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EXCI 357 Pulmonary Physiology > 5. Transport of Oxygen in Blood and Body Fluids > Flashcards

5. Transport of Oxygen in Blood and Body Fluids Flashcards

1
Q

How does blood get transported from pulmanry blood to peripheral tissues?

A

Mainly via Hb binding

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2
Q

Presence of Hb in RBC allows blood to transport ______x as much O2 as could be transported in dissolved state

A

30-100 times

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3
Q

In tissue cells, CO2 is formed as a ______. Enters tissue capillaries and gets transported __________

A

Waste Product

Back to the lungs

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4
Q

Like O2, CO2 combines to chemical substances in blood to _________ transport 15 to 20-fold

A

Increase

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5
Q

Does the increase in cardiac out put during exercise have an effect on the time hat blood remains in pulmonary capillaries? If so is this a problem related to DLO2?

A

yes, time that blood remains in pulmonary capillaries can decrease by half.

This is not a problem because, at rest, blood becomes almost saturated with O2 by the time has passed 1/3 of the capillary. So during exercise, even if exposure time is reduced, blood can still become fully oxygenated

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6
Q

A. Order theses from most pressure to lease PaO2, PO2 in, tissues, PAO2
B. How does this help with O2 transport?

A

A. PAO2&raquo_space; PaO2&raquo_space; PO2 in tissues

B. Allows O2 to diffuse from alveoli to blood to tissues

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7
Q

A. Order theses from most pressure to lease PaCO2, PCO2 in, tissues, PACO2

B. How does this help CO2 transport?

A

A. PCO2 in tissues&raquo_space; PaCO2&raquo_space; PACO2

B. Allows CO2 to diffuse from tissues to capillary blood to alveoli

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8
Q

Transport of O2 and CO2 by blood depends on? ( 2)

A

Diffusion &

Blood flow

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9
Q

What is the PO2 at the arterial end and venous end of pul. arteriole? (value)

A
  • > 40mm Hg

- > 104 mm Hg

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10
Q

What is PAO2? (value)

A

104 mmHg ( = venous end of pul. arteriole )

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11
Q

Does PaO2 remain the same value as PAO2 after leaving the arteriole system? Why or why not?

A

No goes down to 95mm Hg as it mixes with pulmonary shunted bloods ( blood that fed the lungs with O2 rich blood and is now O2 deficient)

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12
Q

When arterial blood reaches peripheral tissues, PO2 is still ____ mmHg, while PO2 in interstitial fluid surrounding tissue cells is only ____mmHg. This causes O2 to ______________; So blood leaving capillaries have a PO2 of?

A

~95 mmHg
40
Causes O2 to diffuse rapidly from capillary blood into tissues.
~ 40 mmHg

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13
Q

PO2 inside the cell is equal to?

A

23 mmHg

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14
Q

Increased blood flow affects interstitial fluid PO2 how?

A

Increases interstitial PO2 due to there being more O2 transportation = Increased PO2 in interstitial fluid.

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15
Q

Increased tissue metabolic rate affects interstitial fluid PO2 how?

A

Decreased interstitial fluid PO2, due to Increased O2 consumption by the cells ( O2 goes from ints fluid -> cells)

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16
Q

True or false. Increased tissue metabolic rate decreases intracellular PO2

A

False. O2 is continuously being used by tissue cells, so intracellular PO2, or PO2 (cell), remains relatively low

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17
Q

This pressure difference causes O2 to diffuse from extracellular fluid into tissue cell? What is it’s avg value?

A

The average oxygen pressure difference across the tissue cell membrane.
ΔPO2 = 17 mmHg
( ΔPO2 = PO2 (int) - PO2 (cell) = 40 - 23 )

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18
Q

In normal resting condition, only _____ mmHg of intracellular O2 pressure is required for tissue cell to fully support the oxygen supply for its metabolic process. Average intracellular PO2 = ____ mmHg thus provides a _____ safety factor

A

1 to 3 mmHg

avg = 23mmHg

large

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19
Q

Why does a PO2 = 23 in the cells mmHg thus provides a large safety factor.

