Resp 4 Flashcards

1
Q

Gases, just like ions and water, move

according to the principles of

A

diffusion

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2
Q

he partial pressures of the gases

ONLY include the gases that are

A

dissolved in the plasma

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3
Q

If cells utilize more oxygen than
normal, the gradient —-
which — flow of oxygen
from the blood to the tissues

A

increases

increases

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4
Q

Tissue PO2 is a function of: (2)

A
(1) The rate of O2 transport 
to the tissues in blood 
(blood flow)
(2) The rate at which the 
tissues use O2.
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5
Q

Increased blood flow and/or
increased metabolism will
result in

A

more O2 delivery to

the tissues.

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6
Q
Without Hemoglobin, CO 
would need to be --- L/min 
to transport sufficient oxygen 
to meet the needs of the 
tissues at rest.
A

83.3

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7
Q

–% of total oxygen content is
dissolved in plasma (PaO2 =
100 mmHg)

A

2

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8
Q

–% of O2 reversibly binds to

hemoglobin inside of the RBC

A

98

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9
Q

98% of O2 reversibly binds to
hemoglobin inside of the RBC
-does not contribute to

A

partial

pressure

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10
Q

Hemoglobin A (α2b2):

A

4 subunits
each of which each binds 1 O2
molecule.

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11
Q

Iron must be in — state

to bind O2

A

ferrous (Fe2+)

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12
Q

The amount of oxygen
bound to Hb
depends on: (2)

A
  1. Plasma PO2
  2. Number of binding
    sites in RBCs –
    depends on the Hb
    amount per RBC.
    (normally each
    RBC contains ~1
    million Hb
    molecules)
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13
Q

CaO2 =

A

ml of O2 carried by oxyhemoglobin plus ml of O2

carried dissolved in plasma

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14
Q

skipped
equation
CaO2 =

A

SaO2 (Hb x 1.34) + 0.003 (PaO2)

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15
Q

SaO2 is the

A

% saturation of hemoglobin

– Average 97%

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16
Q

Hb represents

A

g of hemoglobin/100 ml blood

– Average is 15 g Hb/100 ml blood

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17
Q

PaO2 is the

A

partial pressure of oxygen in arterial blood

– Average is 95 mmHg

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18
Q

Average CaO2 is ~

A

19.782 ml O2/ 100 ml blood

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19
Q
Reduction in the 
amount of hemoglobin 
in the blood 
significantly reduces 
the
A

blood oxygen

content.

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20
Q

2,3-BPG binds to

A
Beta 
subunits of deoxy HB 
and decreases its O2 
affinity. It causes more 
oxygen unloading. 
Normal Venous PvO2 Normal Arterial PaO2
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21
Q

At a high PO2,
hemoglobin’s
affinity for O2 is

A

highest.

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22
Q

At a high PO2,
hemoglobin’s
affinity for O2 is
highest.

A

POSITIVE COOPERATIVITY.

23
Q

The lower the
PO2, the more
likely

A

O2 will
dissociate from
hemoglobin

24
Q

Oxyhemoglobin Dissociation Curve

Shifts to the RIGHT is called the

A

bohr effect

25
Q

Oxyhemoglobin Dissociation Curve
Shifts to the RIGHT
indicates:

A

DECREASED affinity
between hemoglobin
and oxygen

26
Q

Oxyhemoglobin Dissociation Curve
Shifts to the RIGHT
in this instance,

A

oxygen
is MORE likely to
dissociate from
Hemoglobin.

27
Q

RBCs contain 2,3-bisphosphoglycerate
– a metabolic intermediate. Levels of
2,3-BPG increase with (4)

A

exercise,
hypoxia from high altitude, pregnancy
and chronic lung disease.

28
Q

Oxyhemoglobin Dissociation Curve
Shifts to the RIGHT
Helps match

A

O2 delivery to
O2 demand, advantageous
since O2 can be released at
selective tissues.

29
Q

Oxyhemoglobin Dissociation Curve Shifts to
the LEFT
indicates

A

an INCREASED affinity between oxygen and

hemoglobin

30
Q

Oxyhemoglobin Dissociation Curve Shifts to
the LEFT
In this instance,

A

oxygen is LESS likely to dissociate

from hemoglobin.

31
Q

Oxyhemoglobin Dissociation Curve Shifts to
the LEFT
caused by (4)

A

– Decreased PCO2
– Increased pH (ex. 7.6)
– Decreased temperature
– Decreased 2,3-BPG

32
Q

Carbon Monoxide has a —x greater affinity for

Hemoglobin than Oxygen.

