3.3.4 Mass transport

Question 1

What is the pathway of blood around the right side of the heart?

Answer 1

• Deoxygenated blood arrives at the right atrium from the vena cava filling the atrium and increasing the pressure.

• The atrial muscle contracts reducing the volume and increasing the pressure in the atrium until it is greater than the ventricle - this forces the blood through the atroventricular valve into the right ventricle.

• The increase in pressure of the ventricle closes the atrioventricular valve, preventing back flow of blood.

• Then the right ventricle muscle contracts reducing the volume and increasing the pressure until it is greater than in the pulmonary artery, this forces the blood through the semilunar valve.

• The pressure in the right pulmonary artery increases causing the semilunar valve to close prevening back flow.

Question 2

Describe the cardiac cycle through the left side of the heart.

Answer 2

• Oxygenated arrives at the left atrium from the pulmonary vein filling the atrium increasing the pressure.

• The atrial muscle contracts reducing the volume and increasing the pressure in the atrium until it is greater than the ventricle - this forces the blood through the atrioventricular valve into the left ventricle.

• The increase in pressure of the ventricle closes the atrioventricular valve, preventing back flow of blood.

• Then the left ventricle muscle contracts reducing the volume and increasing the pressure until it is greater than in the aorta. This forces the blood through the semilunar valve.

• The pressure in the aorta increases causing the semilunar valve to close to prevent back flow.

Question 3

What is cooperative binding between oxygen and haemoglobin?

Answer 3

• As 02 loads to haemoglobin, its binding cause the haemoglobin to change shape.

• This change of shape makes it easier for more oxygen to load.

• Until all the haem groups are occupied and the haemoglobin is saturated (full).

• This is called co-operative binding.

Question 4

How is tissue fluid formed? half complete

Answer 4

• A higher hydrostatic pressure of bloody at the arterial end of capillary

• water and soluble molecules pass out, whilst proteins remain

Question 5

Explain the Bohr shift and the role of CO2 in terms that of oxygen disassociation?

Answer 5

• In exercising or organisms with high metabolism

• CO, in tissues reduces the affinity of oxygen to haemoglobin (it’s acidic/changes Hb shape)

• In tissues where there is lots of respiration the oxygen is **more easily unloaded **- this makes the curve shift to the right.

• This can replace used 02 easier

• The impact of CO2 is called the Bohr Shift

Question 6

Left Bohr shift. Click for more. 😉

Answer 6

Usually in low oxygen environments e.g, womb, high altitude, under water.

1. Higher affinity for oxygen at lower
   ppO2
2. Oxygen associates/loads more readily.
3. More oxygen can bind where little oxygen is available e.g foetus.

Question 7

Right Bohr shift. Click for more. 😉

Answer 7

Usually in metabolically active organisms e.g. mice or runners Bohr shift

1. Lower affinity of oxygen at higher ppO2
2. Oxygen disassociates/unloads more readily.
3. More oxygen available in tissues for More aerobic respiration.