CO2 transport

Question 1

CO2 is transport from tissue to lungs in how many and which forms (and proportions)

Answer 1

3 forms

1. HCO3- (90%)
2. Carbaminohemoglobin (HbCO2) (5%)
3. Dissolved CO2 (5%)

Question 2

Carbaminohemoglobin (HbCO2) - structure

Answer 2

CO2 bound to Hb at N-terminus (NOT HEME)

Question 3

CO2 binding on hemoglobin favors …. form of hemoglobin

Answer 3

taut (O2 unloaded)

Question 4

CO2 transportation - what is happening in the lungs

Answer 4

oxygenation of Hb promotes dissociation of H+. This shift equilibrium (CO2 + H20 - H2O2 - H+ + HCO3-) toward CO2 formation. Therefore, CO2 is released from RBCs (Haldane effect)

Question 5

CO2 transportation - what is happening in the peripheral tissues

Answer 5

increased H+ from tissue metabolism shifts curve to right, unloading O2 (Bohr effect)

Question 6

RBC - membrane antiporter

Answer 6

CL-/HCO3-

Question 7

Bohr effect vs Haldone effect according to location

Answer 7

Bohr effect–> peripheral tissue

Haldane effect –> lungs

Question 8

Haldane effect

Answer 8

oxygenation of the blood causes CO2 releasing from RBCs

Question 9

lung Response to high altitude - adaption

Answer 9

1. increased ventilation 2. increased erytrhopoietin

3. increased 2,3-BPG 4. Cellular changes 5. Right ventricular hypertrophy 6. increased renal exertion of HCO3-

Question 10

lung Response to high altitude - PCO2? (mechanism)

Answer 10

decreased

because of the increased ventilation

Question 11

lung Response to high altitude - cellular change

Answer 11

increases mitochondria

Question 12

lung Response to high altitude - ventilation (chronic)

Answer 12

chronic increased in ventilation

Question 13

lung Response to high altitude - reflex

Answer 13

decreased atmospheric P02 –> decreased Pa02 –> increased ventilation –> decreased in PaCO2

Question 14

lung Response to high altitude - heart structure changes? (mechanism)

Answer 14

chronic hypoxic pulmonary vasoconstriction result s in

RIGHT VENTRICULAR HYPERTROPHY

Question 15

lung Response to high altitude - Hb modification

Answer 15

increased in 2,3-BPG –> binds to Hd so that

Question 16

lung Response to high altitude - renal response

Answer 16

1. increased erythropoietin –> increased hematocrit and Hb (chronic hypoxia)
2. increased renal excertion of HCO3- to compensate for respiratory alkalosis

Question 17

lung response to high altitude - compensation of respiratory alkalosis

Answer 17

increased renal excretion of HCO3

Question 18

Response to high altitude - renal excretion of HCO3 can augment with

Answer 18

acetazolamide

Question 19

Lung response to exercise

Answer 19

1. increased CO2 production 2. increased O2 consumption 3. increased ventilation rate (to meet O2 demand)
2. V/Q ratio from apex to base more uniform
3. increased pulmonary flow (increased CO)
4. decreased ph in strenuous (lactic acidosis)

Question 20

Lung response to exercise - O2 and CO2 in arterial and venous blood

Answer 20

1. no change of PaO2 and PaCO2

2. increased in venous CO2 and decreased in venous O2 content

Question 21

Lung response to exercise - V/Q

Answer 21

more uniform from apex to base

Question 22

Lung response to exercise - cardiac output

Answer 22

increased