Mass Transport in animals and circulatory system Flashcards
describe the structure of haemoglobin.
a quaternary structure protein as it consists of four polypeptide chains
each polypeptide carries a haem group which carry an iron ion can that can carry one oxygen molecule
what is partial pressure?
the concentration of gas in the cells
how does a dissociation curve work?
-the further left the curve is the greater the affinity for oxygen, so oxygen loads more readily and unloads less easily
-the further right the curve is the lower the affinity for oxygen, so oxygen loads less readily and unloads more easily
how does partial pressure of oxygen ensure that oxygen is transported from the lungs to the respiring tissues?
-the partial pressure influences the affinity of haemoglobin for oxygen
-at a high partial pressure (in the lungs) the haemoglobin has a high affinity for oxygen so oxygen readily associates to the haemoglobin to form oxyhaemoglobin meaning the percentage saturation is high
-at a low partial pressure (in the respiring tissues) the haemoglobin has a low affinity for oxygen so oxygen readily dissociates meaning the percentage saturation is low
describe the role of haemoglobin
component of red blood cells.
the oxygen molecules bind to the haem groups and are transported around the body to respiring tissues
how does the partial pressure of carbon dioxide affect oxygen and haemoglobin binding?
-the bohr effect states that as partial pressures of carbon dioxide increase the conditions become acidic causing the haemoglobin to alter in shape
-this means the affinity for oxygen therefore decreases so oxygen readily dissociates in given partial pressure
-this is known as the Bohr effect
how does the saturation of haemoglobin affect oxygen and haemoglobin binding?
-the binding of oxygen has a cooperative nature
-it is difficult for the first oxygen to bind
-once the first oxygen binds it changes the haemoglobins shape which uncovers haem group binding sites and makes it easier for the second and third molecules to bind which is known as positive cooperativity
-it is then slightly harder for the fourth oxygen to bind as there is a low chance of finding a binding site
how does the haemoglobin of an organism adapt to its environment
-organisms in environments with low oxygen concentrations will have haemoglobin which has a higher affinity to oxygen
-organisms that are active and have a ow demand for oxygen will have haemoglobin with a lower affinity to oxygen
how is foetal haemoglobin different to adult haemoglobin
-foetal haemoglobin has a higher affinity for oxygen
-this means maternal haemoglobin will dissociated itself in the placenta so the foetal haemoglobin can load with oxygen
-this ensures the foetus receives a sufficient supply of oxygen
what are three common features of a mammalian circulatory system.
-suitable medium for transport, in mammals this is the blood which is water based so to allow many substances to dissolve in it
-means of moving the medium and maintaining pressure, in mammals the heart pumps the blood
-means of controlling the flow, in mammals they use valves
how are atria adapted to their function?
thin-walled and elastic which allows them to stretch when they are filled with blood
how are ventricles adapted to their function
they have thick muscular walls that contract to pump the blood at a high pressure, the left ventricle has a thicker muscle as it pumps blood to the whole body
how are arteries adapted to their function
-arteries carry blood away from the heart to the rest of the body under high pressure
-have a thick cell wall to handle high pressure without tearing
-contain elastic tissue layer which enables them to stretch when under high pressure and recoil as ventricle relaxes
-contain smooth muscle which enables them to control blood flow by contracting to move blood along
-they have a narrow lumen to increase and maintain high blood pressure
how are veins adapted to their function
-transport blood back to the heart under low pressure
-wide lumen to maximise blood flow to the heart
-thin walls as the blood transported under low pressure
-valves prevent the back flow of blood
what is the role of tendons in the heart?
prevent inversion of valves due to high pressure