Well that is a huge question that I don't expect you to answer here but check out this video where Steven Colbert challenges Steven Pinker to explain how the brain works in 5 words or less.
For this blog entry you might want to comment on a very key part of your brain that influences a great deal of your behavior: the amygdala.
Notice how it is directly connected to the hippocampus who's main function deals with memory. In addition researchers have mapped some of the connections the amygdala has with other parts of the brain.
From this image you can clearly see that the amygdala is well positioned to widely influence brain function. Much like the hub of a bicycle wheel.
For this writing assignment check out these two articles for ideas about the function of the amygdala. Summarize what you learned from these readings and then describe how this new knowledge might apply to your own life.