Respiratory physiology 5 Flashcards

1
Q

Calculate the patient’s arterial oxygen content from the data set:
Hgb 9 g/dL
HR: 100 bpm
Stroke volume: 70 mL
SaO2: 90%
PaO2: 60 mmHg
a. 10.641 mL O2/dL
b. 11.034 mL O2/dL
c. 11.894 mL O2/dL
d. 12.002 mL O2/dL

A

b. 11.034 mL O2/dL
CaO2= (1.34 x Hgb x SaO2) + (PaO2 x 0.003)

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2
Q

Oxygen content is a measure of how much

A

oxygen is present in 1 deciliter (100 mL) of blood

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3
Q

What is the oxygen content equation?

A

CaO2= (1.34 x Hgb x SaO2) + (PaO2 x 0.003)

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4
Q

Oxygen delivery tells us

A

how fast a quantity of O2 is delivered to the tissues

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5
Q

What is the oxygen delivery equation?

A

DO2= CaO2 x cardiac output x 10

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6
Q

Oxygen consumption is the

A

difference between the amount of O2 that leaves the lungs and the amount of O2 that returns to the luns

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7
Q

What is the oxygen consumption equation?

A

VO2= cardiac output x (CaO2-CvO2) x 10

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8
Q

After oxygen diffuses through the alveolar capillary membrane, it is transported by the blood in 2 ways:

A
  1. reversibly binds with hemoglobin (97%)
  2. dissolves in the plasma (3%)
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9
Q

Each gram of hemoglobin molecule can carry a theoretical maximum of

A

1.39 mL of molecular oxygen

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10
Q

VO2 equals

A

3.5 mL/kg/min

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11
Q

Vo2 is about ___________ in a 70 kg male

A

250 mL/min.

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12
Q

P50 is reduced by: (select 3) a. hgb f
b. hyperthermia
c. hypocarbia
d. increased 2,3 DPG
e. acidosis
f. carboxyhemoglobin

A

a. hgb F
c. hypocarbia
f. carboxyhemoglobin

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13
Q

P50 is the

A

PaO2 where hemoglobin is 50% saturated with oxygen

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14
Q

The oxyhemoglobin dissociation curve tells us the

A

tendency of hemoglobin to bind oxygen

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15
Q

A right-shifted oxyhemoglobin curve means

A

right= release
hemoglobin has a lower affinity for oxygen

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16
Q

A left-sided oxyhemoglobin curve means

A

left= love
hemoglobin has a higher affinity for oxygen

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17
Q

A lower P50 reflects

A

a left shift (left= love)

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18
Q

A higher P50 reflects a

A

right shift (right= release)

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19
Q

A left shift (decreased P50) is caused by

A

alkalosis, decreased temperature
decreased 2,3-DPG

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20
Q

A right shift (increased P50) is caused by

A

acidosis
increased temperature
increased 2,3-DPG

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21
Q

What hemoglobin species can cause a left shift?

A

fetal hemoglobin
methemoglobin
carboxyhemoglobin

22
Q

The Bohr effect says that an increased partial pressure of Co2 and decreased pH cause

A

hemoglobin to release O2

23
Q

Above a PaO2 of 100 mmHg,

A

hemoglobin is fully saturated with oxygen; increasing the FiO2 further will increase the amount of O2 dissolved in the blood

24
Q

Increased hydrogen leads to

A

left shift of the oxyhemoglobin curve

25
Q

2,3 DPG is produced during

A

RBC glycolysis (Rapoport-Leubering pathway)

26
Q

___________ increases 2,3 DPG production

A

hypoxia; this increases O2 offloading

27
Q

2,3 DPG is an important compensation mechanism during

A

chronic anemia

28
Q

In banked blood, the concentration of 2,3 DPG

A

falls- shifts the oxyhemoglobin dissociation curve to the left

29
Q

Identify the statement that BEST describes aerobic metabolism.
a. NADH is the final electron acceptor during electron transport
b. 1 molecule of glucose converts to 38 molecules ATP
c. Pyruvic acid is converted to lactate
d. Electron transport occurs in the cytoplasm

A

b. 1 molecule of glucose converts to 38 molecules ATP

30
Q

_____________ is the energy currency in the body

A

Adenosine triphosphate (ATP)

31
Q

________ is the primary substrate used for ATP synthesis.

A

Glucose

32
Q

What are the 3 key processes involved in aerobic metabolism:

A
  1. glycolysis= net gain of 2 ATP
  2. Krebs cycle= net gain of 2 ATP
  3. oxidative phosphorylation= net gain of 34 ATP
33
Q

The body’s enzymes tend not to function properly in

A

an acidic environment

34
Q

In the absence of oxygen (anaerobic metabolism), pyruvate is converted to

A

lactic acid- this causes lactic acidosis

35
Q

ATP cannot be

A

stored so the supply must continuously be replenished

36
Q

Energy sources include

A

proteins, carbohydrates and fats

37
Q

Energy usage is from

A

active transport
synthetic function
muscle contraction
cell division and growth

38
Q

The more glucose molecules that go through glycolysis, the more ___________ is produced

A

2,3 DPG b/c the Rapoport-Luebering pathway occurs halfway through glycolysis

39
Q

The Krebs cycle takes place in the

A

matrix of the mitochondria

40
Q

The primary goal of the Krebs cycle is to

A

produce a large quantity of H+ ions in the form of NADH- these are used in electron transport

41
Q

What is the primary goal of electron transport?

A

to produce a lot of ATP (energy)

42
Q

What is the primary goal of glycolysis?

A

to convert 1 glucose to 2 pyruvic acid molecules

43
Q

Importation of which ion maintains electroneutrality during the Hamburger shift?

A

Chloride

44
Q

The primary by-product of aerobic metabolism is

A

carbon dioxide

45
Q

The 3 primary ways that CO2 is transported (buffered) in the blood:

A
  1. as bicarbonate (70%)
  2. bound to hemoglobin (23%)
  3. dissolved in the plasma (7%)
46
Q

Carbonic anhydrase is an enzyme that facilitates the formation of

A

carbonic acid (H2CO3) from H2O & CO2

47
Q

To maintain electroneutrality, for every molecule of HCO3- that leaves the erythrocyte, one ________________ is transported in

A

Cl- ion- this is known as the chloride or Hamburger shift

48
Q

A more acidic environment enhances O2 ______________ & ________________ CO2 loading into the blood

A

enhance O2 offloading from hemoglobin (Bohr effect) & increases CO2 loading into the blood (Haldane effect)

49
Q

What is the carbonic anhydrase equation?

A

H2O+ CO2 <–> H2CO3 <–> H+ + HCO3-

50
Q

In the lungs, the chloride shift operates

A

in reverse as CO2 is excreted from the body

51
Q

Dissolved CO2 has a solubility coefficient of

A

0.067 mL/dL/mmHg

52
Q

Solubility is a function of

A

Henry’s law