A

In normal resting condition, only 1 to 3 mmHg of intracellular O2 pressure is required for tissue cell to fully support the oxygen supply for its metabolic process.

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20
Q

How many ways of O2 transport are there? And what are?

A

Two:

~97% is carried in chemical combination with hemoglobin in RBC

~3% is carried in dissolved state in water of plasma and blood cells

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21
Q

O2 combined ______and _______ to heme portion of Hb. Why is this a good thing?

A

loosely & reversibly
When PO2 is high (e.g. pulmonary capillaries), O2 binds with Hb
When PO2 is low (e.g. tissue capillaries), O2 is released from Hb

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22
Q

When PO2 is _____, O2 binds with Hb

When PO2 is _____ , O2 is released from Hb

A

high (e.g. pulmonary capillaries)

low (e.g. tissue capillaries)

23
Q

what is the relationship between PO2 levels and Hemoglobin O2.
Is it linear?

A

Increased PO2 = Increased hemoglobin saturation

No. More of an s shape and whereby PO2 has less of an effect on Hemaglobin saturation percentage after 60 mmHg

24
Q

Blood of normal person contains ___g of Hb/100 ml blood. Each gram of Hb can bind with a maximum ___ml of O2. Therefore, maximum amount of O2 that can be carried by 100 ml of blood is ____

A

~15g
1.34

20 ml O2 /100 ml blood
( -. 1.34 (ml O2/g Hb) x 15 (g Hb/100 ml blood)

25
Q

This value is obtained if Hb is 100% saturated with O2, and is known as _____________

A

20 ml O2/100 ml blood

20 volumes percent

26
Q

In terms of O2 release from Hb as systemic arterial blood flows through tissues.

  • PO2 of blood leaving lungs (entering systemic arteries)?
  • % of Hb saturated with O2?
  • Volumes percent? What does this value mean?
A

95 mmHg
% of Hb saturated with O2 = 97%

19.4 ( Aka CaCO2)

It means that ~19.4 ml of O2 carried by each 100 ml of blood in systemic arterial blood (CaO2)

27
Q

Oxygen unloading at the tissue level (capillary content):

  • PO2 of blood at venous end of tissue capillary ?
  • Volumes percent? What does this value mean?
A

40 mmHg

14.4

It means that after passing through tissue capillaries, amount of O2 carried by blood in veins (CvO2) reduces to 14.4 ml of O2 for each 100 ml of blood (on average)

28
Q

Arterio-venous (A-V) O2 difference (tissue level). What does this represent?

A

CaO2 – CvO2

  1. 4 – 14.4 = 5 ml O2/100 ml blood
    - > Tissues use 5ml O2/ 100 ml of blood supplied ( 20% at rest)
29
Q

Rapid use of O2 by tissue cells can cause PO2 in interstitial fluid to fall from normal of _______ to as low as _______? At this low PO2, only_____ O2 remains bound with Hb in each 100 ml blood

A

40 mmHg
15 mmHg
4.4 ml O2/ 100 ml blood exiting the venous end of the tiss. cap.

30
Q

Arterio-venous (A-V) O2 difference during strenous exercise?

A

15 ml O2/100 ml blood ( = 19.4 - 4.4: A-V )

31
Q

During strenuous exercise____ times as much O2 as normal is extracted in each volume of blood that passes through tissues

A

3x as much O2

32
Q

What is the O2 Utilization coefficient: At rest vs during strenous exercise?

A

At rest: 25% (5 ml O2/100 ml blood over possible max of 20)

During strenuous exercise: >75% (15/20)

33
Q

Which one of these factors shift the O2 Dissociation Curve to right or left?

i. increased ph
ii. Increase CO2
iii. increased temp
iv. increased DPG

A

All of them shift the curve to the right

34
Q

Increase in H+ (acidosis) shifts the O2 dissociation curve to the?

