Brainscape's Knowledge GenomeTM

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


See full index

respiratory > 4 – Pulmonary Circulation > Flashcards

4 – Pulmonary Circulation Flashcards

1
Q

What is the pressure in systemic capillaries?

A

-high
>80-120mmHg

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

What is the pressure in the pulmonary capillaries?

A

-low
>8-25mmHg

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

How much of total blood volume do the pulmonary capillaries account for?

A

~10%

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

Pulmonary capillaries characteristics:

A

-thinner wall, less smooth muscle=lower pressure
-low resistance
*highly distensible and compressible (7x more compliant than systemic) to accommodate changes in R heart output
-extensive branching

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

Extensive branching of pulmonary capillaries facilitate:

A

-gas exchange

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

What do pulmonary capillaries respond to?

A

-contract and relax in response to neural or humoral factors to alter resistance

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What happens to pulmonary capillaries during exercise?

A

-vascular resistance decreases (pressure increases)
-70mL at rest to 250mL to maximize gas exchange

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

The lung receives blood from 2 separate sources, what are they?

A

-bronchial circulation (part of systemic)
-pulmonary circulation

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

Bronchial circulation provides:

A

-nourishment
-arterial perfusion from trachea to terminal bronchioles

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

Bronchial circulation arises:

A

-variably
>aorta or intercostal arteries

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

Bronchial circulation pressure and blood:

A

-systemic system=high pressure
-receives 1% of cardiac output
-1/3 venous blood returns to R atrium via azygos vein
-2/3 venous blood goes to pulmonary vein and L atrium (mixes with O2 rich blood)

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

Pulmonary circulation receives:

A

-total (100%) output from R ventricle for gas exchange
>reoxygenated and release CO2
*low pressure, high volume

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

Pulmonary circulation perfusion to:

A

-structures distal of terminal bronchioles
>nutrients from mixed venous blood

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

To facilitate gas exchange, we need:

A

-presence of oxygen in alveoli
-flow of blood to pulmonary capillaries

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

Optimal gas exchange formula:

A

-alveolar ventilation (V) (oxygen) divided by pulmonary perfusion/flow (Q) (blood)
=1
*normal is 0.8
*inadequate V or Q leads to VQ mismatch

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

Blood flow distribution (Q) can be influenced by:

A

-gravity
>exhibits a vertical gradient dependent on the position of the animal
*volume to pressure to flow is mostly higher in caudal/ventral vs. cranial/dorsal

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

Exception in horses: gravity on Q

A

-flow is higher in dorsal region vs. ventral
-large vertical lung height and dorsal distance relative to the heart requires higher pulmonary arterial pressure to drive blood flow
>minimizes the effect of gravity
>pulmonary arterial pressure in horse is higher than dogs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Intense exercise (ex. race horse) leads to:

A

-huge increase in pulmonary pressure (>60mmHg)
>almost same pressure of systemic system
>*risk of capillary rupture (exercise-induced pulmonary hemorrhage)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Exercise-induced pulmonary hemorrhage:

A

-blood will enter alveoli
>get blood coming out of nose

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Gravity on alveolar size (V):

A

-transpulmonary pressure drives distension
>greater the pressure=greater the pull=larger the alveoli=greater V
*alveolar size at cranial/dorsal half is larger than the caudal/ventral half

21
Q

Alveolar pressure:

A

-external pressure on capillary

22
Q

Respiratory zones:

A

-3 conceptual zones
>boundaries between zones are dependent on physiological conditions
-pulmonary capillaries and alveoli are both distensible and compressible

23
Q

Zone 1 pressure:

A

-alveolar P > alveolar P > venous P

24
Q

Zone 1:

A

-large alveoli (large transpulmonary pressure)
-reduced blood flow
-does not normally exist in healthy lungs (physiological dead space)
>could theoretically occur near apex/dorsal region

25
Q

Zone 1: V/Q

A

-high ventilation (V)
-low blood flow (Q)
*V/Q is very high (mismatch)
*wasted ventilation

