DIGESTIVE SYSTEM

• Digestive System


  Is like a big juicer of food that processes important materials needed for the function of the body
• Main purpose of Digestive System

  Grind and juice out our food and get its nutrients so that it can be used as a fuel of cell in our body
• 2 main processes of Digestion

  • Mechanical digestion
  • Chemical digestion
• Mechanical digestion


  Is the process in which food is broken down by means of chewing, biting and grinding to make it into smaller particles
• Chemical digestion


  Is the process of digesting food with the use of enzymes to make food soluble for it to be absorbed by the body and be transferred through the circulatory system
• Four stages of food processing

  • Ingestion - taking in food that starts in the mouth
  • Digestion - breaking down of food into smaller particles in order to use its nutrients
  • Absorption - taking the nutrients from the digested food to be used by the body for different life processes
  • Egestion - removing any leftover wastes after the digestion process
• Parts of the Alimentary Canal

  • Mouth
  • Esophagus
  • Stomach
  • Small intestine
  • Large intestine
  • Rectum
  • Anus
• Saliva


  Contains ptayalin, a.k.a salivary amylase, which softens and converts the starch in the food we eat into a simple sugar called maltose while chewing
• Pharynx


  Found at the region of the neck
• Bolus


  Function as a passageway of the ball of food mixed with saliva
• 3 main divisions of pharynx

  • Nasopharynx - near in the nasal cavity
  • Oropharynx - area of oral cavity
  • Hypopharynx - lowest part of the pharynx near the esophagus
• Esophagus


  A long, muscular tube that functions as a passageway of food from the pharynx to the stomach with the use of peristalsis
• Peristalsis


  Is a wave of muscular contractions that push the masticated food (bolus) down towards the stomach
• Stomach


  Is a J-shaped muscular bag where the food goes to be chemically digested
• Cardiac sphincter


  Is an opening in the stomach that allows the food to get inside the esophagus and closes to prevent backflow of food and digestive enzymes
• Foods stay to the stomach


  For 6 hours where it is being thoroughly digested until it becomes chyme
• Chyme


  Semisolid form of digested food
• Small intestine


  20-30 feet long small intestine
• Jejunum


  The longest part of the small intestine
• Villi


  Nutrients are mainly absorbed with the tiny hair like projections in the intestinal wall
• Large intestine


  • Cecum
  • Ascending colon
  • Transverse colon
  • Descending colon
  • Sigmoid colon
• Mucus


  Is also present in the large intestine to lubricate the food as it goes to the rectum and to the anus
• Rectum and Anus


  The waste product or feces from the large intestine is then temporarily stored to the rectum before it will be expelled by the anus. The rectum expands until it becomes full which then tells the brain to release it out with the use of the nerves in the rectum. This is called as bowel movement.
• Accessory Organs


  • Salivary glands
  • Liver
  • Gallbladder
  • Pancreas
• Salivary Gland


  These are glands that produce saliva used for softening the food and breaking down carbohydrates into simple sugar
• Liver


  Found below the right side of the ribs. Main Functions: Produce bile, which breaks down or emulsify fat during digestion. Also detoxifies the blood as it circulates the body such as alcohol.
• Gall Bladder


  Is a small sac located under the liver. Store bile- main purpose
• Pancreas


  Is a bumpy, leaf-shaped organ located below the stomach. It contains pancreatic duct, a tube that is located at the duodenum of the small intestine.
• Swallowing involves the movement of food through the pharynx (throat) to the esophagus (food pipe), where it travels by peristalsis (muscular contractions).