Respiration 3

Question 1

how much O2 is dissolved in the blood

Answer 1

less than 2 %

Question 2

how do we get a sufficient amount of oxygen to support basal metabolism

Answer 2

98% of our oxygen comes from oxygen that is bound to hemoglobin (Hb)

Question 3

what form must oxygen be in to be used by tissues of the body

Answer 3

dissolved oxygen

Question 4

is the dissolved oxygen component alone sufficient to support basal metabolism

Answer 4

no

need Hb bound oxygen

Question 5

what is Hb

Answer 5

a respiratory pigment

protein carrier for oxygen

Question 6

what is the structure of Hb

Answer 6

tetrameric molecule: 4 subunits each with a heme group that includes 1 iron atom that reversible binds O2

Question 7

maximum amount of O2 that can bind to one Hb molecule

Answer 7

4 O2 molecules

Question 8

what are the possible oxygen states for each Hb

Answer 8

can carry 0-4 O2 molecules

Question 9

what cell contains Hb predominantly

Answer 9

erythrocytes

Question 10

when is oxygen carrying capacity of Hb full

Answer 10

when all 4 O2 molecules are bound

Question 11

what influences total O2 available in the blood

Answer 11

amount of hemoglobin

partial pressure of O2

Question 12

what is cooperative binding

Answer 12

this is how O2 binds to Hb

as each O2 molecule binds to Hb it increases Hb affinity for more O2 until reaches saturation

Question 13

how does the binding of O2 increase the affinity of more O2 to Hb

Answer 13

the binding of O2 causes a conformational change

Question 14

what type of curve represents the cooperative binding of Hb

Answer 14

sigmoid curve

Question 15

what are the other substances that can affect the Hb’s affinity for O2

Answer 15

H+, CO2, CO, DPG

Question 16

how does PO2 affect Hb saturation if it is increase

Answer 16

increases saturation of Hb

more O2 available to bind to Hb

Question 17

loading phase

Answer 17

above 60 mmHg PO2

Hb will pick up O2 but not as readily give it up (plateau region)

Question 18

unloading phase

Answer 18

less than 60 mmHg PO2

rapid decrease in Hb saturation as PO2 decreases (steep region)

no enough dissolved O2 so Hb will want to give off O2 so it can be used by tissues

Question 19

what is P50 on the sigmoid curve

Answer 19

the partial pressure of O2 at which half of the hemoglobin are saturated

Question 20

why is dissolved O2 never over 2 %

Answer 20

because of poor solubility of O2

Question 21

what happens to PO2 as if flows from the air to the mitochondria of the cells

Answer 21

PO2 will decrease

Question 22

what happens to O2 on Hb when PO2 is decreased

Answer 22

more O2 will be released as “dissolve oxygen” to be taken up by the tissues

Question 23

what measure ONLY dissolved O2

Answer 23

PO2

Question 24

what is the main purpose of Hb

Answer 24

increases the total oxygen at any PO2 but must be released in order to diffuse

also storage of O2

Question 25

pathway of O2 from alveoli to pulmonary blood

Answer 25

diffuse across respiratory surface into plasma-->diffuse across plasma membrane of erythrocyte to bind to Hb

Question 26

how is the PO2 gradient conserved in transport of O2 from alveoli to pulmonary blood

Answer 26

uptake of oxygen by Hb

Question 27

what happens when PO2 drops | in terms of Hb and bound oxygen

Answer 27

Hb will release O2 and O2 will diffuse out of the erythrocyte

Question 28

what is the pathway of O2 from the diffusing out of erythrocyte to the mitochondria of tissue cells

Answer 28

diffuses out of erythrocyte-->interstitial fluid-->tissue cells-->mitochondria

Question 29

what maintains the pressure gradient for O2 from the erythrocyte to the mitochondria

Answer 29

the oxygen is consumed in the mitochondria so O2 stays at a very low pressure in the mitochondria keeping the pressure gradient

Question 30

how much free oxygen is delivered to the tissues in tissue capillaries (from when the pressure is 100-40 mmHg)

Answer 30

about 20% of oxygen

Question 31

what factors decrease Hb affinity

Answer 31

1. increase temperature 2. increased CO2 3. increased H+ 4. increased 2,3 diphosphoglycerate (DPG)

Question 32

explain role of temperature on Hb affinity

Answer 32

increased temperature decreases affinity of oxygen to Hb ex: drowing in cold water is better because increases affinity of oxygen to Hb and have more stored; can be released when tissues need it

Question 33

explain role of CO2 on Hb affinity

Answer 33

CO2 binds to a non competitive site on Hb which decreases affinity for O2 (allosteric modulation)

Question 34

explain role of H+ on Hb affinity

Answer 34

H+ binds to histamine residues on Hb which decreases affinity to O2 (allosteric modulation)

Question 35

explain role of 2,3 DPG on Hb affinity

Answer 35

RBC produce DPG when PO2 drops decreases affinity of O2 to Hb so more dissolved O2 is readily available for tissues

Question 36

what happens during exercise to increase free O2 for tissues

Answer 36

increase temperature increase DPG increase acidity

Question 37

What are the normal arterial values for Hb and oxygen in the blood

Answer 37

15 gm if Hb and 20 ml of oxygen in 100 ml of blood

Question 38

What happens to the amount of Hb in the blood in anemia

Answer 38

Fewer erythrocytes so less Hb per ml of blood

Question 39

In anemia what is not changed and what is reduced in terms of Hb saturation po2 and total oxygen content

Answer 39

Po2=same Hb saturation= same Total oxygen content= reduced

Question 40

Is the relationship between CO and O2 competitive or non competitive

Answer 40

Competitive; fight to bind to the same Fe site on hemoglobin

Question 41

What is the product called when CO binds to Hb

Answer 41

Carboxyhemoglobin

Question 42

If o2 and CO are floating around, which one will more likely bind to the Fe site on Hb

Answer 42

CO; Hb has 200 fold more affinity to CO than O2; can displace O2

Question 43

In CO poisoning what happens to pO2 or Hb concentration and total oxygen content

Answer 43

Po2 does not Change Hb concentration does not change Total oxygen content is reduced

Question 44

Three ways to treat CO poisoning

Answer 44

1. Remove source of CO 2. Ventilate with pure O2 3. Increase atmospheric pressure so PO2 will increase in the lung (breathe in)