A

right

35
Q

Decrease of pH from 7.4 (normal level) to 7.2 leads to ________(% inc or dec) of hemoglobin saturation with O2

A

~15% decrease

36
Q

Increase of CO2 in blood or increase of PCO2 (hypercapnia) leads to shift of O2 dissociation curve to the _____?

A

Right

37
Q

Bohr effect: _______shift of O2 dissociation curve caused by increase of _______ and decrease in ____ in the blood. This ______ release of O2 from blood in tissues

A

Rightward
CO2 (or PCO2)
pH of blood
Enhances

38
Q

True or false. The Borh a effect has an opposite on the O2 dissiocation Curve in the lung vs in blood?

A

True. Curve is shifted to the left, so enhances oxygenation of blood in lungs

39
Q

Increase in core or tissue temperature leads to a______ shift of oxygen dissociation curve.

A

RIghtwards

40
Q

True or false?A decrease in tissue temperature results in Decrease hemoglobin saturation with O2

A

False. Conversely, a decrease in tissue temperature results in increased hemoglobin saturation with O2

41
Q

What is DPG?

A

2,3 diphosphoglycerate (DPG) is a metabolic end-product of glycolysis in the red blood cell

42
Q

True or false. Increase in DPG in blood shifts O2 dissociation curve toward the right

A

True

43
Q

True or false. Heat accelerates glycolysis (formation of ATP from glucose), therefore increases DPG in blood. Which leads to a leftwards shift in the O2
Dissociation Curve.

A

False. eat accelerates glycolysis (formation of ATP from glucose), therefore increases DPG in blood. Which would actually lead to a RIGHTWARD shift in the O2
Dissociation Curve

44
Q

What is the difference between fetal hemoglobin and regular hemoglobin?

A

Fetal hemoglobin has strong affinity for O2 and therefore, shifts O2 dissociation curve to the left

45
Q

In hypoxia condition (lasting longer than a _______), lack of O2 in tissue promotes production of ______ in blood. Which shifts O2 dissociation curve to ______ . Unltimately resulting in _______ hemoglobin saturation with O2

A

few hours
DPG
the right
decreased

46
Q

Hypoxia causes O2 to be released to tissues at PO2 levels as much as _______ times (Higher or lower?). Why is this beneficial?

A

10 times higher

It can become an important adaptive mechanism to hypoxia, e.g. if poor tissue blood flow

47
Q

Does exericse produce a massive leftwards or rightwards shift in the O2 dissociation curve?

A 
Rightwards. 
Due to:
Increased
- release of CO2
- Temp (2-3 degrees C)
- pH in muscle    capillaries

–> Ultimately, Forces O2 to be released from blood Hb to muscles

48
Q

True or false. O2 availability is the main limiting factor of O2 usage by the cells?

A

False. Cells only need PO2 of 1 mmHg for normal intracellular chemical reactions to occur

49
Q

Main limiting factor of what controls rate of O2 usage by cells under normal operating conditions is concentration of ______?

A

Main limiting factor is concentration of adenosine diphosphate (ADP) in cells

50
Q

Rate at which ADP is formed from ATP (i.e. rate of energy expenditure within cell) is what controls rate of _______under normal operating conditions

A

O2 usage by cells

51
Q

If ATP/ADP > 1. Tissue will or will not consume additional quantities of O2 for producing ATP? Why?

A

Will not

Why: Plenty of ATP is available for energy use by the cell

52
Q

If ATP/ADP < 1. Tissue will or will not consume additional quantities of O2 for producing ATP? Why?

A

Will!

Why: Relatively more ADP than ATP is present so more O2 will be consumed to raise the ATP level

53
Q

Factors that affect oxygen consumption at the tissue level. List the transport factors and the metabolic factors.

A 
Transport factors:
Blood flow
Perfusion pressure
Capillary resistance
Hemoglobin

Metabolic factors:
Tissue activity
State of conditioning
Number and size of mitochondria

EXCI 357 Pulmonary Physiology (7 decks)

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