DIGESTIVE SYSTEMS

• Digestive System

  • The separate organs in the digestive system all work together to perform the vital function of digesting food, absorbing nutrients and eliminating waste

  • Nutrients are substances that are essential for life and growth
  • Is defined as breaking up large insoluble molecules into small soluble ones.
  • It can be done mechanically, e.g. chewing
  • Or chemically, with digestive chemicals called enzymes e.g. The enzyme amylase in your saliva digests starch into simple sugars
  • Once nutrients are digested, they travel around the body in blood
• The Mouth

  • The mouth both mechanically and chemically digests food
  • Different enzymes digest different nutrients
  • Amylase digests starch
  • Pepsin digests protein
  • Lipase digests fat
• Swallowing

  • Your chewed-up food is called BOLUS.
  • It is swallowed down your food pipe, or oesophagus.
  • The muscles squeeze the bolus down, this is called peristalsis.
• Stomach

  The food, once chewed, reaches your stomach. There, it is mixed with strong hydrochloric acid, which kills germs, and pepsin enzymes that digest protein. The stomach churns to ensure that the chewed food, also known as bolus, is properly mixed with these digestive juices. After this process, it is referred to as Ghyme.
• Small Intestine

  • The small intestine is where most digestion and absorption of nutrients occurs.
  • Accessory organs like the liver and pancreas make more digestive chemicals that digest the nutrients in the chyme.
  • The small intestine has folds (villi) that have folds (microvilli), this increases the surface area.
  • Maximum amounts of nutrients can be absorbed into the blood and sent to the liver for processing.
  • The small intestine is 5-7 Metres long.
• The large intestine is much wider than the small intestine. Its role is to remove water from the remnants of the digestive system after digestion and absorption, which results in feces(poo). The large intestine has many folds to increase its surface area. The feces are held temporarily in the rectum before being expelled out of the body through your bottom.
• villi are tiny, finger-like projections made up of cells that line the entire length of your small intestine. Villi absorb nutrients from the food eaten when it passes through the small intestine.