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Pathophysiology > Module 3: Respiration > Flashcards

Module 3: Respiration Flashcards

(58 cards)

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1
Q

What is gas exchange driven by?

A

Pressure gradients at both PULMONARY capillaries and SYSTEMIC capillaries

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2
Q

Alveoli PO2 = ____ mmHg

A

103

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3
Q

Describe the PO2 levels of pulmonary capillaries as they return from the tissues and when they leave to go to the rest of the body

A

PO2 of blood returning from tissues = 40 mmHg

PO2 of blood leaving pulmonary capillaries is saturated with O2 so it goes up to 100 mmHg

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4
Q

Alveoli PCO2 = _____ mmHg

A

40

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5
Q

Describe the PCO2 levels of pulmonary capillaries as they return from the tissues and when they leave to go to the rest of the body

A

PCO2 of blood returning from tissues = 45 mmHg

PCO2 of blood leaving pulmonary capillaries has REDUCED it’s CO2 so that it it is 40 mmHg

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6
Q

The tissue PO2 can be as low as ___ mmHg (depending on _____)

A

20 mmHg

metabolism demand

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7
Q

Tissue capillary PO2 of blood entering tissues is:

A

90-100 mmHg

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8
Q

Blood leaving the tissue capillaries that has already delivered its O2 is approx: ____ mmHg

A

40

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9
Q

Tissue PCO2 = ____ mmHg (depending on ____)

A

46 mmHg

metabolism demand

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10
Q

Tissue capillary PCO2 is ____ mmHg

A

40 mmHg

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11
Q

Blood leaving the tissue capillaries that has increased it’s CO2 now is approx. ____ mmHg

A

45 mmHg

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12
Q

Percentage of Oxygen in atmospheric air:

Calculate it’s partial pressure

A

21%

PO2 = 760 x 21% = 159 mmHg

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13
Q

Percentage of CO2 in atmospheric air

Calculate it’s partial pressure

A

.03%

PCO2 = 760 x .03% = .22 mmHg

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14
Q

What is the percentage of O2 and CO2 in alveolar pressures?

A 
O2 = 14.5% (760-47)(14.5%)
CO2 = 5.5%
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15
Q

What is an average resting Cardiac Output (CO)

A

5 L/min

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16
Q

What is the average exercise cardiac output (CO)?

A

up to 25 L/min

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17
Q

Which is more compliant with alveoli ventilation: the base or the apex of the lungs?

Why?

A

The base because the alveoli are smaller and have a reduced surface tension and therefore easier to inflate

The apex inflates during extremes of ventilation (WOB/accessory muscles, etc)

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18
Q

Pulmonary circulation and function are ____ dependent.

A

Gravity

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19
Q

What happens if alveolar gas pressure exceeds capillary pressure?

A

Perfusion slows or stops

The capillary “collapses” or “is compressed” thus blood flow stops

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20
Q

Where are the three zones of ventilation and perfusion located in the lung?

A

Zone I: At apex (small area)

Zone II: Area above left atria

Zone III: Base of the lung

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21
Q

Zone I: describe relationship between pressures and what happens to perfusion

A

Alveolar pressure > arterial capillary pressure > venous capillary pressure

Perfusion: is STOPPED by the alveolar pressure

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22
Q

Zone II: relationship between pressures and what happens to perfusion

A

Arterial capillary pressure > alveolar pressure > venous capillary pressure

Perfusion: is SLOWED DOWN by alveolar pressure

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23
Q

Zone III: relationship between pressures and what happens to perfusion:

A

Arterial capillary pressure > venous capillary pressure > alveolar pressure

Perfusion: is NOT EFFECTED by the alveolar pressure

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24
Q

V/Q ratio

Study These Flashcards
A

Compares the amount of air that enters the alveoli each minute with the amount of blood that travels through pulmonary capillaries each minute (Cardiac Output)

