Undulating membrane is found in the following organisms: In some parasitic flagellates such as trypanosomes and trichomonads, undulating membrane is a fin-like extension usually associated with the flagellum. The presence of undulating membrane enhances motility of the parasite in a viscous fluid, such as blood.

What is an undulating membrane?

Medical Definition of undulating membrane

: a vibratile cytoplasmic membrane: a : a lateral expansion of the plasma membrane in some flagellates that is usually associated with a flagellum. b : a row of laterally fused long cilia associated in many ciliates with the oral structures.

How is undulating membrane formed?

The flagellum emerges from the posterior end and folds back along the parasite's body. This attachment of the flagellum to the body forms an undulating membrane (um) that spans the entire length of the parasite and the free flagellum emerges from the anterior end.