Do win streaks affect mmr gains?

When I was 8 wins 7 losses I was at silver II with 67 LP. Then I played a lot within that approximate range, recently had a long tilt and went down to like 50 losses and 40 wins. Just came back to 55 wins and 55 losses with a huge win streak with few interruptions and im at promos to silver I. How does my win streak / loss streak affect my mmr? Do win streaks place u at a higher mmr than ur league so u gain more lp per win and less per loss if u keep it up?