Cells provide structure for the body, take in nutrients from food, convert those nutrients into energy, and carry out specialized functions. Cells have many parts, each with a different function. Some of these parts, called organelles, are specialized structures that perform certain tasks within the cell. During mitosis, cells build a molecular machine, which is known as the mitotic spindle. After food is changed to waste, it is pushed out of your body in a bowel movement. The stomach breaks down food into a liquid mixture. The small intestine absorbs nutrients from the liquid mixture. The colon absorbs water from the liquid waste, converting it into solid waste (stool). After you workout, your body repairs or replaces damaged muscle fibers through a cellular process where it fuses muscle fibers together to form new muscle protein strands or myofibrils. These repaired myofibrils increase in thickness and number to create muscle hypertrophy (growth).