Could someone please be so kind to help me to understand the landing process of ETHLend (LEND)?

How are the loans via ETHLend (LEND) secured.  If secured by other crypto asset how do they manage price fluctuation between loan and security asset? (I assume they are not in business of handing out unsecured loans)

I have to admit this project is not in my alley, only wondering about the basic principles. Came across this project  several weeks ago but passed.