2. Cardio- Transportation Of Oxygen

Question 1

Transportation of oxygen

Answer 1

• most of our transported oxygen brackets 97% combines with haemoglobin (an iron containing pigment found in red blood cells) to form oxyhaemoglobin. The 3% dissolves in the plasma. Training increases levels of haemoglobin
• myoglobin, also known as ‘muscle haemoglobin’ acts as a store of oxygen in the muscle fibres, which can be used quickly during exercise. Training also increases levels of myoglobin

Question 2

Oyhaemoglobin dissociation curve (exercise, partial pressure, Bohr shift)

Answer 2

The Oxy haemoglobin dissociation curve represents the relationship between oxygen and haemoglobin. From this curve you can see that in the lungs there is almost full saturation (concentration) of haemoglobin, but the tissues (muscles) The partial pressure of oxygen is lower because haemoglobin gives up some of its oxygen to the muscles and is therefore no longer fully saturated

when looking at the graph
> at rest the high partial pressure of oxygen in the lungs means haemoglobin is almost completely saturated with oxygen
> in the tissues the partial pressure of oxygen is lower therefore the haemoglobin gives up some of its oxygen to the tissues

-during exercise this S shaped curve shifts to the right because, when muscles require more oxygen, the dissociation of oxygen from haemoglobin in the blood capillaries to the muscle tissue occurs more readily. This shift to the right is known as the Bohr shift.

-The Bohr affect refers to the shift in the oxygen dissociation curve caused by changes in the concentration of carbon dioxide or the pH of the environment. It is caused by 3 factors:
•a decrease in the blood pH
•an increase in blood temperature
•an increase in blood CO2

Question 3

Redistribution of blood- vascular shunt (vasoconstriction/vasodilation)

Answer 3

both blood pressure and bloodflow are controlled by the vasomotor centre, located in the medulla oblongata of the brain. During exercise chemical changes, such as increases in carbon dioxide and lactic acid are detected by chemoreceptors. These receptors send impulses to the vasomotor centre, which redistributes blood flow through sympathetic stimulation. An increase in sympathetic stimulation causes vasoconstriction and a decrease in stimulation by the sympathetic nerves causes vasodilation

• vasoconstriction is the narrowing of the blood vessels to reduce blood flow
• vasodilation is the widening of the blood vessels to increase blood flow

During EXERCISE more oxygen is needed at the working muscles, so vasodilation will occur in the arterioles supplying these muscles to increase blood flow. Vasoconstriction Will occur in the arterioles supplying non-essential organs such as the intestines and liver

Question 4

Redistribution of blood is important to:

Answer 4

• increase the supply of oxygen to the working muscles
• remove waste products from the muscles such as carbon dioxide and lactic acid
• ensure that more blood goes to the skin during exercise to regulate body temperature and get rid of heat through radiation, evaporation and sweating
• Direct more blood to the heart, because it is a muscle and requires extra oxygen during exercise

Question 5

What is the difference between haemoglobin and myoglobin?

Answer 5

Haemoglobin transports oxygen in the blood. Myoglobin stores oxygen in the muscles