SCIENCE -

• Why do we need food?

  The main nutrients the body needs are:

  Carbohydrates for energy

  Proteins for growth and repair

  Fats to store energy

  Vitamins and minerals to keep the body healthy.
• Digestive System


  A long tube where the food is broken down into nutrients.
• Digestive System


  • Divided into:

  Alimentary Canal

  Accessory organs
• Alimentary Canal


  Also called the digestive tract or gastrointestinal (GI) tract.

  This long tube of organs makes a pathway for food to travel through the body. It runs from the mouth to the anus.
• Organs of the Alimentary Canal

  • Mouth, esophagus, stomach, small intestine, large intestine, anus
• Accessory Organs


  Organs that help the process by adding enzymes and chemicals to break down the food.
• Important Accessory Organs


  • Salivary glands, liver, gallbladder, pancreas
• Digestion


  The mechanical and chemical breakdown of foods into small organic fragments.

  Begins in the mouth and finishes in the small intestine.
• Mechanical Digestion


  The food is broken down into smaller pieces through chewing - teeth bite, chew, grind food into something we can swallow.
• Chemical Digestion


  Uses enzymes to break down food. The enzyme found in saliva, salivary amylase, starts the chemical digestion of starch.
• Five Stages of Digestion

  • Ingestion

  2. Digestion

  3. Absorption

  4. Assimilation

  5. Egestion
• Ingestion


  The process by which food is taken into the mouth.
• Digestion


  The process by which ingested food is broken down into smaller particles.
• Absorption


  The process of absorbing nutrients into the bloodstream and transported to cells.

  Mainly located in small intestine, some in stomach, and large intestine.
• Assimilation


  The process by which absorbed nutrients from the digested food are used by the cells.
• Egestion


  The process through which undigested food is now expelled or removed from the body as feces.
• Eating in moderation allows the digestive organs to function optimally, promoting better nutrient absorption and overall digestive health.
• Mouth


  The start of the digestive system. Helps break down food which helps the food to be digested in the body.
• Mouth


  Produces saliva which breaks down the chemicals in the food a bit, which helps make the food mushy and easy to swallow.
• Salivary Glands


  Produce saliva, which keeps the mouth and other parts of the digestive system moist.
• Esophagus


  A long, thin, and muscular tube that connects the pharynx (throat) to the stomach. It secretes mucus.

  Food and fluids are propelled through the esophagus into the stomach using waves of muscle contractions called peristalsis.
• Stomach


  A muscular sac that lies between the esophagus and the small intestine in the upper abdomen.

  The stomach releases acids and enzymes for the chemical breakdown of food. It can also expand to temporarily store food.

  By the time food is ready to leave the stomach, it has been turned into a thick liquid called chyme.
• Small Intestine


  Absorbs about 90% of the nutrients from the food we eat.

  Digested food passes through the wall of the intestine into the blood vessels which then distribute the nutrition first to the liver and then through the rest of the body.
• Parts of the Small Intestine

  • Duodenum - the C-shaped first part

  Jejunum - the coiled midsection

  Ileum - the final section that leads into the large intestine
• Liver


  A large, meaty organ that removes toxins from the body's blood supply and maintains healthy blood sugar levels. The liver also produces bile, a fluid that helps digest fats and carry away waste.
• Pancreas


  Part of the digestive system and produces important enzymes and hormones that help break down foods.

  Enzymes, or digestive juices, produced by the pancreas are secreted into the small intestine to further break down food after it has left the stomach.
• Gallbladder


  A small storage organ located under the liver. Holds bile produced in the liver until it is needed for digesting fatty foods in the duodenum of the small intestine.
• Large Intestine


  Performs the vital task of absorbing water and vitamins while converting digested food into waste (feces).
• Parts of the Large Intestine

  • Cecum - the beginning of the large intestine. The appendix is a small, hollow, finger-like pouch that hangs off the end of the cecum.

  Colon - extends from the cecum up the right side of the abdomen (the ascending colon), across the upper abdomen (transverse colon), and down the left side of the abdomen (descending colon).

  Rectum - where poop is stored until it leaves the digestive system through the anus as a bowel movement.
• Anus


  The opening at the far end of the digestive tract through which stool leaves the body.

  Acts like a gate that allows the waste to exit the body.