Lecture 3- Gas transport

Question 1

less than …% of the oxygen in the blood is dissolved and this amount represents what is available to diffuse

Answer 1

2%

Question 2

98% of O2 in the blood is …

Answer 2

bound to hgb

Question 3

hgb is a … pigment found in …. erythrocytes

Answer 3

respiratory

mammalian

Question 4

hgb is the predominant protein i nerythrocytes, estimates of …. million hb molecules per cell

Answer 4

250-280 million

Question 5

hgb is a …. molecule meaning it has … protein subunits, each has a …. group that includes 1 iron atom that can …. bind O2

Answer 5

tetrameric

4

heme

reversibly

Question 6

O2 carrying capacity of hgb

Answer 6

0-4

Question 7

the plateau region of the o2-hgb dissociation curve is the …. phase

Answer 7

loading

Question 8

the steep region of the o2-hgb dissociation curve is the … phase

Answer 8

unloading

Question 9

as PO2 decreases in the blood, hgb’s affinity for O2 rapidly …

Answer 9

decreases

Question 10

P50 is the PO2 at which half of the hgb is …

Answer 10

saturated

Question 11

PO2 is a measure of …. O2 and ONLY … O2 can diffuse into tissues

Answer 11

dissolved

Question 12

it is critical to maintain a pool of dissolved O2 to supply….

Answer 12

mitochondrial demand

Question 13

there will be an increase in hgb’s affinity for oxygen if there is a shift of the curve to the …. and hgb is saturated at a lower PO2

Answer 13

left

Question 14

There will be a decrease in hgb’s affinity for oxygen if there is a shift of the curve to the …. and hgb is less saturated for a given PO2

Answer 14

right

Question 15

what shifts the curve to the right

Answer 15

increased temp
increased acidity
added DPG

Question 16

what shifts the curve to the left

Answer 16

decreased temo
decreased acidity
no DPG

Question 17

is arterial PO2 cahnged in anemia or CO poisoning?

Answer 17

no, but total O2 content is reduced

Question 18

hgb affinity for CO is …. than for O2

Answer 18

200 fold greater

Question 19

CO2 is transported in 3 forms

Answer 19

dissolved (7%)
bound to hgb (23%)
as HCO3 (70%)

Question 20

CO2 binds to globin portion of hgb to form ….

Answer 20

carbaminohemoglobin

Question 21

CO replaces O2 on hgb competing for binding sites on hgb and forms …

Answer 21

carboxyhemoglobin

Question 22

if PCO2 is increased, then hgb’s affinity for CO2…

Answer 22

increases

Question 23

if PO2 decreases, hgb’s affinity for CO2…

Answer 23

increases

Question 24

the CA reaction … plasma

Answer 24

acidifies

Question 25

... is the enzyme that catalyzes the formation of carbonic acid

Answer 25

carbonic anhydrase

Question 26

Carbonic anhydrase is found in ... not ....

Answer 26

erythrocytes plasma

Question 27

erythrocytes have a ... transporter that moves... into the plasma

Answer 27

HCO3/Cl HCO3

Question 28

H+ binds to .... residues on hgb and hgb buffers most of the H+ produced by CA

Answer 28

histidine

Question 29

oxyhgb affinity for H+ is ...

Answer 29

low

Question 30

deoxyhgb affinity for H+ is ...

Answer 30

high

Question 31

in the tissues, hgb picks up ... and minimizes effect of ... on pH

Answer 31

H+ HCO3

Question 32

hypoventilation leads to

Answer 32

respiratory acidosis

Question 33

hyperventilation leads to

Answer 33

respiratory alkalosis

Question 34

hypoventilation, respiratory acidosis is when theres a .... in PCO2 and H+

Answer 34

increase

Question 35

hyperventilation, respiratory alkalosis is when theres a ... in PCO2 and H+

Answer 35

decrease

Question 36

the oxy-hgb curve describes the effect of ... on hgb saturation

Answer 36

PO2

Question 37

P50 is the PO2 at which .... of hgb is saturated

Answer 37

1/2

Question 38

2,3 DPG is a product of ... in erythrocytes that enhances offloading/dissociation of O2 by allosteric modulation

Answer 38

glycolysis

Question 39

breath holding is extreme

Answer 39

hypoventilation