Digestive System and Nutrition in Humans



  • Food is vital for all living organisms, providing essential components for survival. 
  • Major components include carbohydrates, proteins, and fats, alongside vitamins and minerals in smaller quantities. 
  • Food serves the purpose of providing energy and organic materials for growth and tissue repair. 
  • Water is crucial for metabolic processes and prevents dehydration in the body. 
  • Biomacromolecules in food cannot be directly utilized by the body and require breakdown. 
  • Digestion is the process of converting complex food substances into simpler, absorbable forms. 
  • This process occurs in the digestive system through mechanical and biochemical methods. 
  • Physical breakdown of food into smaller particles for easier digestion. 
  • Examples include chewing in the mouth and churning in the stomach. 
  • Chemical breakdown of food molecules into simpler forms through enzymes. 
  • Enzymes play a crucial role in breaking down carbohydrates, proteins, and fats into absorbable forms. 
  • After digestion, nutrients are absorbed into the bloodstream through the walls of the small intestine. 
  • Nutrients are then transported to various parts of the body for utilization.