Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

CPR1 Exam 2 > 2- Alveolar Gas Exchange > Flashcards

2- Alveolar Gas Exchange Flashcards

1
Q

The point of the lungs is to bring ________ and ________ together. The purpose of the _________ is what brings these two things together.

A

Ventilation (air)
Perfusion (blood)
Alveolus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What are the airways not designed to participate in gas exchange?

A

Anatomic Dead Space

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What’s happening physiologically in the conducting airways?

A

Air Flow

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

When air flows through a tube, the airway _________ makes airflow more difficult.

A

Resistance

***This is the control of bronchiole diameter

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

If airway resistance is (HIGH/LOW), airflow slows down and takes more muscle effort to produce. If airway resistance is (HIGH/LOW), airflow is fast and easy.

A

High

Low

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What controls the airway resistance? Think of the equation for resistance.

A

R = 8nL/rˆ4

n = viscosity (for air, this won't change much)
L = length of tube
r = radius of tube ***Main factor
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

The control of the bronchiole diameter (airway resistance) is courtesy of the ________ ________ in the airway walls.

A

Smooth Muscle

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Why do we want to change the airway resistance?

A

– I want to send the air in my lungs to the ‘right’ places. For right now, that means alveoli that have a good blood supply.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

This is the volume of air reaching the alveoli.

A

Alveolar Ventilation

***The amount of air reaching the alveoli every minute is the Minute Alveolar Ventilation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What is the equation for Minute Alveolar Ventilation?

A

VA(dot) = VA x F

***4 L/min is average value!

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Perfusion (Q) is from the _______ _______ and is 5 L blood/min.

A

Right Ventricle

***Won’t have to calculate this!

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What is the equation for the diffusion rate in ml/min of a gas?

A

J = [ (S.A.) x D x (P1-P2) ] / Distance

J = diffusion rate in ml/min 
D = diffusion coefficient for each gas
(P1-P2) = pressure gradient across alveolar membrane 
S.A. = surface area available for diffusion 
Distance = diffusion distance (thickness of alveolar barrier)

***This equation is solved for each gas individually! DO NOT HAVE TO SOLVE!

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

So how much gas is exchanged every minute? Meaning, what is J (diffusion rate in ml/min)? These values under normal resting conditions are…

A

250 mL O2 are exchanged every minute.

200 mL CO2 are exchanged every minute.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

The diffusion of each gas (O2 and CO2) is __________ of one another.

A

Independent

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What factors in the diffusion rate equation (J) depend directly on the structure of the alveolus?

A

S.A.

Distance

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

S.A. in the diffusion rate equation (J) is the surface area available for diffusion. It corresponds to the number of ________ in the lungs.

A

Alveoli

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

As surface area increases, J will (INCREASE/DECREASE) and vice versa.

A

Increase

***This is why patients with emphysema (COPD) have a hard time getting sufficient oxygen into their system. They lost alveoli so their surface area is reduced, thus reducing their diffusion rate.

18
Q

Distance in the equation refers to the diffusion distance (thickness of alveolar barrier). What all is included as part of the distance?

A
    • Fluid layer
    • Alveolar epithelium
    • Interstitial space
    • Blood vessel wall
19
Q

As distance increases, J will (INCREASE/DECREASE) and vice versa.

A

Decrease

20
Q

The deposition of collagen within the interstitial spaces increases the diffusion distance, which results in a (INCREASE/DECREASE) of the diffusion of the gases across the barrier.

A

Decrease

***This occurs in people with Interstitial Lung Disease

21
Q

D is the diffusion coefficient for each gas. D depends on what?

A
    • The solubility of the gas in water (in your body)
  • **O2 less soluble in water than CO2
    • The molecular weight of the gas.
  • **CO2 weighs more than O2
22
Q

The solubility of CO2 more than counters the difference in molecular weight, so DCO2 is _______ the DO2.

