Lecture 19 Flashcards
What are the two forms of oxygen transport in the blood?
Dissolved and bound to haemoglobin
Why does oxygen dissolve poorly in blood?
Because of its warm temperature
How is oxygen carried in haemoglobin?
Bound to the iron
How many O2 molecules can haemoglobin carry?
Four as there are 4x haem structures with 1x iron on each
What is the binding curve relationship of O2 and haemoglobin?
Sigmoidal
Why is the binding curve relationship sigmoidal?
Because of the co-operative binding properties of haemoglobin
Describe the co-operative nature of haemoglobin
Binding affinity increases as more O2 binds, 1st is hardest to bind and 4th is easiest
What are the two jobs of haemoglobin?
To move oxygen from air in the alveolus to blood in the capillaries and to move oxygen from the blood in the capillaries to the surrounding tissues
How is haemoglobin able to preform both its jobs effectively?
Because of its co-operative nature
What are the two reasons for the relationship of the haem binding curve not being linear?
To allow the body to store O2 in reserve and adjust the distribution of O2 depending on the tissues metabolic needs
Is the haemoglobin binding curve static or dynamic?
Dynamic
What are the two ways the haemoglobin binding curve can be shifted?
Changing the pH and temperature of the blood
What has to happen to the pH and temp of blood to reduce O2 affinity?
Lowing pH and increasing temperature
What has to happen to the pH and temp of blood to increase O2 affinity?
Increase pH and decrease temperature
What does affinity mean?
How tightly the molecules are bound to each other. Lower O2 affinity for haemoglobin means it lets it go easier
What are the three forms of transportation for carbon dioxide in the blood?
Dissolved in plasma, bound to haemoglobin and converted into bicarbonate
How does bicarbonate form?
CO2 and H2O combine to form carbonic acid, which dissociates into bicarbonate and hydrogen ion, lowering the pH
Is O2 usage and CO2 production variable or static?
Variable
What are the four sensors that control breathing?
Chemoreceptors, baroreceptors, lung stretch receptors and protective reflexes
Is the information from sensors that control breathing afferent or efferent
Afferent
What area of the brain is the central controller of breathing?
Pons, medulla and some other parts
What are chemoreceptors?
Receptors that detect changes in O2 and CO2 levels in the blood
If O2 is up or CO2 is down what will the chemoreceptors do?
Send afferent input to the brain, resulting in increased breathing frequency and tidal volume
What are the primary chemoreceptors that control breathing?
CO2 receptors
What are the secondary chemoreceptors that control breathing?
O2 receptors
What are baroreceptors?
Blood pressure sensors
How does baroreception affect respiratory function?
If arterial BP decreases, less O2 is being delivered to tissues so the baroreceptors will send afferent signals to inform the brain and the brain will increase respiratory minute volume and the uptake of air
What is the function of the lung stretch receptors?
As the lungs inflate or deflate, afferent input is sent to the brain. Brain sends efferent output to prevent over stretch or deflation
What is the function of the protective reflexes?
To detect irritation and send efferent signals from brain to trigger coughing or sneezing
