Circulatory System Flashcards
What is haemoglobin?
Protein with a quaternary structure
More than one polypeptide chain and a prosthetic group
Why do red blood cells have a biconcave shape?
Maximizes surface area so maximum hemoglobin can be loaded
Explain the shape of the oxygen dissociation curve
The gradient of the curve is shallow at first because the first oxygen molecule finds it difficult to bind to the hemoglobin.
When the first oxygen molecule binds the shape of the protein changes which makes it easier for other oxygen molecules to bind
POSITIVE CO OPERATIVITY
The gradient then flattens off because it is harder for the last oxygen molecule to find the last empty binding site
Explain the effect of heat on hemoglobin affinity
When tissues respire they produce heat, and the partial pressure of O2 goes down, when hemoglobin reaches the O2 gets unloaded b cause the heat causes the hemoglobin to change shape which lowers its affinity for oxygen.
What effect does CO2 have on hemoglobins oxygen affinity?
In respiring tissues CO2 is being produced so hemoglobins affinity for oxygen is reduced because CO2 causes the hemoglobin to change shape because it changes the pH.
What type of conditions require the oxygen dissociation curve to be shifted to the left?
When oxygen levels are low and animals need to be able to have a higher affinity for oxygen at lower partial pressures
What type of conditions require the oxygen dissociation curve to be shifted to the right?
When animals have a large surface area to volume ratio and lose heat rapidly.
Plenty of oxygen is unloaded to tissues at all times
Label the heart
See book lol
Describe diastole
Ventricles and atria both relax
Blood returning to the heart fills the atria
Pressure in atria > pressure in ventricles
AV valves open
Blood flows from atria to ventricles
Describe Atrial Systole
Atria both contract
Pressure in atria +
More blood goes to ventricles
AV valves open
Describe ventricular systole
Ventricles contract
Pressure in ventricles > pressure in atria
AV valves close
Pressure of ventricles > arteries
pulmonary and aortic valves are forced open
blood is pushed out of ventricles
SL valves close
Why do mammals have a double circulatory system?
So the pressure can be changed