A

20x

***Means CO2 is way more soluble than O2, so CO2 will cross even if O2 is having a hard time!

23
Q

If the numbers are positive or negative for the pressure gradient, what does that mean?

A 
Positive = moving in 
Negative = moving out
24
Q

An RBC spends about _______ seconds in a pulmonary capillary (under resting conditions).

A

0.75

25
Q

O2 requires about _______ seconds in a pulmonary capillary to reach equilibrium. O2 diffuses very easily but because of this, it depends on how much blood is present to take it away. This is called ________ ________.

A

0.25
Perfusion Limited

***Because RBC spend 0.75 seconds in the capillary, it allows for plenty of time for oxygen to diffuse!

26
Q

During heavy exercise, a RBC spends _______ seconds in the pulmonary capillary. Due to this, it takes a lot of time for oxygen to diffuse because the RBCs don’t spend enough time in the capillary. This is called ________ ________. Someone with lung disease will first notice problems during exertion because of this.

A

0.25

Diffusion Limited

27
Q

In an normal person DLO2 is the diffusion capacity of the lung for oxygen, which is about _______ mL O2/min/mmHg at rest.

A

21

28
Q

To measure the DLO2 we use ________ _______ because it binds to Hb so avidly that it doesn’t dissolve in the plasma. Its arterial pressure is 0 mmHg because it’s all bound to Hb.

A

Carbon Monoxide (CO)

29
Q

To measure the DLCO we have the patient inhale a single breath of air with a small percentage of CO added. We can now calculate the DLO2 by the equation…

A

DLO2 = 1.23 x DLCO

30
Q

An RBC spends about 0.75 seconds in a pulmonary capillary (under resting conditions). So we have a huge ‘safety’ margin of time before the RBC leaves the capillary. Therefore, a person has to have extensive lung disease before they have problems with _______ retention.

A

CO2

31
Q

CO2 equilibrium in the pulmonary capillary is almost immediate. This makes the DLCO2 at rest to be estimated at _______ mL/CO2/min/mmHg.

A

400

***Way bigger than DLO2, which was 21!

32
Q

T/F. Changes in PaO2 will occur earlier in the disease process due to limitations in oxygen diffusion.

A

True

33
Q

What is LaPlace’s Law?

A

Pressure (inside alveolus) = 2T/r

T = tension
r = radius
34
Q

In a large alveolus, the radius is large. How does this affect the LaPlace’s Law equation?

A

Increased radius would cause decreased pressure. So the pressure within the large alveolus is relatively low.

35
Q

In a small alveolus, the radius is small. How does this affect the LaPlace’s Law equation?

A

Decreased radius would cause increased pressure. So the pressure within the small alveolus is relatively high.

36
Q

Surface tension would not be problem if all alveoli were the same size, but in real life they are not. They also share airways. Because little alveoli and big alveoli can share airways, what can happen (in a diseased person)?

A

Air will move from high to low pressure in the little to big alveoli. This causes the little alveoli to collapse into the big alveoli. This causes the big alveoli to get even bigger, which is bad for surface area because there is less available space for diffusion.

***Remember, this does NOT happen because of surfactant!

37
Q

________ changes the surface tension. It reduces surface tension in the smallest alveoli more than in larger alveoli.

A

Surfactant

38
Q

What produces surfactant?

A

Type II Pneumocytes

39
Q

What is the main phospholipid that surfactant is composed of?

A

Dipalmitoylphosphatidylcholine

40
Q

Surfactant has multiple proteins, but the main one we’re worried about is _______ because it is particularly important to the function. Without it, the lung couldn’t inflate after a deep breath out.

A

SPB

41
Q

Surfactant is stored in the intracellular ________ _______ and secreted into the alveolus.

A

Lamellar bodies

42
Q

Surfactant decreases surface tension in proportion to the radius. This reduces the pressure in the small alveoli. This reduced pressure now means there is NO pressure gradient for air to move down, so there is no ________.

A

Collapse

CPR1 Exam 2 (27 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions