The heart Flashcards
What are the 4 components of blood?
- Red blood cells
- Platelets
- Plasma
- White blood cells
What are the 2 adaptations of red blood cells?
- Large SA for faster diffusion
- No nucleus so more space for haemoglobin
What is haemoglobin?
A quaternary protein with a haem group at the centre of each polypeptide chain containing Fe2+
What do haem groups contain?
One Fe2+ which one oxygen molecule binds to
What is the term used to describe the attraction between haemoglobin and oxygen?
Affinity
Where does haemoglobin load/associate with oxygen?
Lungs
Where does haemoglobin unload/dissociate with oxygen?
Respiring tissues
What is % saturation of haemoglobin?
A measure of how oxygenated blood is
What is partial pressure of oxygen?
A measure of concentration of oxygen not attached to the haemoglobin molecule
Why does the second oxygen molecule attach easier?
Each time a molecule of oxygen attaches the whole haemoglobin changes shape which exposes more of the next O2 binding site and makes it easier for the next O2 molecule to attach
What is the advantage of the sigmoid shape of an oxygen dissociation curve?
Shows that O2 isn’t unloaded until it reaches the respiring tissues
What does the Bohr effect curve shifting right mean?
More respiration so higher partial pressure of O2 and Hb has lower affinity for O2 so more O2 unloaded at respiring tissues
What does the Bohr effect curve shifting left mean?
Lower partial pressure of O2 and Hb has higher affinity for O2 so more O2 loaded at the lungs
What is systole?
Contraction (occurs separately in atria and ventricles)
What is diastole?
Relaxing