Respiratory Physiology I

Question 1

What does the conducting zone of the respiratory system do to the air being breathed in?

Answer 1

Passes air to the site of gas exchange

Filters, humidifies, and warms the air

Question 2

What does the respiratory zone do?

Answer 2

It is the site of gas exchange

Question 3

What is the respiratory zone composed of?

Answer 3

Respiratory bronchioles

Alveolar ducts

Alveolar sacs

Question 4

Why are alveoli so small and numerous?

Answer 4

To great a huge surface area for gas exchange.

Question 5

What happens in the resiratory zone?

Answer 5

An “Air-blood barrier” creates a membrane for gas exchange through which oxygen diffuses from air into alveolus to blood in capillary.

Carbon dioxide diffuses from the blood in capillary to air in the alveolus

Question 6

What percentage of alveolar surface is covered in capillaries?

Answer 6

80%

Question 7

What percentage of cardiac output reaches the capillaries in alveoli?

Answer 7

100%

Question 8

What lies between capillaries and alveoli?

Answer 8

Basal lamina which fuses them together

Question 9

What pleurae cover the lungs?

Answer 9

Visceral and parietal pleurae.

Question 10

What do pleurae do?

Answer 10

Reduce friction

Create suction

Compartmentalization (prevent infection)

Question 11

How do pleurae reduce friction ?

Answer 11

They form a fluid rich layer over the lungs which allows them to slide on each other.

Question 12

How do pleurae help with ventilation air intake?

Answer 12

They create a chamber for expansion of chamber

Question 13

How do pleurae prevent infection?

Answer 13

They compartmentalize the lungs into separate chambers to prevent spread of infection

Question 14

What does Boyle’s law state?

Answer 14

Gas pressure in closed container is inversely proportional to volume of the container.

Gas will flow from regions of high pressure to regions of low pressure.

There, to get air into alveoli their pressure must be lower than atmospheric pressure.

This is accompanied by increased chest volume.

Question 15

What muscles are involved in quiet breathing inspiration?

Answer 15

Diaphragm only, intercostals are also active in inspiration

Question 16

How does expiration occur?

Answer 16

It is mostly passive relying on the recoil of thoracic muscles

Question 17

What muscles are incorporated in forced breathing inspiration?

Answer 17

Diaphragm, pectoral muscles, scalene, and sternocleidomastoid muscles.

Question 18

What muscles are incorporated into forced expiration?

Answer 18

Internal intercostals, transverse thoracic muscles, rectus abdominus, external oblique transversus abdominus

Pelvic floor muscles must be active too to equalize pressure

Question 19

How is pressure chainging in our alveoli?

Answer 19

Intrapleural pressure. When breathing in the lungs are being sucked out into the chest cage by the change in pressure. The pleura counter that by expanding all the way to the cage before the stage where the lung collapses in on itself.

Question 20

Where must pressure always be maintained at negative pressure?

Answer 20

Transairway pressure and Intrapleural pressure

Question 21

What pressure difference is maintained between the alveoli and the atmosphere?

Answer 21

About 4 - 5 mmHg

Question 22

How does air flow into lungs?

Answer 22

Contraction of diaphragm causes pressure in ribcage to drop.

Dropping pressure in ribcage causes intraplueral pressur to drop

Dropping pressure in the intrapleural space moves the pleura away from the alveoli towards the ribcage thus causing the alveoli to expand and drop in pressure.

Low pressure in alveoli sucks air in

Question 23

What does spirometry measure?

Answer 23

Volume of air entering and leaving the lungs during inspiration and expiration.

Question 24

Forced expiration doesn’t bring lung volume to 0. What is the remaining volume of air called?

Answer 24

Residual Volume

Question 25

What is normal breathing volume called?

Answer 25

Tidal volume

Question 26

What is inspiratory reserve volume?

Answer 26

The difference in volume between maximum possible inspiration and the maximum tidal volume.

Question 27

What is expiratory reserve volume?

Answer 27

The difference between the tidal volume minimum and the minimum forced volume.

Question 28

What is the average tidal volume of males and females?

Answer 28

500ml for both

Question 29

What is the average forced inspiration for males?

Answer 29

3100ml

Question 30

What is inspiratory capacity?

Answer 30

Inspiratory reserve volume + tidal volume

Question 31

What is average residual volume in males?

Answer 31

1200 mls

Question 32

What is average total lung capacity in males?

Answer 32

6000mls

Question 33

What is the vital capacity for males (inspiratory capacity plus expiratory reserve volume)?

Answer 33

4800mls

Question 34

What does vital capacity refer to?

Answer 34

Maximum amount of air that can be expired after a maximum inspiratory effort

Question 35

Can residual volume be measured with spirometry?

Answer 35

No

Question 36

How is residual volume measured?

Answer 36

Helium dilution or other advanced techniques

Question 37

What is the minimum voluntary deflation called?

Answer 37

Residual volume

Question 38

What is dead space volume?

Answer 38

Volume of air that doesn’t reach the alveoli

Question 39

How can ventilation be used to increase amount of oxygen that reaches the blood?

Answer 39

Increasing Ventilation frequency

Increasing tidal volume

Question 40

Tidal Volume X Frequency =

Answer 40

Ventilation

Question 41

What is necessary to exclude when calculating alveolar ventilation?

Answer 41

The dead space volume

Question 42

What is normal alveolar ventillation rate?

Answer 42

5.25 L/min compared to minute ventilation 7.5L/min

Question 43

What is more efficient to increase, frequency or tidal volume?

Answer 43

Tidal volume because dead space works against us

Question 44

What is the effect of rapid shallow breathing?

Answer 44

Alveolar ventilation drops