Uvula vesicae seen in bladder is formed from the following structure:

Uvula vesicae is a small elevation situated immediately behind the urethral orifice, which is produced by the underlying median lobe of the prostate. It enlarges with age due to enlargement of the underlying median lobe of the prostate and may inhibit complete bladder emptying. Ref: Clinical Anatomy by Regions By Richard S. Snell, 2011, Page 272.