Mass transport in animals Flashcards
What is the Bohr effect?
The effects of carbon dioxide concentration on the dissociation of oxyhaemoglobin. Haemoglobin will have a reduced affinity for oxygen in the presence of carbon dioxide.
Why is haemoglobin’s reduced affinity for oxygen in the presence of carbon dioxide helpful?
Carbon dioxide concentration is higher at respiring cells therefore more oxygen will disassociate from haemoglobin at these respiring cells so more oxygen for aerobic respiration. Therefore more ATP is produced.
Why is the binding of the second and third oxygen to haemoglobin easier than the first?
The cooperative nature of oxygen binding causes a conformational change in the shape of haemoglobin caused by the binding of the first oxygen which makes the binding of further oxygen easier by uncovering a new binding site.
Does a mouse’s haemoglobin have a higher or lower affinity for oxygen than a humans?
A lower affinity because the mouse has a higher metabolism so oxygen has to be more readily available for aerobic respiration.
What type of circulatory system do mammals have?
A closed, double circulatory system.
What can the blockage of the coronary arteries lead to?
A myocardial infarction (heart attack).
Name the two different groups of valves in a human heart:
Atrioventricular and semi-lunar valves.
What is the equation for cardiac output?
CO = stroke volume × heart rate
Why are artery walls thicker than a vein?
Blood moves through a much higher pressure in an artery therefore thicker walls are needed to prevent bursting.
Name the three stages of the cardiac cycle:
Diastole, atrial systole, ventricular systole.
What is tissue fluid?
Fluid containing water, glucose, oxygen, amino acids, and ions that bathe the tissues.
How is tissue fluid formed?
Capillaries have small gaps in their walls (fenestrations) so that liquid and small molecules can be forced out. This is due to the high hydrostatic pressure as blood enters the arterial end of the capillary. This is known as ultrafiltration.
How is the tissue fluid reabsorbed?
Some are reabsorbed through osmosis at the venule end of the capillary because there is lower hydrostatic pressure and large proteins remain dissolved in the capillary.
The rest will be absorbed into the lymphatic system.
Why do arteries have a thick elastic layer?
To help maintain blood pressure. The walls can stretch and recoil in response to the heartbeat.
