What causes the accumulation of fluids in tissues and how does this fluid become lymph?

At one point or another we have all bumped our heads, stubbed our toes or had a mosquito bite. We all know the result which is swelling or inflammation. Using the medical terminology that you’ve learned this week discussed the following questions.

What causes the accumulation of fluids in tissues and how does this fluid become lymph?

The initial discussion post must be at least 250 words of content, referencing the reading of the week, and include a scholarly source.