Respiratory [Gas Transport] Flashcards
Two methods for carrying O2 in blood
Binding with Hb
Dissolving in plasma
Hb contains a ______ and 4 _____ groups. Each group binds with an O2 using a ____ in a _____ fashion. The equation is ______.
Polypeptide chain (globin)
Ferrous iron groups (haem)
Salt bridge
Cooperative
Hb + O2 = HbO2
The oxygen dissociation curve is the _____ vs ______.
% saturation of O2
Partial pressure of O2
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
40 100 Veins Arteries Affinity Low
I = partial pressure of O2 when ____ is ____. The _____ of O2 is independent/dependent on amount of Hb present.
Blood is 50% saturated
% saturation
Independent
The curve for blood O2 content is ____ vs ____.
O2 content mL/L
PO2
Anaemia has reduced _____ by ____%. The ____ is 100% but the ____ is loser.
Hb
50%
Saturation
Content
What is a physiological advantage of the O2 dissociation curve? Think of the steep part at the start.
Tissue where PaO2 is low, Hb releases heaps of O2 for only a small drop in capillary PO2.
4 Factors affecting O2 dissociation curve that cause a Bohr shift
pH decrease. More O2 released: HbO2 + H+ = HHb + O2.
Co2 high, increase H+ and binds w Hb to displace O2
Temperature
DPG high
CO2 is transported in 3 ways. Give the ways without the eqns.
The first 2 occur in ___ and the last in ___.
- Dissolved in solution
- Combines with Nh2 proteins to form carbamino
- Carried in HcO3 form
Plasma
RBC
Co2 is transported in 3 ways. Give the equations for:
- Dissolved in solution
- Combines with Nh2 proteins to form carbamino
- Carried in HcO3 form
- CO2 + H2O = H2CO3 = H+ + HCO3-
- R-NH2 + CO2 = R-NHCOO + H+
H+ are buffered by proteins - CO2 + H2O = H2CO3 = H+ + HCO3
Name the enzyme that speeds up this reaction and where it occurs
CO2 + H2O = HCO3 = H+ + HCo3
Carbonic anhydrase
In RBC
H+ are buffered by ___ to form ___
Hb
HHb
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 ____.
CO2 mL/L PCO2 2 Venous HB has more affinity for CO2 than HbO2 in arterial. Haldane effect
The ____ curve can’t be saturated reflecting its dependence on ____ ____ and ___.
CO2 dissociation curve
PCO2
High CO2 solubility
Methods of transport
Peripheral chemoreceptors location (___ and ____. Connected to brain stem via ____
Aortic arch (aortic bodies) and carotid artery bifurcation (carotid bodies). Connected to brain stem via vagal and glossapharyngeal nerves.
Peripheral chemoreceptors stimulants
Hypoxia
Protons
Carbon dioxide
Reflex response of periphery chemoreceptors. Fast/slow
Increase rate and depth of breathing by acting on brain stem respiratory network.
Fast.
Location of central chemoreceptors
Neurons and/or astrocytes beneath surface of ventral medulla.
Stimulants of central chemoreceptors. Fast/slow
H+ from when CO2 diffuses across BBB and dissolved in CSF.
Slow
Why is central chemoreceptors slow?
Wait for CO2 to dissolve and low levels of enzyme carbonic anhydrase in CSF
Reflex response of central chemoreceptors
Increase minute volume by acting on brain stem respiratory network. Increase in PCO2 (hypercanja) increases this in a dog-leg effect.
___% 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 ___.
80.
Ondine’s curse (congenital hypoventilatory syndrome).
Sleep
What is the order from highest to lowest of the 4 ways CO2 can be transported in blood?
- As HCO3- ions
- Combined to NH2 groups of plasma proteins such as Hb
- Dissolved in solution
- As H2CO3 and CO3- ions (minor)
CO2 binds to ____ on Hb
Globin groups
PO2 ____ must be higher than pO2 ____ for oxygen to diffuse into blood. P increases for exercise.
Alveolar
Blood
Dog leg graph
Ventilation y
PCO2 x axis
