Pulm: Ventilation Flashcards Preview

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Flashcards in Pulm: Ventilation Deck (38)
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1
Q

What are the conducting airways?

A
  • upper airways
    • nasopharynx
    • oropharynx
  • Larynx- connects upper to lower
  • lower airways
    • trachea
    • bronchi
    • terminal bronchioles
2
Q

What are the gas exchange airways?

A
  • Respiratory bronchioles
  • alveolar ducts
  • alveoli
3
Q

What are Type I alveolar cells?

A

epithelial cells in the alveoli that allow for the gas exchange

4
Q

What are Type II alveolar cells?

A

Epithelial cells in the alveoli that produce surfactant

5
Q

What makes up the chest wall?

A
  • skin
  • ribs
  • intercostal muscles
  • thoracic cavity
6
Q

What is the Pleura?

A
  • 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
7
Q

How many generations are there in the interpulmonary airways?

A

23

8
Q

How are the intrapulmonary airways subdivided?

A
  • 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
9
Q

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

A

after the 10th generation

10
Q

describe the makeup of the trache and large bronchi

A
  • lined mainly by pseudostratified columnar epithelium
  • goblet cells- make mucus
  • basal cells- pulmonary epithelial stem cells
11
Q

Which carries oxygenated blood?

Pulmonary artery or pulmonary vein?

A

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

12
Q

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

A

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.

13
Q

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

A

500 million alveoli

30-50 m2

14
Q

What is the significance of the pores of Kohn?

A

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.

15
Q

VT

A

Tidal volume

the volume of air inhaled during normal breathing

At rest, usually about 500 ml

16
Q

Residual volume

A

The volume remaining in the lungs after a maximal exhalation

17
Q

Expiratory reserve volume

A

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

18
Q

Inspiratory reserve volume

A

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

19
Q

Total lung capacity

A

The volume of gas in the lungs after maximal inspiration.

approx 7 L in healthy adults

TLC = IC + FRC

20
Q

Vital capacity

A

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

Normal value about 5 L

VC =IRV + TV + ERV

21
Q

Functional residual capacity

A

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

FRC = ERV + RV

22
Q

IC

A

inspiratory capacity

IRV + TV

23
Q

How do you determine FRC with helium?

A

With Helium:

FRC = Vs x (C1/C2-1)

C1/2 = concentration 1/2

Vs = volume of spirometer

24
Q

How do you determine FRC with whole body plethysmography?

A
  • 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
25
Q

Ventilation definition

A

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.

26
Q

VE

A

VE = minute ventilation, the total volume exhaled per minute

VE = R x VT

27
Q

VA

A

Alveolar ventilation- ventilation of the respiratory zone of the lungs

VA = R (VT-VD)

VD = dead space ventilation

28
Q

Why is VA less than VE?

A

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

29
Q

How is deadspace determined?

A

VD= VT x (PaCO2-PECO2)/(PaCO2)

PECO2 = expired CO2 at the mouth

30
Q

Does PACO2 equal PaCO2?

A

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

31
Q

What is the respiratory exchange quotient?

A

0.8

For every O2 inhaled, 0.8 CO2 are exhaled

32
Q

How do you calculate PO2 of room air at sea level?

A

PO2 = 0.21 x 760 mmHg = 160 mmHg

33
Q

How do you calculate PIO2 in the trachea?

PIO2 = inspired gas

A

PIO2 = 0.21 x (760-47) mmHg = 150 mmHg

34
Q

How do you calculate the composition of alveolar gas?

A

PAO2 = (PIO2 - PACO2)/R

R = Respiratory exchange quotient = 0.8

35
Q

What is the Alveolar-Arterial gradient?

normal value?

A

PAO2-PaO2 = Alveolar-Arterial gradient

normally 5-10 mmHg

36
Q

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

A

the gradient would be bigger than 10 mmHg

37
Q

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

A

both the PAO2 and the PaO2 would go down equally with a ventilation problem. The gradient would stay the same.

38
Q
A