short-term funding markets

In May 2010, the Fed and the European Central Bank reopened the dollar liquidity swap lines following concerns that Greece might default on some of its government bonds. The Fed said that it took this step because of “strains in U.S. dollar short-term funding markets in Europe.”
a. What are “U.S. dollar short-term funding markets in Europe”?
b. How do dollar liquidity swap lines ease strains in these markets?