Respiratory Physiology

Question 1

Respiratory pressures are described relative to

Answer 1

atmospheric pressures

Question 2

Alveolar (intrapulmonary) pressure is

Answer 2

Pressure in the alveoli that rises/falls during respiration to eventually equalize with atmospheric pressure

Question 3

Intrapleural pressure is

Answer 3

The pressure between the visceral and parietal pleura that is always less that alveolar to keep lungs inflated by creating a vacuum

Question 4

Negative intrapleural pressure is due to the opposing forces of

Answer 4

• recoil force & surface tension of
  alveolar fluid in lungs: pulls lungs
  away from thorax
• natural tendency of the chest wall to pull outwards: pulls thorax outward & enlarge lungs

Question 5

Transpulmonary pressure is

Answer 5

The difference between the alveolar & intrapleural pressures

Question 6

Greater transpulmonary pressure equals

Answer 6

larger lung volume

Question 7

Boyle’s law:

Answer 7

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

Question 8

Pulmonary ventilation is

Answer 8

The mechanical process of gas flow into & out of the lungs

Question 9

Air flows to areas of

Answer 9

Low pressure

Question 10

Quiet inspiration is

Answer 10

(At rest) The diaphragm & intercostal muscles contracting
- ↑ thoracic volume → alveolar pressure < Patm →
air flows into lungs

Question 11

Forced inspiration is

Answer 11

(Deep breathing) The accessory muscles of neck & thorax contracting
- greater↑ thoracic volume than during quiet inspiration → greater air flow into the lungs
- further decreased pressure in lungs allows more air to move into them

Question 12

Quiet expiration is

Answer 12

A passive process relying on the elastic recoil of lungs as thoracic muscles & diaphragm relax
- ↓ thoracic volume → alveolar pressure > Patm
→ air flows out of lungs

Question 13

Forced expiration is

Answer 13

An active process relying on the contraction of abdominal muscles to↑ intra-abdominal pressure & depress rib cage
- contracting abdominal muscles makes volume smaller which increases the pressure and pushes more air out of the lungs.

Question 14

Tidal volume is

Answer 14

The amount of air that moves in & out
of lungs with each breath during quiet breathing (~ 500 ml/breath)

Question 15

Inspiratory reserve volume (IRV) is

Answer 15

The amount of air that can be inspired beyond the tidal volume

Question 16

Expiratory reserve volume (ERV) is

Answer 16

The amount of air that can be evacuated
from the lungs after tidal expiration

Question 17

Vital capacity (VC) is

Answer 17

The total amount of exchangeable air / max amount that you can move in and out of lungs

Question 18

Residual volume

Answer 18

The amount of air remaining in lungs after maximal forced expiration

Question 19

Total lung capacity is

Answer 19

The sum of all lung volumes

Question 20

Anatomical dead space is

Answer 20

The volume of the conducting zone conduits that don’t contribute to gas exchange in lungs (~150 ml)

Question 21

Amount of gas that will dissolve in a liquid depends on

Answer 21

The partial pressure of the gas in contact with the liquid, the solubility of the gas in liquid, and temperature of the liquid

Question 22

Gas that diffuses rapidly from alveoli to blood

Answer 22

O2

Question 23

Gas that diffuses from blood to alveoli along a partial pressure gradient that is less steep

Answer 23

CO2

Question 24

Alveolar gas differ from atmospheric gas due to

Answer 24

• gas exchange occurring in the lungs
• humidification of air by conducting passages
• mixing of alveolar gas with each breath

Question 25

Respiratory membrane provides

Answer 25

Efficient SA for gas exchange (very thin w/huge SA)

Question 26

Ventilation and perfusion are

Answer 26

Balanced so that O2 & CO2 levels match physiological demands

Question 27

Perfusion is controlled by

Answer 27

O2 pressure changing the arteriolar diameter

Question 28

Ventilation is controlled by

Answer 28

CO2 pressure changing the bronchiolar diameter

Question 29

Internal respiration is

Answer 29

Capillary gas exchange in body tissues (once blood has traveled to the tissues)

Question 30

External respiration takes place between

Answer 30

The alveoli and blood

Question 31

O2 is not very soluble in blood, 98.5% is carried by

Answer 31

Hemoglobin

Question 32

Iron binds to

Answer 32

O2

Question 33

1 hemoglobin can bind

Answer 33

4 O2 molecules

Question 34

High affinity occurs at

Answer 34

High Ο2 levels

Question 35

At low O2 levels

Answer 35

Hemoglobin wants to offload O2

Question 36

The larger the difference between tissue O2 and blood O2

Answer 36

The more easily O2 detaches from hemoglobin to diffuse into the tissue

Question 37

At high O2 pressure

Answer 37

The O2 saturation curve is flat; hemoglobin saturation of O2 is stable;
- O2 has to go down a lot to affect hemoglobin saturation

Question 38

At low O2 pressure

Answer 38

hemoglobin easily releases O2

Question 39

7-10% of CO2 is transported in the blood via

Answer 39

Dissolving in plasma

Question 40

20% of CO2 is transported in the blood via

Answer 40

Being carried on globins of hemoglobin

Question 41

70% of CO2 is transported in the blood

Answer 41

As bicarbonate ions

Question 42

As blood CO2 increases

Answer 42

pH decreases (more acidic)
- slow shallow breathing

Question 43

As blood CO2 decreases

Answer 43

pH increases (less acidic)
- rapid, deep breathing