26
Q

Zone 1: wasted ventilation

A

-lots of gas (V) but not enough blood flow (Q) to facilitate gas exchange

27
Q

Physiological examples of zone 1:

A

-pulmonary embolism
>blood clot in R. side of heart
-late-stage COPD involving capillary damage
-emphysema
>lung is so large it can’t recoil=restricts blood flow

28
Q

Zone 2 pressure:

A

-arterial P > alveolar P > venous P

29
Q

Zone 2:

A

-alveoli is open and filled with air
-sufficient systole pressure forces deoxygenated blood into capillaries towards alveoli to facilitate gas exchange
-appropriate amount of oxygen and blood flow
*best functioning zone of the lung

30
Q

Why is zone 2 the best functioning zone of the lung?

A

-blood flow (Q) closely matches with ventilation (V)
>~1
>physiological average is 4/5=0.8
*optimal gas exchange

31
Q

Optimal gas exchange is a balance of:

A

-alveolar ventilation and pulmonary blood flow

32
Q

Zone 3 pressure:

A

-arterial P > venous P > alveolar P

33
Q

Zone 3:

A

-alveoli is small (low transpulmonary pressure)
-high blood flow
-partially functioning zone:
>could theoretically occur near caudal/ventral area

34
Q

Zone 3: V/Q

A

-high perfusion (Q)
-low ventilation (V)
*V/Q is very small (mismatch)
*wasted perfusion

35
Q

Zone 3: wasted perfusion

A

-lots of blood flow (Q), but not enough gas (V) to facilitate gas exchange

36
Q

Physiological examples of zone 3;

A

-pulmonary hypertension (higher arterial P)
-bronchoconstriction/atelectasis (low alveolar pressure)

37
Q

Examples of modifying factors on V/Q zones: zone 1

A

-low BP=increase zone 1
Ex. hemorrhage: reduce arterial P

38
Q

Examples of modifying factors on V/Q zones: zone 3

A

-high BP=increase zone 3
Ex. pulmonary hypertension: increase arterial P

39
Q

Examples of modifying factors on V/Q zones: forceful inspiration

A

-shift zone 3 to zone 2 by expanding the alveoli (increase alveolar P)
-will also have a small shift from zone 2 to zone 1

40
Q

Examples of modifying factors on V/Q zones: exercise

A

-increase in cardiac output=increase arterial P
>zone 1 to zone 2
-coupled with forceful respiration (alveolar P)
>zone 3 to zone 2
*maximal zone 2 to support aerobic demand

41
Q

Another example of something that can modify V/Q capacity:

A

-change in anatomical position

42
Q

What do you need to re-oxygenate the blood?

A

-oxygen in alveoli AND
-adequate blood flow past alveoli

43
Q

Pathological states will cause abnormal shifts into zone 1 or zone 3:

A

-dead space
-shunt
*V/Q mismatch leads to hypoxemia (low O2 in systemic blood)

44
Q

Dead space

A

-zone 1: V»Q, V/Q&raquo_space;1
-presence of air without blood
-causes are vascular (ex. blood clot, embolism)

45
Q

Shunt:

A

-zone 3: V«Q, V/Q«1
-presence of blood without air
-causes are due to airway (ex. bronchoconstriction, atelectasis)

46
Q

Blocked/collapsed alveoli (ex. pneumonia); pneumonic region:

A

-receives no ventilation
-blood flow through that region does not pick up any O2
-mixes with oxygenated blood from healthy alveoli
>reduces pressure of O2 returning to the heart

47
Q

Result of reduced pressure of O2 returning to the heart:

A

-de-O2 blood leaving from the R ventricle returns as still poorly oxygenated blood at the L. ventricle ->hypoxemia

48
Q

Oxygen supplementation and hypoxemia:

A

-does NOT substantially improve hypoxemia
>does not overcome the obstructed alveoli (fluid-filled)

respiratory (9 decks)

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