Transport

Question 1

The changes in blood pressure in the right atrium are the same as those in the left atrium. The changes in blood pressure in the right ventricle are different from those in the left ventricle. Explain why this is so.

Answer 1

• both atria pump blood the same distance to ventricles
• right ventricle pumps blood to lungs
• this is a short distance and a lower pressure
• there is less resistance in pulmonary circulation
• left ventricle pumps blood to the whole body
• more resistance in systemic circulation
• muscular walls the same thickness in atria
• right ventricle pumps with less force than the left

Question 2

Describe the effects of nicotine and carbon monoxide on the cardiovascular system

Answer 2

nicotine:

• increases heart rate
• increases blood pressure
• makes platelets ‘sticky’
• increases chance of blood clotting (promotes thrombosis)
• decreases flow of blood to extremities
• constriction of blood vessels

Carbon monoxide:

• combines with Hb to form carboxyhaemoglobin (higher affinity for haemoglobin than oxygen)
• reduces oxygen carrying capacity of haemoglobin
• promotes release of damaging free radicals
• causes platelets and neutrophils to stick together