Why does increased CO2 reduce affinity of haemoglobin for O2
Key Terms
Why does increased CO2 reduce affinity of haemoglobin for O2
Bohr effect
Increases CO2 conc. reduces haemoglobin affinity for O2 Actively repairing tissues produce more CO2 so more O2 is needed More carbonic acid, more H...
Bohr shift
Refers to the fact that O2 dissociation curve shifts down and to the right as CO2 conc increases
Lymph
Excess tissue fluid that is not returned to the blood vessel Contains less oxygen and more fatty acids
What causes the ‘lub dub’ sound
Closing of the AV valves
How do blood vessels maintain pressure
Narrow folded lumen in artery Elastic fibres recoil Smooth muscle contracts to constrict vessels
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| Term | Definition |
|---|---|
Why does increased CO2 reduce affinity of haemoglobin for O2 | CO2 converts to HCO3- Releases H+, lowers pH of cytoplasm Alters tertiary structure of haemoglobin and reduces affinity |
Bohr effect | Increases CO2 conc. reduces haemoglobin affinity for O2 Actively repairing tissues produce more CO2 so more O2 is needed More carbonic acid, more H+ in cytoplasm |
Bohr shift | Refers to the fact that O2 dissociation curve shifts down and to the right as CO2 conc increases |
Lymph | Excess tissue fluid that is not returned to the blood vessel Contains less oxygen and more fatty acids |
What causes the ‘lub dub’ sound | Closing of the AV valves |
How do blood vessels maintain pressure | Narrow folded lumen in artery Elastic fibres recoil Smooth muscle contracts to constrict vessels |
How do blood vessels withstand pressure | Collagen provides structural support | Elastic fibres stretch |
Why do we form adult haemoglobin | So the conc. gradient is maintained if the baby has a child | Fetal haemoglobin will not readily dissociate to release O2 for actively respiring tissues |
What happens to H+ ions after H2CO3 dissociates | H+ ions build up in RBC, pH decreases Affects 3’ structure Affinity for O2 decreased Oxyhaemoglobin dissociates into Hb and O2 |
Haemoglobinic acid | Unsaturated Hb binds with H+ | Restores pH |
HbO8 | Saturated haemoglobin 4 haem groups -> each bind to an O2 molecule Releases 4 O2 —> taken to plasma then respiring tissues |
Disadvantage of haemoglobin not having membrane bound organelles | Limited life span (cannot undergo mitosis) Limited respiration No protein synthesis |
Why don’t erythrocytes use any of the oxygen it is transporting | Erythrocytes lack mitochondria so do not respire aerobically Moved by mass flow so needs less ATP for metabolic processes |
Why does blood off load more oxygen to actively respiring tissues than to resting tissues | More CO2 Lowered affinity of Hb for O2 Dissociation of carbonic acid More oxygen released at same pO2 |
Calculating cardiac output | Heart rate * stroke volume |
How do vessels and arteries carry fluids | Mass flow |
Why do animals need specialised transport systems | Metabolic demands SA:V Hormones/ enzymes made in one place and required in another Waste products of metabolism need to be removed and transported to excretory systems Food digested needs to be transported to each cell for respiration |
Functions of the blood | Transport of: Oxygen to and CO2 from respiring cells Digested food from the small intestine Nitrogenous waste products from the cells to the excretory system Chemical messenger (hormones) Platelets to damaged areas Cells and antibodies in immune response Maintenance of steady body temp Acts as a buffer |