Explain how during a game of a rugby, an increase in blood Co2 will cause heart rate to rise (4 marks)
As the muscles in the body respire and use up the oxygen, Co2 is produced and thus blood acidity in the bloodstream rises 2) This change is detected by the chemoreceptors 3) These impulses are then sent to the Medulla Oblongata in the Cardiac control centre 4) nerve impulses are then sent to the SAN which causes increases sympathetic nervous impulses and thus heart rate rises