The digestive system is responsible for breaking down food into absorbable nutrients and eliminating solid waste. It consists of the gastrointestinal tract (mouth, esophagus, stomach, intestines, anus) and accessory organs (liver, pancreas, gallbladder). Through mechanical and chemical digestion, it processes food, absorbs water, electrolytes, vitamins, and macronutrients (carbohydrates, proteins, fats), and transports indigestible matter for excretion, providing the body with essential energy and building blocks.