👉 Lithotrites are a type of microtubule that forms when a cell is damaged or injured. They are made up of three separate structures, each with its own function. The smallest structure is called a microtubule itself, which is composed of two shorter tubules connected by a central protein. These tubules contain the actin and myosin filaments that make up the microtubule. The middle section of the microtubule contains the actin