How cholesterol contributes to membrane fluidity and structure?

Cholesterol, the major sterol in animal tissues, is amphipathic, with a polar head group (the hydroxyl group at C-3) and a non- polar hydrocarbon body (the steroid nucleus and the hydrocarbon side chain at C-17) It lies alongside the phospholipids in the membrane and tends to dampen the effects of temperature on the membrane. Thus, cholesterol functions as a buffer, preventing lower temperatures from inhibiting fluidity and preventing higher temperatures from increasing fluidity too much.