When students are asked to compare and contrast two types of cell death: necrosis and apoptosis, the same answers come back:
Apoptosis is programmed cell death.
Necrosis is premature cell death.
All the right things are said but when we then look at a biopsy, they are unsure if necrotic areas are showing necrosis or apoptosis. They don’t seem to be getting the underlying concepts.
So, what do you think of the following ‘car death’ analogy?
Scenario 1: Apoptosis
You are driving along the highway and notice a warning light and there is a strange noise in the car. You pull over and a tow truck takes away the car. The car is finished but there was minimal or no damage to the surrounding cars and road. The car had just come to the natural end of its life. The car can go to the scrap yard, recycling useable pieces.
Scenario 2: Necrosis
You are driving along a busy highway and something external hits the car – bullet or lightning – and the car explodes. Not only has the car had a ‘premature death’ but it may have damaged the cars around it and/or the road. This can disrupt traffic as well as leave a permanent mark. The crew that comes in to clean up the bits is analogous to the immune system (this last sentence going too far?).
What do you think? Does the analogy work? Do you think it helps people see the underlying differences between the two processes?
This was a quick out-of-thin-air analogy so I accept that it might not work and I welcome all suggestions!