Mass transport (DWR) Flashcards
(30 cards)
What are the four main blood vessels involved in bringing blood to and from the heart?
Vena Cava, Pulmonary vein, Pulmonary artery, Aorta
What is the job of the vena cava?
Brings deoxygenated blood from the body to the right atrium.
What is the job of the pulmonary vein?
Bring oxygenated blood from the lungs to the left atrium
What is the job of the aorta?
Brings oxygenated blood from the left ventricle to the cells of the body
What is the job of the pulmonary artery?
Brings deoxygenated blood to the lungs from the right ventricle
What blood vessel supplies the heart with oxygen and why is it important?
Coronary artery. It is important as lack of blood flow to the heart can lead to myocardial infarction
Two types of chambers in the heart?
Atria and Ventricles, two on each side
Job of the atria
Upper chambers that collect blood coming in from the body or the lungs through veins. They have thinner walls than ventricles.
Job of the ventricles
Lower chambers that pump blood through arteries to the body or the lungs. They have thicker walls than arteries because they pump blood a longer distance.
Why does the left ventricle have a thicker wall than the right ?
The left ventricle has a thicker wall than the right as it has to pump blood a further distance around the whole body.
Job of the semilunar valves
Semilunar valves allow blood to be pumped forward into the arteries but prevent backflow of blood from the arteries into the ventricles.
How many oxygen molecules can each haemoglobin bind to?
4
Process by which haemoglobin binds with oxygen is called
Loading or Associating
Process by which haemoglobin releases oxygen is called
Unloading or Dissociating
High affinity haemoglobin
Associates easily but dissociates with difficulty
In what type of environment would high affinity haemoglobin be beneficial and why?
One with low partial pressure of Oxygen. Organisms can still achieve a good oxygen saturation in the blood at a low oxygen environment
Low affinity haemoglobin
Dissociates easily but associates with difficulty
In what type of organism would low affinity haemoglobin be beneficial and why?
Active ones as it promotes rapid release of oxygen to the constantly active and respiring tissues
Describe the shape of the oxygen dissociation curve
- The first oxygen molecule has difficulty binding to haemoglobin because the four polypeptide subunits are closely united, so the curve starts off shallow.
- The second oxygen molecule binds more readily, as the binding of the first molecule changes the shape of the molecule, making it easier for the second molecule to bind to another subunit. This is known as positive cooperativity.
- After the binding of the third molecule, probability of oxygen encountering an unoccupied subunit is reduced, so the gradient reduces and flattens off
A more leftward Oxygen dissociation curve indicates:
A higher affinity for oxygen
A more rightward Oxygen dissociation curve indicates:
A lower affinity for oxygen
Effect of Carbon dioxide concentration on haemoglobin affinity for oxygen
Haemoglobin has a reduced affinity for oxygen in the presence of carbon dioxide. This is because carbon dioxide is acidic in solution and the low pH disrupts the bonds in the protein and changes the shape, making it easier for oxygen to dissociate.
Why is the oxygen dissociation curve further to the left at the lungs?
At the gas exchange surface, the concentration of carbon dioxide is low as it has diffused across the surface and is excreted from the organism. This increases the affinity for oxygen, so a reduced carbon dioxide concentration shifts the curve to the left.
Why is the oxygen dissociation curve further to the right at respiring tissues?
At respiring tissues, the concentration of carbon dioxide is high as it is being released by the respiring tissues. This increases the pH and therefore decreases the haemoglobin affinity for oxygen, shifting the curve to the right.