AKA: Alveolar Ventilation / Cardiac Output

25
V/Q ratio between base and apex of lung:
Apex: Ventilation exceeds perfusion so a very small portion of lung Base: Perfusion exceeds ventilation
26
Clinical V/Q
The sum of V/Q from all zones Normal = 4.2L / 5.0L = 0.8 (ventilation slightly less than perfusion)
27
How do you calculate alveolar ventilation?
(Tidal Volume - Dead Space) x RR (500ml - 150 ml) x 12 = 4.2 L
28
What happens to V/Q during moderate exercise?
V/Q remains at 0.8 Both ventilation and respiration increase proportionately
29
What happens to V/Q during intense exercise?
V/Q increase 5/1 This means ventilation increases much more than perfusion
30
Are lungs a limiting factor in exercise?
NO!!
31
If blood flow is obstructed then what happens to V/Q? Name a clinical example
V/Q INCREASES infinitely ex: Pulmonary Embolism
32
If ventilation is obstructed then what happens to V/Q? Name a clinical example
V/Q DECREASES ex: COPD
33
What drives oxygen transport across alveolar capillary membranes?
The pressure gradient
34
How long (in seconds) does it take RBC to travel through pulmonary capillaries
0.75 seconds
35
How long (in seconds) does it take to bind O2 to hemoglobin?
0.25 seconds
36
SaO2 =
saturation of oxygen in arterial blood
37
100% saturation of oxygen in the blood =
transport a max of 20 ml of O2 per 100 ml of blood
38
______ partial pressure of arterial O2 (paO2) will ______ Hb affinity for O2
INCREASED partial pressure of arterial O2 (paO2) will INCREASE Hb affinity for O2
39
______ partial pressure of arterial O2 (paO2) will ______ Hb affinity for O2
DECREASED partial pressure of arterial O2 (paO2) will DECREASE Hb affinity for O2
40
What does the "Oxyhemoglobin dissociation curve" demonstrate?
Saturation amounts at different pressures
41
Describe the "flat" top portion of the oxyhemoglobin dissociation curve:
Represents a "buffer" zone 60-100 mmHg Increased O2 binding to Hb is maintained at these pressures
42
Describe the "steep" portion of the oxyhemoglobin dissociation curve:
This portion progressively favors O2 to be released into systemic tissue O2 dissociation from Hb is increasing as these pressures decrease
43
What are the 4 factors that alter the oxyhemoglobin dissociation curve?
1. Body temperature 2. 2,3 DPG levels 3. pH (H+) levels 4. CO2 levels
44
What does 2,3 DPG do?
DPG alters the hemoglobin to decrease O2 affinity
45
"Right Shift" of oxyhemoglobin dissociation curve:
Occurs when: Inc. CO2, Inc. H+, DEC pH levels, Inc. temp, Inc. BPG Results in a decreased affinity for Hb and O2
46
"Left Shift" of oxyhemoglobin dissociation curve:
Occurs when: H+ dec, CO2 dec, Temp dec, pH INC., dec. DPG Results in increased affinity for Hb and O2
47
Acidosis
Elevated H+ levels
48
Hypercapnia
Elevated CO2 levels
49
Alkalosis
Decreased H+ levels
50
Hypocapnia
Decreased CO2 levels
51
Bohr Effect
Presence of CO2 will decrease O2 and Hb affinity i.e., Increased CO2 levels will alter affinity Typically occurs in tissue
52
Haldane Effect
Presense of O2 will decrease CO2 and Hb affinity i.e., increased O2 levels will alter affinity Typically occurs in lungs
53
If PaO2 is 100 mmHg then the blood is _____ saturated. Is this in a healthy or unhealthy individual?
98% healthy
54
If PaO2 is 60mmHg then the blood is _____ saturated. Is this in healthy or unhealthy individual?
90% Beginning of "flat" portion of curve...starting to be unhealthy
55
If PaO2 is 40 mmHg then the blood is ____ saturated Is this in healthy or unhealthy individual?
75% Typical of blood leaving exercising muscle
56
Is CO2 more soluble or less soluble than O2?
CO2 is 20 times more soluble than O2 and diffuses much quicker than O2 and thus doesn't require a large pressure gradient
57
What are the 3 "forms" of carbon dioxide transport?
1. CO2 dissolves into plasma 2. CO2 binds to hemoglobin 3. CO2 forms bicarbonate (HCO3-)
58
What are the percentages associated with each form of CO2 transport?
1. CO2 dissolving into plasma: 5-10% 2. CO2 binding to hemoglobin: 5-30% 3. CO2 forms bicarbonate: 60-90%

Pathophysiology (12 decks)

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