Answer: The excretory system removes waste from the body. remove waste from the blood. The digestive system breaks down the food you eat into nutrients that provide energy and building materials for cells. The digestive and excretory sytems work together to process the food that you eat. The glands of the endocrine system secrete hormones into the bloodstream to maintain homeostasis and regulate metabolism. The hypothalamus and the pituitary gland are the command and control centers, directing hormones to other glands and throughout the body.