Pulm: Ventilation

Question 1

What are the conducting airways?

Answer 1

• upper airways
  
  • nasopharynx
  • oropharynx
• Larynx- connects upper to lower
• lower airways
  
  • trachea
  • bronchi
  • terminal bronchioles

Question 2

What are the gas exchange airways?

Answer 2

• Respiratory bronchioles
• alveolar ducts
• alveoli

Question 3

What are Type I alveolar cells?

Answer 3

epithelial cells in the alveoli that allow for the gas exchange

Question 4

What are Type II alveolar cells?

Answer 4

Epithelial cells in the alveoli that produce surfactant

Question 5

What makes up the chest wall?

Answer 5

• skin
• ribs
• intercostal muscles
• thoracic cavity

Question 6

What is the Pleura?

Answer 6

• potential space between the lungs and the ribs
• serous membrane of simple stratified cells
• parietal layer is the outermost layer
• visceral layer is the innermost layer

Question 7

How many generations are there in the interpulmonary airways?

Answer 7

23

Question 8

How are the intrapulmonary airways subdivided?

Answer 8

• Bronchi
  
  • segmental bronchus
  • large subsegmental bronchi (about 5 generations)
  • small bronchi (about 15 generations)
• bronchioles
  
  • terminal bronchioles
  • respiratory bronchioles (beginning of gas exchange)
  • Alveolar ducts and alveolar sacs

Question 9

After which generation does the surface area of the airway significantly increase?

Answer 9

after the 10th generation

Question 10

describe the makeup of the trache and large bronchi

Answer 10

• lined mainly by pseudostratified columnar epithelium
• goblet cells- make mucus
• basal cells- pulmonary epithelial stem cells

Question 11

Which carries oxygenated blood?

Pulmonary artery or pulmonary vein?

Answer 11

The pulmonary artery brings the deoxygenated blood from the Right ventricle and the pulmonary vein brings the oxygenated blood back to the Left atrium

Question 12

Why is there some deoxygenated blood in the left side of the heart?

Answer 12

Oxygen is delivered to the terminal bronchioles by the bronchial artery which branches off the aorta. Once the O2 has been delivered to the terminal bronchiole, that blood joins the pulmonary vein which continues on to the left side of the heart.

Question 13

About how many alveoli do we have and what is the cross sectional area?

Answer 13

500 million alveoli

30-50 m²

Question 14

What is the significance of the pores of Kohn?

Answer 14

aka Alveolar pore. Allows air to move from one alveoli to another like a little side door. This is important because the alveoli are so small that if a piece of dust entered the airway it could block of one or many alveoli and without gas entering they would collapse. The pores of Kohn allow air to still enter those alveoli so they do not collapse until the dust can be removed.

Question 15

V_T

Answer 15

Tidal volume

the volume of air inhaled during normal breathing

At rest, usually about 500 ml

Question 16

Residual volume

Answer 16

The volume remaining in the lungs after a maximal exhalation

Question 17

Expiratory reserve volume

Answer 17

the additional volume a person is capable of exhaling after a normal, quiet expiration

Question 18

Inspiratory reserve volume

Answer 18

The additional volume a person is able to inhale after a normal, quiet respiration

Question 19

Total lung capacity

Answer 19

The volume of gas in the lungs after maximal inspiration.

approx 7 L in healthy adults

TLC = IC + FRC

Question 20

Vital capacity

Answer 20

the maximum volume of air that a person can exhale after maximal inspiration.

Normal value about 5 L

VC =IRV + TV + ERV

Question 21

Functional residual capacity

Answer 21

The volume remaining in the lungs after expiration during normal, quiet breathing.

FRC = ERV + RV

Question 22

IC

Answer 22

inspiratory capacity

IRV + TV

Question 23

How do you determine FRC with helium?

Answer 23

With Helium:

FRC = V_s x (C₁/C₂-1)

C_1/2 = concentration 1/2

V_s = volume of spirometer

Question 24

How do you determine FRC with whole body plethysmography?

Answer 24

• plethysmography uses an airtight booth, when person inhales, their volume goes up and so does pressure. Uses boyle’s law
• P₁ x V₁ = P₂ x V₂

Question 25

Ventilation definition

Answer 25

the movement of air in and out of the respiratory system.

During normal, quiet breathing, the amt inhaled and exhaled each breath is about 500 ml.

Question 26

V_E

Answer 26

V_E = minute ventilation, the total volume exhaled per minute

V_E = R x V_T

Question 27

V_A

Answer 27

Alveolar ventilation- ventilation of the respiratory zone of the lungs

V_A = R (V_T-V_D)

V_D = dead space ventilation

Question 28

Why is V_A less than V_E?

Answer 28

because part of the V_T remains in anatomic dead space and is not involved in gas exchange

Question 29

How is deadspace determined?

Answer 29

V_D= V_T x (Pa_CO2-PE_CO2)/(Pa_CO2)

PE_CO2 = expired CO₂ at the mouth

Question 30

Does P_ACO2 equal P_aCO2?

Answer 30

Yes, because Alveolar CO₂ equilibrates with arterial CO₂ in about 0.75 seconds, we can assume they are equal.

Question 31

What is the respiratory exchange quotient?

Answer 31

0.8

For every O₂ inhaled, 0.8 CO₂ are exhaled

Question 32

How do you calculate P_O2 of room air at sea level?

Answer 32

P_O2 = 0.21 x 760 mmHg = 160 mmHg

Question 33

How do you calculate PI_O2 in the trachea?

PI_O2 = inspired gas

Answer 33

PI_O2 = 0.21 x (760-47) mmHg = 150 mmHg

Question 34

How do you calculate the composition of alveolar gas?

Answer 34

P_AO2 = (PI_O2 - P_ACO2)/R

R = Respiratory exchange quotient = 0.8

Question 35

What is the Alveolar-Arterial gradient?

normal value?

Answer 35

P_AO2-P_aO2 = Alveolar-Arterial gradient

normally 5-10 mmHg

Question 36

How would your alveolo-arterial gradient reflect a problem with diffusion?

Answer 36

the gradient would be bigger than 10 mmHg

Question 37

How would your alveolo-arterial gradient relect a problem with ventilation?

Answer 37

both the P_AO2 and the P_aO2 would go down equally with a ventilation problem. The gradient would stay the same.