Week 10 - Blood, Lymph, and Oedema Flashcards
1
Q
Why is plasma not used for oxygen transport?
A
- not soluble
- equilibrium reached quickly
- no more oxygen can dissolve in
2
Q
What is the Bohr shift?
A
- right shift
- reduced affinity
- in tissues
- low oxygen partila pressure
- Hb is unloaded
- 75% saturated
- increased H+ concentration from CO2
- H+ binds to Hb
- changes protein conformation
3
Q
What is the Haldane shift?
A
- left shift
- increased affinity
- in lungs
- high oxygen partial pressure
- Hb is loaded
- increased pH
- reduced affinity for CO2 (right shift for CO2 graph)
4
Q
What is the chemical equation for carbon dioxide?
A
- CO2 + H2O
- catalysed by carbonic anhydrase
- makes H2CO3
- quickly dissociates to HCO3- + H+
5
Q
How does temperature affect oxygen affinity?
A
- decreased temperatures increase affinity
- Haldane shift
- lungs inhale cold air
- increased temperatures decrease affinity
- Bohr shift
- respiring muscles release (heat) energy
6
Q
How is CO2 transported?
A
- diffuses into plasma
- some dissolved
- more bound to Hb
- most as bicarbonate
- conversions happen inside erythrocytes to keep equilibrium tipped and more CO2 to diffuse
- conversion to bicarbonate also keeps equilibrium tipped so more CO2 goes into erythrocytes
7
Q
What is albumin?
A
- large protein in blood plasma
- transfers hormones and fatty acids
- buffers pH
- keeps it strictly at 7
- creates (constant) osmotic gradient from interstitial fluid
- arterial end of capillary has high blood pressure
- net pressure out
- venous end has lower blood pressure
- net pressure in
- to maintain equilibrium
- and prevent oedema
- lack of albumin prevents net pressure in
