Oxygen In The Blood Flashcards
What are some of the issues involved in transporting oxygen dissolved?
Oxygen is not very soluable in water p, is far less soluable than CO2, only small amounts dissovled and therefore would need a huge cardiac output to get the oxygen around the body
What are the two main oxygen binding pigaments?
Haemooglobin and myoglobin
What are some of the key structural features of myoglobin?
Contains haem, is a monomer and found in the muscle cells, has a single sturcture to heamoglobin but has a single subunit
Describe some fo the features of the myoglbin saturation curve?
Oxygen saturation compared to the partial pressure, is a hyperbolic curve, saturation occurs when all the pigemnt available is bound to oxygen and can be used to see how much O2 will be given up at a given partial pressure
What are some pf the structural features of heamoglobin?
Is a teramer, binds four oxygen molecules, there are two alpha and two beta subunits.
What are the two different states of the heamoglobin moelcule?
There is a t state, which is tense and has a low affintiy for oxygen, and there is a hihg affinity r relaxed state
What are some of the features of the haemoglobin dissociation curve?
Is a sigmodial curve, indicating the stage where the hameoglobin is found within the t state and therefore has a lower affinity for oxygen, and has a starutation at about 9-10kpa
What are some of the features of oxygen biniding in the aterial blood in the lungs?
Alevolar pO2 is 13.3 kPa and therefore the hameoglobin is well saturated if a patient has a funcitonal condition such as anemia the oxygen content will be normal however the oxygen saturation in the blood will be lower
What are some of the features of the heamoglobin in the tissues?
Tissue PO2 depends on how metabollically active the tissues are, Hb saturation drops to about 65%
What are some fo the features of the heamoglobin in the venous blood?
Only about 27% of th oxygen has been realeased, at a low tissue pO2 more oxygen will be realeased
How low can the tissue pO2 get?
Tissue pO2 must be low enough to drive the diffsuion of the heamoeglobin to the cels, however the higer the capilalry density the lower the pO2 can fall, but it cannot fall below 3kPa wihtin most tissues, very metabolically active tissues will have a lower capillary density
What are some of the factors that lead to the maximum unloading of oxygen?
Maximum unloading occurs in tissues where the pO2 has fallen ti tisseu p, and also in the tissue that there is a lower metabolic activity
What are some fo teh features of the bohr shift?
As the PH falls it lowers the oxygen affinity of hameoglobin, and these acid conditions shift the curve to the right in what is known as the bohr shift, as a decreasing pH promotes the T state of hameoglobin whereas the increasing pH promotes the r state of hamoeglobin
What are the effects of 2,3 diphosphoglycerate
Increases at high altidues or in anaemia, and helps to shift the curve to the right, and therefore promotes the realease of oxygen in the tissues,
What are some of the features of carbon monoxide poisioning?
Reacts with Hb to form CoHb, increases the affinty in the affecting cells for O2 and therefore they do not realease O2 at the tissues, and fata if CoHb is above 50%
