Respiratory [Gas Transport]

Question 1

Two methods for carrying O2 in blood

Answer 1

Binding with Hb

Dissolving in plasma

Question 2

Hb contains a ______ and 4 _____ groups. Each group binds with an O2 using a ____ in a _____ fashion. The equation is ______.

Answer 2

Polypeptide chain (globin)
Ferrous iron groups (haem)
Salt bridge
Cooperative

Hb + O2 = HbO2

Question 3

The oxygen dissociation curve is the _____ vs ______.

Answer 3

% saturation of O2

Partial pressure of O2

Question 4

The oxygen dissociation curve shows that the PO2 in tissues is about ____ and ____ in lungs. O2 is unloaded in veins/arteries and loaded in veins/arteries. O2 loses its ____ at tissues because of the high/low pH

Answer 4

40
100
Veins
Arteries 
Affinity
Low

Question 5

I = partial pressure of O2 when ____ is ____. The _____ of O2 is independent/dependent on amount of Hb present.

Answer 5

Blood is 50% saturated
% saturation
Independent

Question 6

The curve for blood O2 content is ____ vs ____.

Answer 6

O2 content mL/L

PO2

Question 7

Anaemia has reduced _____ by ____%. The ____ is 100% but the ____ is loser.

Answer 7

Hb
50%
Saturation
Content

Question 8

What is a physiological advantage of the O2 dissociation curve? Think of the steep part at the start.

Answer 8

Tissue where PaO2 is low, Hb releases heaps of O2 for only a small drop in capillary PO2.

Question 9

4 Factors affecting O2 dissociation curve that cause a Bohr shift

Answer 9

pH decrease. More O2 released: HbO2 + H+ = HHb + O2.

Co2 high, increase H+ and binds w Hb to displace O2

Temperature

DPG high

Question 10

CO2 is transported in 3 ways. Give the ways without the eqns.
The first 2 occur in ___ and the last in ___.

Answer 10

1. Dissolved in solution
2. Combines with Nh2 proteins to form carbamino
3. Carried in HcO3 form

Plasma
RBC

Question 11

Co2 is transported in 3 ways. Give the equations for:

1. Dissolved in solution
2. Combines with Nh2 proteins to form carbamino
3. Carried in HcO3 form

Answer 11

1. CO2 + H2O = H2CO3 = H+ + HCO3-
2. R-NH2 + CO2 = R-NHCOO + H+
   H+ are buffered by proteins
3. CO2 + H2O = H2CO3 = H+ + HCO3

Question 12

Name the enzyme that speeds up this reaction and where it occurs

CO2 + H2O = HCO3 = H+ + HCo3

Answer 12

Carbonic anhydrase

In RBC

Question 13

H+ are buffered by ___ to form ___

Answer 13

Hb

HHb

Question 14

The Co2 dissociation curve is ___ vs ____. And shows 1/2/3 curves increasing exponentially. The top one is arterial/venous because more CO2 is taken bc ____. The shift to the right is called the ____.

Answer 14

CO2 mL/L
PCO2
2
Venous
HB has more affinity for CO2 than HbO2 in arterial.
Haldane effect

Question 15

The ____ curve can’t be saturated reflecting its dependence on ____ ____ and ___.

Answer 15

CO2 dissociation curve
PCO2
High CO2 solubility
Methods of transport

Question 16

Peripheral chemoreceptors location (___ and ____. Connected to brain stem via ____

Answer 16

Aortic arch (aortic bodies) and carotid artery bifurcation (carotid bodies). Connected to brain stem via vagal and glossapharyngeal nerves.

Question 17

Peripheral chemoreceptors stimulants

Answer 17

Hypoxia
Protons
Carbon dioxide

Question 18

Reflex response of periphery chemoreceptors. Fast/slow

Answer 18

Increase rate and depth of breathing by acting on brain stem respiratory network.
Fast.

Question 19

Location of central chemoreceptors

Answer 19

Neurons and/or astrocytes beneath surface of ventral medulla.

Question 20

Stimulants of central chemoreceptors. Fast/slow

Answer 20

H+ from when CO2 diffuses across BBB and dissolved in CSF.

Slow

Question 21

Why is central chemoreceptors slow?

Answer 21

Wait for CO2 to dissolve and low levels of enzyme carbonic anhydrase in CSF

Question 22

Reflex response of central chemoreceptors

Answer 22

Increase minute volume by acting on brain stem respiratory network. Increase in PCO2 (hypercanja) increases this in a dog-leg effect.

Question 23

___% of the dog leg effect is from chemoreceptors.

Chemoreceptors are essential because if they fail you get a disease called ____ which can kill you in your ___.

Answer 23

80.
Ondine’s curse (congenital hypoventilatory syndrome).
Sleep

Question 24

What is the order from highest to lowest of the 4 ways CO2 can be transported in blood?

Answer 24

1. As HCO3- ions
2. Combined to NH2 groups of plasma proteins such as Hb
3. Dissolved in solution
4. As H2CO3 and CO3- ions (minor)

Question 25

CO2 binds to ____ on Hb

Answer 25

Globin groups

Question 26

PO2 ____ must be higher than pO2 ____ for oxygen to diffuse into blood. P increases for exercise.

Answer 26

Alveolar

Blood

Question 27

Dog leg graph

Answer 27

Ventilation y

PCO2 x axis