A

250X

33
Q

Only small amounts of CO can be lethal

A

• CO bound to hemoglobin increases
Hb’s affinity for O2 (a left-ward shift in
curve)

34
Q

Even though CaO2 may be greatly

reduced,

A

PaO2 of blood may be normal.

35
Q

Carbon Monoxide-Hemoglobin Curve

Treatment: (2)

A
  • Pure oxygen

* 5% CO2

36
Q

Presentation of CO Poisoning:

A

“Common in smoke inhalation,
enclosed exposure to automobile exhaust, or in the wintertime with
home furnaces. Patients present with cherry red skin (classic), flu-
like symptoms, headache, and neurologic symptoms.”

37
Q

Variants of Hemoglobin (3)

A
Methemoglobin  
Hemoglobin F (Fetal Hemoglobin)
Hemoglobin S (Sickle Cell)
38
Q

Methemoglobin (2)

A

– Heme with Fe3+ does not bind O2 as readily
(reduced affinity) & also causes any heme groups in
the same Hb molecule with heme in the Fe2+ state to
have have higher affinity for bound O2  net effect
is reduced O2 delivery to the tissues
– Can occur due to G6PDH deficiency or upon
exposure to some local anesthetics (prilocaine and
benzocaine).

39
Q

Hemoglobin F (Fetal Hemoglobin) (2)

A

– α2gamma2 (no β chains)
– Higher affinity for oxygen than HbA because it
doesn’t contain the Beta chain that binds to 2, 3-
BPG.

40
Q

Hemoglobin S (Sickle Cell) (3)

A

– Normal α units, abnormal beta units (due to one amino
acid change)
– When deoxygenated, RBCs
form sickle shapes, obstructing small vessels
– O2 has lower affinity for HbS than Hb A

41
Q

About — mL of carbon dioxide is
produced by the tissue metabolism each
minute in a resting 70-kg person and must
be carried by the — blood to the lung
for removal from the body.

A

200 to 250

venous

42
Q

At a cardiac
output of 5 L/min, each 100 mL of blood
passing through the lungs must therefore
unload — mL of carbon dioxide

A

4 to 5

43
Q

Carbon Dioxide Transport in the Blood

Transported as: (3)

A
  1. Dissolved CO2
  2. Carbamino-hemoglobin
    (CO2Hgb)
  3. Bicarbonate (HCO3-)
44
Q

Carbon Dioxide Transport in the Blood

Volume of transport is

A

~4 ml CO2/ 100 ml blood.

45
Q

Carbon Dioxide Transport Mechanisms (3)

A
  1. Dissolved CO2 ~7%
  2. Carbaminohemoglobin (& Carbamino Compounds) ~23%
  3. Bicarbonate ~70%
46
Q

Dissolved CO2 ~7%

A

– PCO2 is 40mmHg in arterial blood, 46 mmHg in venous bl

47
Q

Carbaminohemoglobin (& Carbamino Compounds) ~23% (2)

A

– CO2 forms a loose, reversible bond with hemoglobin (on terminal
amine groups)
– Slowest of the reactions

48
Q

Bicarbonate ~70% FAST! (2)

A

– In RBCs, carbonic anhydrase rapidly forms carbonic acid from H2O
and CO2, which in turn dissociates to H+ and HCO3-

– H+ combines with hemoglobin for buffering and HCO3- moves into
plasma in exchange for Cl- (via band 3 protein)

49
Q

Carbon Dioxide Transport Mechanisms: Systemic
Capillaries

If there were no 
carbonic 
anhydrase, 
PaCO2 would 
equal
A

80 mmHg
(compared to the
normal of 45
mmHg).

50
Q

Carbon Dioxide Transport Mechanisms: Systemic
Capillaries

Haldane
Effect:

A
Deoxygenated 
Hb promotes 
increased 
binding of 
CO2 to Hb.
51
Q

Carbon Dioxide Transport Mechanisms:
Pulmonary Capillaries

Note the reverse 
direction of the 
transport by band 
three protein, which 
leads to (2)
A
an increase 
in intracellular HCO3- 
and production of 
CO2 via carbonic 
anhydrase.
52
Q

Carbon Dioxide Transport Mechanisms:
Pulmonary Capillaries

Haldane
Effect:

A

Oxygenated
Hb promotes
dissociation of
CO2 from Hb.

53
Q

Carbon Dioxide Transport Mechanisms:
Pulmonary Capillaries

Movement of CO2 into the
alveolus will — PaCO2

A

decrease