Resp 3 gas exchanges

Question 1

how many branches are in the conducting zone and respiratory zone

Answer 1

1-16

17-23

Question 2

how does gas movement occur ?

Answer 2

by convection

Question 3

ficks law in the lungs ?

Answer 3

it is the gas exhange across the blood gas barrier in the alveolus occurs through diffusion

Question 4

how is oxygen transported through blood ?

Answer 4

in 2 forms:

1. physically- plasma soluble O2 (2%)
   
   • less soluble than CO2
   • 2. Chemically- O2 bound to hemoglobin (98%)
   • rapid and reversibe interactio- allows O2 off loading to tissues
   • Hb+ O2 <——>HBO2
     3.

Question 5

how is saturation calculated ?

Answer 5

oxyhemoglobin / O2 carrying capacity of Hb

Question 6

what does arterial plateau ensure ?

Answer 6

it ensures that maximal HbO2 saturation even if alveolar PO2 is below the normal oxygen tension.

Question 7

what alters the dissocaition curv e of oxyheomglobin/

Answer 7

high altitiudes- decreased Hb-O2 affinity and raised O2 offloading to tissues (right shift)

Fetal Hb- increased Hb-O2 and reduced O2 Offloading to tissues

Question 8

what is the bohr effect

Answer 8

is the increase in C02 and decrease in pH leads to a lower affinity for Oxygen to bind to heamoglobin.

Question 9

what is the structure of Heamoglobin ?

Answer 9

2 alpha and 2 beta units with 4 Iron groups.

Question 10

what are the 3 things that affact the alpha and beta subunits of heamoglobin to stop O2 binding

Answer 10

CO2, pH, 2,3 bisphosphoglycerate

Question 11

how does pH affect the oxygen binding

Answer 11

Decrease in pH leads to Acidosis= which favours the alpha and beta subnuit interactio and reduced the O2 to heam binding.

Question 12

what are the 2 ways increased blood pCO2 releases (lowers affinity) O2 from Hb?

Answer 12

1. production of carbonic acid in red cells- carbonic anhydrase
   
   • CO2 +H2O–> H2CO3 <–> HCO3- + H+
2. carbamate reactio at the N terminal Amino Groups on the alpha subunit
   
   • CO2 + R-NH2 <—-> -R-NH-COO- + H+

Question 13

how many ways is CO2 transported ?

Answer 13

3 ways 2 are physical and 1 is chemical

1. Physical- Plasma Soluble
   
   1. solbule CO2 (5%)
   2. Bicarbonate Ion (90%)
2. Chemically- Carbamino Haemoglobin

Question 14

exchange of what molecule leads to maintiance of gradiaent ?

Answer 14

HCO3- out of the cell and Cl- into the cell. this keeps up the gradient and therefore CO2 can go into the cell and Buffers the PH of the plasma to 7.4

Question 15

what is the halden Effect ?

Answer 15

low tissue O2 favorurs CO2 carriage by blood

Question 16

how does CO2 and O2 exchange at the tissue

Answer 16

CO2 dissolves into plasma along a partial pressure gradient

low tissue O2 favours CO2 carriage by blood

carbamate reaction reduces HbO2 affinity

Carbonic anhydrase reaction generates carbonic acid which protonates. HCO3- leaves the cell and maintains inwards Co2 gradient

Increased H+ reduces HbO2 affinity by the intreaction of Alpha and beta subunits.

Question 17

describe the dissolving of O2 and CO2 and the alveolus surface.

Answer 17

O2 dissolves into plasma/ red blood cells via partial pressure gradient

high affintiy of Hb for O2 reverses Hb carbamation and protonation raising availabilty of high affinty Hb

Co2 diffuses into the alveolus along the pressure gradient. High PO2 dereases CO2 Affinity for Hb

Movement of CO2 out of the red cell increases HC03- and Cl- moves out

Proton release from Hb and Drives carbonic anhydrase reaction in reverse maintaing outward Co2 gradient and Loweing plasma bicarbonate.

Question 18

what does hypoxia do ?

Answer 18

constricts pulmonary arteries to increase pulmonary transit time of blood

Question 19

what is the difference between perfusion and ventilation

Answer 19

ventilation is the movement of air in and out of the alveoli whereas perfusion is the flow of blood to the capillaries