Respiratory Physiology II Ch 11

Question 1

The respiratory Zone

Answer 1

diffusion of 02 into the blood and co2 out of the blood occurs here (alveoli where epithelia cells contact external mediums)

Question 2

The Respiratory membrane

Answer 2

extremally thin barrier in the Respiratory zone which separates alveolar air from blood in the capillaries

Question 3

What is the driving force for the diffusion of gases

Answer 3

Partial pressures( gas diffusion occurs down the gas partial pressure gradient )

Question 4

The Partial pressure of gases in the fluid phase

Answer 4

The partial pressure of as which is dissolved in a liquid is equal to the partial pressure of that gas in the air phase with which the fluid is a eq w

( the capacity of water to hold 02 is much lower then that of air )

Question 5

gases diffuse according to what

Answer 5

Their partial pressures not their concentrations

Question 6

Most efficient Gas exchanger

Answer 6

Least is found in mammals most is found in fish

and blood PO2> expired PO2 in efficient system

The increase respiratory surface provides the most efficient system

Question 7

PP of O2 does what during each step of the O2 transport pathway

Answer 7

Decreases

Question 8

Oxygen transport Pathway

Answer 8

Ventilation–> diffusion across r pathway surface–> Circulation–> cellular utilization

Question 9

Alveolar air and blood leaving lungs PP

Answer 9

very similar PP

Question 10

PP in blood leaving lungs and entering systemic capillary beds

Answer 10

they are the same

Question 11

PP in cells vs blood

Answer 11

They are very different

Question 12

PP in venous blood leaving the systemic capillaries and entering the pulmonary capillary beds

Answer 12

They are the same

Question 13

Haemoglobin

Answer 13

Each composed of 4 subunits each of which consists of a heme ring which binds 1 O2 molecules and and polypeptide which binds CO2 and other accessory’s.

Question 14

transport of O2 via haemoglobin

Answer 14

as blood passes through the tissues 02 diffuses into the tissues and reduces the Blood P02 which promotes the release of 02 thus formation of deoxyhemoglobin thus making Hb desaturated in the tissues

Question 15

Positive Allosteric modulator for haemoglobins affinity for 02

Answer 15

O2

Question 16

negative allosteric modulator in hemoglobin for H and CO2

Answer 16

O2

Question 17

How does O2 binding promote further O2 binding

Answer 17

when O2 binds it removes salt bridges and favors protein conformation in the R sate

Question 18

Flat region of the Hb-oxygen eq curve

Answer 18

Provides safety margin for 02 loading if arterial P02 falls ( this region is highly saturated with hemoglobin)

Question 19

The Knee and steep part of the Hb-oxygen curve

Answer 19

Located to enhance O2 unloading during exercise, this area is associated with small decrease in the venous Po2(mild hemoglobin saturation)

Question 20

The bohr shift on the Hb-oxygen eq curve

Answer 20

Improves O2 unloading during exercise
increase in PvCO2 shifts curve right and decrease in VpH also shifts curve right

Question 21

Increase in temperature and Hb-equilibrium curve

Answer 21

Increase in blood temp shifts the curve right enhancing the unloading of O2

Question 22

Increase in RBC phospahte does what to the Hb-oxygen eq curve

Answer 22

Shifts it right

Question 23

Transport of CO2 in the blood

Answer 23

10% is physically dissolved
30% binds to Hb to form carbamino-CO2
60% is transported as HCO3 ion and dissolved in the plasma

Question 24

role of Carbonic Anhydrase

Answer 24

to catalyze reactions

Question 25

Driving pressure for diffusion of CO2 in blood

Answer 25

CO2 tissues > CO2 capillaries(right shift)
CO2 in blood> CO2 in alveoli(left shift)

Question 26

The Haldane effect

Answer 26

Mirror image of the Bohr effect

Question 27

Transport of gases in the blood as blood passes through the pulmonary capillaries

Answer 27

Increasing PO2, Decreasing PCO2 and [H], O2 eq shifts lefts which facilates O2 loading and CO2 unloading

Question 28

Transport of gases in the blood as Blood passes through systemic capillaries

Answer 28

Decreasing PO2, Increasing PCO2 and [H], the O2 eq shifts right which facilities O2 unlading and CO2 loading