange of air between atmosphere and alveoli

Question 19

What is equation for flow?

Answer 19

F = △P/R

Question 20

What is flow (F) propotional to?

Answer 20

Proportional to pressure difference (Δ P) between two points

Question 21

What is flow (F) inversely propotional to?

Answer 21

Inversely proportional to resistance (R)

Question 22

Why does air always flow towards ‘smaller airways with greater surface area’?

Answer 22

Because Air flows toward lower pressure

Question 23

What are respiratory relative to?

Answer 23

relative to atmospheric pressure

Question 24

What is atmospheric pressure measured in?

Answer 24

Measured in mmHg or atmospheres (atm)

Question 25

What would atmospheric pressure at sea level and higher altitudes

Answer 25

At sea level: 760 mmHg or 1 atm
At higher altitudes: Lower pressure

Question 26

What does Intrapleural pressure fluctuates with?

Answer 26

fluctuates with breathing

Question 27

How much pressure is intrapleural pressure compared to alveolar pressure

Answer 27

it always ~4 mmHg less than alveolar pressure

Question 28

What happens if If intrapleural pressure=alveolar pressure

Answer 28

No force holding alveoli open
Lungs would collapse

Question 29

What happens to Intrapleural pressure if lung is punctured

Answer 29

Intrapleural pressure cannot be maintained

Question 30

What pressure needs to be if lung is punctured

Answer 30

Needs to be lower than alveolar pressure (like vacuum) to ensure that visceral pleura stays connected to parietal pleura

Question 31

What is Punctured lungs that equalize alveolar and intrapleural pressure called and what happens to lung

Answer 31

It is called pneumothorax, and lung will deflate

Question 32

What can compliance be considered?

Answer 32

inverse of stiffness

Question 33

What comes after greater lung compliance

Answer 33

Easier it is to expand lungs

Question 34

What are two major determinants of lung compliance

Answer 34

1. Stretchability of lung tissues
2. Surface tension at air-water interfaces within alveoli – surfactant

Question 35

What is required for lungs to push air out of lungs during exhalation

Answer 35

Recoil

Question 36

What does type II alveolar cells secrete?

Answer 36

They secrete surfactant

Question 37

What would type ll alveolar cells secreting surfactant cause?

Answer 37

Reduces cohesive forces between water molecules on alveolar surface, lowers surface tension,
increases lung compliance,
and makes it easier to expand lungs

Question 38

How do you calculate Alveolar ventilation

Answer 38

Alveolar ventilation = (tidal volume – dead space) x respiration rate

Question 39

What size is dead space for adult and children

Answer 39

Dead space = ~150 ml in adults and ~100 ml in children

Question 40

When do we have alveolar dead space

Answer 40

When some alveoli have less blood flow at that time

Question 41

What size is alveolar dead space for normal and sick people

Answer 41

Normally small in healthy people, someone with lung cancer would have much higher alveolar dead space