Describe how a wave of excitation, which originates in the sinoatrial node (SAN) of the heart, eventually results in ventricular systole.
• SAN send a wave of depolarisation/excitation across the atria causing them to contract• wave cannot pass directly to the ventricle, due to the non-conductive tissue of AV-valves• wave reaches the AVN (in the septum)• passes down bundle of His• up the Purkinje fibres, causing ventricular systole
JG
Related Biology A Level answers
All answers ▸Emphysema is a disease of the lungs. Explain why people suffering from this condition may feel weak and short of breath.(6 marks)
When a nerve impulse arrives at a synapse, it causes the release of neurotransmitter from vesicles in the presynaptic knob. Describe how.
Explain how the physical properties of water enable organisms to survive over a range of temperatures.
Describe and explain the process of glycolysis