Mass transport in animals Flashcards
What is haemoglobin and its structure?
Protein with a quaternary structure (EA)
A quaternary structure is when it consists of more than 1 polypeptide chain. Haemoglobin contain a haem group where oxygen binds. Each haem group has an iron ion (Fe2+) that gives haemoglobin its red colour.
Where does oxygen bind onto in haemoglobin?
Onto the haem group.
What does affinity of haemoglobin for oxygen mean?
The ability of haemoglobin to attract or bind oxygen
What does saturation of haemoglobin with oxygen mean?
When haemoglobin is holding the maximum amount of oxygen it can
What does loading / association of haemoglobin mean?
The binding of oxygen to haemoglobin
What does unloading/ disassociation of haemoglobin mean?
When oxygen unbinds from haemoglobin.
What does the oxyhaemoglobin disassociation graph show?
It shows that at a high partial pressure of oxygen, haemoglobin will be almost completely saturated with oxygen. This means that oxygen is loaded in regions with a high partial pressure of oxygen e.g. lungs (alveoli). At lower partial pressures of oxygen, haemoglobin isn’t as saturated and therefore has a low affinity and will not attract oxygen efficiently. This means that oxygen is unloaded in regions with a low partial pressure of oxygen e.g. respiring tissues.
Why is it an advantage if oxygen is unloaded into regions with a low partial pressure of oxygen?
The haemoglobin is unloading the oxygen at sites where it is needed such as respiring tissues.
What is partial pressure?
The measure of the concentration of a particular gas in a mixture of gases or liquids.
What is cooperative binding?
When each molecule of oxygen binds, it changes the shape of the haemoglobin in a way that makes it easier for further oxygen molecules to bind.
Why is the oxyhaemoglobin disassociation graph an s-shape.
Because the increasing partial pressure of oxygen is not linear to the saturation of haemoglobin. This is because as the saturation of haemoglobin increases, it makes it harder for the final oxygen molecules to bind because there is already enough.
What is the Bohr effect?
When carbon dioxide is released by respiring cells, the affinity of haemeoglobin for oxygen decreases. Carbon dioxide creates slightly acidic conditions which change the shape of the haemoglobin protein, thus making it easier for the oxygen to be released. This shifts the curve to the right.
Describe the muscle the heart is made up of.
Cardiac muscle
- Thick muscular layer
- It is myogenic which means it can contract and relax without nervous or hormonal stimulation
- It never fatigues, as long as it has a supply of oxygen
Describe the coronary arteries.
- Blood vessels that surround the heart and supply the cardiac muscle with oxygenated blood.
- They branch off from the aorta.
What happens in coronary arteries become blocked?
The cardiac muscle will not receive any oxygen therefore the cells will not be able to respire and die. This results in a myocardial infraction (heart attack)
What are features of the atria?
Thin muscular walls because they do not need to contract as hard since they are not pumping blood far.
Elastic walls to stretch when blood enters.
What are the features of the ventricles?
Thicker muscular walls which creates a high blood pressure that allows blood to flow longer distances to the lungs and entire body
Which ventricle out of the right and the left has thinner walls and why?
The right ventricle has thinner walls compared to the left ventricle because it pumps blood to the lungs which has to be at a low pressure to prevent damage to the capillaries in the lungs and so blood flows slowly to allow gas exchange to occur.
What are the 4 major blood vessels in the heart?
- Right and left pulmonary artery
- Right and left pulmonary vein
- Aorta
- Vena cava
Where do the 2 veins carry blood from and to?
Vena cava:
- Carries deoxygenated blood from the body into the right atrium
Pulmonary vein:
- Carries oxygenated blood from the lungs to the left atrium
Where do the 2 arteries carry blood from and to?
Pulmonary artery:
- Carries deoxygenated blood from the right ventricle to the lungs to become oxygenated.
Aorta:
- Carries oxygenated blood from the left ventricle to the rest of the body.
Name the valves in the heart and where they are found.
Semi-lunar valves:
- Between the ventricles and the arteries, found in the aorta and pulmonary vein.
Atrioventricular valves:
- Found between atria and ventricles.
- Bicuspid is left side, tricupsid is right
What do valves do?
The open when the pressure is higher behind the valves and close when the pressure is lower in front of the valves to prevent the backflow of blood
What are the 3 stages the cardiac cycle is split into?
Diastole
Atrial systole
Ventricular systole
