Introduction to Respiration

Question 1

What doesn’t change regardless of the concentration of O2?

Answer 1

Partial pressure in different environments - Air, Water, Blood

Question 2

How does gas move? According to partial pressure or according to concentration?

Answer 2

Partial pressure from high to low

Question 3

What is the partial pressure in the alveolus?

Answer 3

100mmHg

Question 4

What is the concentration of O2 in the alveolus?

Answer 4

0.3mlO2/100ml blood

Question 5

What is the partial pressure in the mixed venous blood?

Answer 5

40mmHg

Question 6

What is the concentration of O2 in the blood?

Answer 6

15.8mlO2/100ml blood

Question 7

Why does O2 move according to partial pressure and not concentration?

Answer 7

if it moved according to concentration then O2 would flow out of the body and we would die

Question 8

What is the partial pressure in dry room air?

Answer 8

159 mmHg

Question 9

What is the partial pressure in tracheal gas?

Answer 9

149mmHg

Question 10

What is the partial pressure in alveolar gas?

Answer 10

100mmHg

Question 11

What is the partial pressure of pulmonary veinous blood?

Answer 11

98mmHg

Question 12

What type of epithelial cell is the Type 1 alveolar?

Answer 12

squamous epithelial for thin blood gas barrier

Question 13

What type of epithelial cell is the type 2 alveolar?

Answer 13

cuboidal - stem cell for type 1, produces mucus and surfactant

Question 14

What is the significance of alveolar branching?

Answer 14

it reduces resistance throughout the branch network as the diameter narrows
increases the area for gas exchange

Question 15

What is the law associated with resistance in the airway?

Answer 15

Poiseuille’s Law

R= 8nl/(pi)r4

Question 16

What does a doubling of total airway diameter do?

Answer 16

reduces resistance 16-fold

Question 17

When does gas move into the alveoli?

Answer 17

alveolar pressure is less than atmospheric

airways are open

Question 18

When does gas move out of the alveoli?

Answer 18

alveolar pressure is greater than atmospheric

airways are open

Question 19

What is alveolar pressure the sum of?

Answer 19

elastic recoil pressure

pleural pressure

Question 20

What are the main inspiratory muscles?

Answer 20

Diaphragm
External intercostals
Accessory muscles

Question 21

How is the diaphragm innervated?

Answer 21

phrenic nerves C3-5

Question 22

How are the external intercostals innervated?

Answer 22

intercostal nerves at the rib level

Question 23

What are the accessory muscles?

Answer 23

sternocleidomastoid, scalenes

Question 24

As the chest expands, what happens to intrapleural pressure?

Answer 24

it falls

Question 25

What are the muscles involved in forced expiration?

Answer 25

internal intercostals | abdominal wall

Question 26

What are some of the vital volumes and capacities?

Answer 26

``` Vt - tidal volume FEV - forced expired volume FRC ERV IRV Residual volume ```

Question 27

What is the typical pulmonary volume in males and females?

Answer 27

6L in males | 4.2L in females

Question 28

How do you calculate vital capacity?

Answer 28

IRV+Vt+ERV

Question 29

How do you calculate the FRC?

Answer 29

ERV and residual volum

Question 30

How do you calculate the inspiratory capacity?

Answer 30

IRV and Vt

Question 31

How do you measure the FRC?

Answer 31

helium inhalation method V2 = V1(C1-C2)/C2 Take known concentration of helium in tank of known volume, take concentration after breathing

Question 32

What is anatomical dead space?

Answer 32

component of the lung that does not participate in gas exchange airway, nasal cavity and mouth

Question 33

How may anatomical dead space vary?

Answer 33

Disease mechanical ventilation alveolar collapse species

Question 34

How can you measure anatomical dead space?

Answer 34

O2 inhalation method | Carbon dioxide dilution method

Question 35

How does the oxygen inhalation method work?

Answer 35

single inspiration of O2 o2 flushes out the gas in the lung which is composed of 75% N2 As subject exhales the breath is initially O2 rich but eventually equilibriates with O2, when a=b that is the dead space

Question 36

How does the CO2 dilution method work?

Answer 36

Dead space dilutes the CO2 | Vd/Vt = PaCO2 - PexpCO2/PaCO2

Question 37

What is considered a normal FEV1?

Answer 37

80% of FVC

Question 38

What is FVC?

Answer 38

maximum exhalation under forced conditions

Question 39

What is FEV1?

Answer 39

amount of air exhaled in 1s

Question 40

What would be the expected FEV in asthmatics and emphysema?

Answer 40

42% ish

Question 41

What would be the expected FEV in restrictive diseases like pulmonary fibrosis?

Answer 41

90%