Digestive system

• Organs- Mouth, esophagus, stomach, liver, gallbladder, pancreas, large intestine, small intestine, rectum, anus
• Function of digestive system

  • The main function of the digestive system is digestion. It breaks down food into their simplest forms for use by the cells
  • The digestion is the chief function of the digestive system. it breaks down food mechanically and chemicall
  • the journey of the food from the mouth to the anus is 18-20 hours
• Ingestion

  • The first process in the digestive system
  • Starts in the mouth
• Digestion

  • The second process in the digestive system
  • It involves in breaking down large food particles into smaller particles for easy absorption of cells
  • chemical and mechanical digestion begins in the mouth`
  • While the food enters the mouth, the teeth cut, crush, and breaks the food into tiny pieces while the tongue helps mix the food with saliva secreted from the salivary glands forming into a moist ball called bolus so that it can be easily swallowed
• Chewing

  • Also known as mastication.
  • Considered as the mechanical digestion which is the initial stage of digestion
• Saliva

  • Contains salivary amylase, the enzyme that breaks down starch into smaller carbohydrates
• Esophagus- The tube that attaches the mouth to the stomach
• Peristalsis: A series of wave like contractions that push and transports food and liquid in small sections to the stomach
• Stomach

  • Is a J shaped, bag like muscular organ that stores approximately 1 liter of fluid and blood
  • Its function is to store food. which turns into chyme after being acted on by the stomach acid
• Chyme: it is the semi-liquid mixture from partly digested food and enzyme in the stomach.
• Gastric juices

  1. Hydrochloric acid
  2. Pepsin
• Small intestine: Breaks down food further into substances such as glucose, that can be absorbed by the villi
• Absorption: It is the process of passing the soluble food molecules in the walls of the small intestine through the villi. It is the third process in the digestive system
• Villi

  1. The tiny finger-like projections of the epithelial lining of the intestinal wall
  2. Each villus contains blood capillaries that enable it to absorb substances
  3. Villus is the plural form
• Assimilation

  • It is the movement of digested food nutrients into the blood vessels of the small intestine through diffusion and the use of nutrients into the body cells through the microvilli (microscopic cellular membrane projection)
• Large intestine

  • Is where the reabsorption of liquid, electrolytes, and some vitamins of undigested food takes place
  • It is the last segment of the gastrointestinal tract that completes absorption and compacts waste
• Egestion

  • It is the release of undigested food collected in the rectum called feces and is pushed out of the body through the anus by defecation
• Gallbladder

  • A peach shaped sac that can hold about 50ml of bile
  • it produces bile
• Liver: The largest organ in the body and has a mass of 2 kilograms
• Pancreas

  • Makes three different kinds of enzymes namely the amylase, peptidase, and lipase released into the pancreatic duct that aid in the digestion of the three organic compounds such as carbohydrates, protein, and fats respectively
  • This process takes about a half of a liter of digestive juices each day.