Eukaryotic cells can look very different from each other, depending on what their function is. Cells will become specialised, have a wide range of different jobs, and behave in many ways. Many cells are designed for just the one job. However, there are some cells, like microglia in the brain, which can multi-task!
Microglia are the primary immune cells in the central nervous system (the brain and spinal cord). You will be familiar with neurons from your science lesson – and probably think that the brain is solely made of neurons. But in fact, about half of the mass of our brain is composed of glia cells which support the neurons. The smallest of these glial cells is the microglia. They actually only take up about 10% of our brain – but are really important in keeping it clean and healthy.
They are constantly on high alert, their branches reaching out to all the cells around them, all the time. If they do not detect danger they will remain in a “resting state”. But, the second they spot anything wrong, for example a pathogen or too much protein, they transform. They become blob like, flattening, and their branches shortening. After this they move to whatever the problem is and engulf it.
Unfortunately, like most things, these cells can lose control and actually cause disease. As well as engulfing what is not wanted in the brain, they also cause inflammation in a particular area, in order to kill whatever is there. If there is too much inflammation and it lasts too long however, it can destroy healthy cells.
Not only are they involved in preventing disease, but also in brain development. They will engulf synapses (connections between neurons) which are unused – helping learning processes. Scientists also believe they could be responsible for memory loss in old age. As they get older, they get larger, losing some of their branches. Naturally, this makes them less able to get rid of unwanted synapses needed to learn and remember things!
To help you understand, check out Part 2 of our “How to work with Cell Biology” guide. This describes the structure of different cells, and how they are adapted. It also includes some GCSE questions for you to practice, and answers to check your understanding.
Click on the picture below to see the guide.
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