Respiratory System 4 Flashcards

1
Q

what are the two ways that oxygen is transported in the blood

A

dissolved in blood plasma and chemically bound to hemoglobin

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2
Q

define hemoglobin

A

protein contained in the red blood cells

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3
Q

how many molecules of oxygen can a molecule of hemoglobin carry

A

4, one on each heme

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4
Q

what is a fully saturated hemoglobin

A

all four heme groups bound to oxygen

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5
Q

what is a partially saturated hemoglobin

A

1,2, or 3 oxygen molecules are bound to a hemoglobin molecule

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6
Q

explain loading of O2 onto hemoglobin

A

occurs in the alveolar capillaries
oxygen binds to heme to form oxyhemoglobin (HbO2)

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7
Q

explain unloading of O2 from hemoglobin

A

occurs in the tissues
oxygens unbinds from hemoglobin to form deoxyhemoglobin and oxygen

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8
Q

what determines the direction of the hemoglobin reaction

A

partial pressure of oxygen in the blood and the affinity of hemoglobin and O2

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9
Q

define the cooperative binding effect

A

each O2 that binds causes a conformational change in hemoglobin making it easier for next O2 to bind
produces a sigmoidal (S-shaped) curve

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10
Q

explain the oxygen-hemoglobin saturation curve

A

initial curve is steep because of cooperative binding effect
as PO2 goes up, saturation goes up (happens in the alveoli)
as PO2 goes down, saturation goes down because it is being offloaded to go to the tissues

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11
Q

define oxygen reserve

A

oxygen bound to hemoglobin after passing through the systemic circulation

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12
Q

what are the 5 factors that affect hemoglobin’s binding and release of oxygen

A

PO2
pH
concentration of CO2
temperature
2,3-biphosphogylcerate (2,3-DPG)

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13
Q

explain how PO2 affects hemoglobin’s binding and release of oxygen

A

as PO2 goes up, we have more binding of O2 to hemoglobin
as PO2 goes down, we have more releasing of O2 from hemoglobin

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14
Q

explain how pH affects hemoglobin’s binding and release of oxygen

A

as pH goes down, H+ ions increase which decrease the affinity of oxygen to bind to hemoglobin
as pH goes up, H+ ions decrease which promotes the binding of oxygen to hemoglobin

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15
Q

explain how concentration of CO2 affects hemoglobin’s binding and release of oxygen

A

CO2 concentrations and saturation are inversely related
when CO2 concentrations increase, O2 is released from hemoglobin
when CO2 concentrations decrease, O2 is bound to hemoglobin

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16
Q

explain how temperature affects hemoglobin’s binding and release of oxygen

A

temperature and saturation are inversely related
as temperature increases, hemoglobin will release oxygen
as temperature decreases, hemoglobin will bind to oxygen

17
Q

explain how 2,3-biphosphoglycerate (2,3-DPG) affects hemoglobin’s binding and release of oxygen

A

inversely related
as 2,3-DPG levels goes up, oxygen will be released from hemoglobin
as 2,3-DPG levels go down, oxygen will bind to hemoglobin

18
Q

what does a right shift in a oxygen-hemoglobin saturation curve mean and what can cause it

A

Bohr effect: means that the % of oxygen saturation goes down
PO2 down
pH down; H+ up
concentration of CO2 up
temperature up
2,3-DGP up

19
Q

what does a left shift in a oxygen-hemoglobin saturation curve mean and what can cause it

A

Haldane effect: increase oxygen binding to hemoglobin
PO2 up
pH up; H+ down
concentration of CO2 down
temperature down
2,3-DGP down

20
Q

how does altitude affect oxygen-hemoglobin saturation

A

as we go up in altitude, PO2 in atmosphere goes down which means our oxygen saturation also goes down

21
Q

how does a pulse oximeter measure oxygen in the blood

A

goes on finger
special light passes through your skin into your blood
sensor measures the amount of light and % of red blood cells that are full of oxygen
determines amount of deoxyhemoglobin vs oxyhemoglobin
usually around 95%

22
Q

what are the three ways in which carbon dioxide is transported

A

as CO2 dissolved in plasma
attached to amine group of the globin portion of hemoglobin
as bicarbonate dissolved in plasma

23
Q

what is the equation for CO2 attaching to amine group of hemoglobin

A

CO2 + Hb <–> HbCO2 (carbaminohemoglobin)

24
Q

what are the two ways in which CO2 can be transported as bicarbonate dissolved in plasma

A

systemic capillaries and pulmonary capillaries

25
Q

explain how CO2 is transported as a bicarbonate dissolved in the blood plasma at the systemic capillaries

A

CO2 diffuses into red blood cell and combines with H2O to form carbonic acid - catalyzed by carbonic anhydrase
carbonic acid dissociates into bicarbonate and hydrogen ion
bicarbonate diffuses into plasma and chloride moves into red blood cell (chloride shift)

26
Q

explain how CO2 is transported as a bicarbonate dissolved in the blood plasma at the pulmonary capillaries

A

bicarbonate moves into the red blood cell, chloride moves out
bicarbonate combines with H+ to form carbonic acid
carbonic acid dissociates into CO2 and water (catalyzed by carbonic anhydrase)
CO2 diffuses out of red blood cell and into alveoli to be breathed out