Biology

• Ingestion


  Intake of food
• Digestion


  Breaking down of food so that it can be absorbed by the body
• Absorption


  The process of absorbing food in the form of nutrients into the blood stream of the body
• Assimilation


  The process of nutrients being absorbed by each cell of the body in the form of energy
• Excretion and Egestion


  Secretion of waste, unwanted and excess substances from the body after food the has been digested
• Pancreas


  • Makes digestive juices called enzymes which help to digest food
  • Produces digestive enzymes to digest fats, carbohydrates and proteins
  • Regulates blood sugar by producing insulin
• Liver


  • Directly affects digestion by producing bile
  • Bile helps digest fat
  • Filters out toxins and waste including drugs and alcohol and poisons
  • Stores some nutrients, and releases them into the blood according to the activities and needs of the body (helps the body maintain homeostasis)
• Saliva


  A slightly alkaline secretion of water, mucin, protein, salts, and often a starch-splitting enzyme amylase, (as ptyalin) that is secreted into the mouth by salivary glands, lubricates ingested food, and often begins the breakdown of starches (Maltose)
• Gallbladder


  • Stores bile from the liver, releases it into the small intestine
  • Fatty diets can cause gallstones
  • Bile (enzyme) flows from the gall bladder along the bile duct into the intestine to aid in chemical digestion
• Rectum


  Receives stool from the colon, to let the person know that there is stool to be evacuated, and to hold the stool until evacuation happens
• Anus


  • Lets you know whether the contents are liquid, gas, or solid
  • Surrounded by sphincter muscles that control of movement of stool
• Large Intestine


  • About 1.5 meters long
  • Accepts what small intestines don't absorb
  • Water is absorbed
  • The remains are formed into brown, semi-solid feces, ready to be removed from the body
  • Rectum (short term storage which holds feces before it is expelled)
• Small Intestine


  • Small intestines are roughly 7 meters long
  • Lining of intestine walls has finger-like projections called villi, to increase surface area
  • The villi are covered in microvilli which further increases surface area for absorption
  • Nutrients from the food pass into the bloodstream through the small intestine walls
  • 3 parts- Deudenum, Jejunum, Ilium
  • Secretes digestive enzymes
  • Absorbs 80% ingested water, Vitamins, Minerals, Carbohydrates, Proteins, Lipids
• Stomach


  • J-shaped muscular bag that stores the food you eat, breaks it down into tiny pieces
  • Mixes food with Digestive Juices that contain enzymes to break down Proteins and Lipids
  • Acid (HCI) in the stomach Kills Bacteria
  • Food found in the stomach is called Chyme
• Esophagus


  Function: to take food from mouth to stomach by muscular action called peristalsis
• Epiglottis


  Is a flap-like structure at the back of the throat that closes over the trachea preventing food from entering it. It is located in the Pharynx.
• Mouth


  • Mechanical digestion - Teeth bite off and chew food into a soft pulp that is easy to swallow
  • Chemical digestion - saliva (contains amylase, which helps break down starch)
• Digestive Juices


  • Saliva
  • Gastric juice
  • Pancreatic juice
  • Intestinal juice
• Organs of the Alimentary Canal

  • Mouth
  • Pharynx
  • Esophagus
  • Stomach
  • Small bowel
  • Large bowel
• Accessory Digestive Organs


  • Teeth
  • Tongue
  • Gall bladder
  • Salivary glands
  • Liver
  • Pancreas
• Stages of Digestion


  • Ingestion
  • Digestion
  • Absorption
  • Assimilation
  • Egestion
• Ingestion


  The intake of food into the digestive system
• Digestion


  The process of breaking down food into smaller molecules
• Absorption


  The process of passing the soluble food molecules in the wall of the small intestine through the villi - the tiny, finger-like projections from the epithelial lining of the intestinal wall
• Assimilation


  The process of nutrients being absorbed by each cell of the body in the form of energy
• Egestion


  The release of undigested food collected in the rectum called feces and pushed out of the body through the anus by defecation
• The function of the digestive system is digestion, the breakdown of organic compounds into their simple forms for use by the cells
• Food in mouth


  Food
• Food in Esophagus


  Bolus
• Food in Stomach 


  Chyme
• Food in Large Intestine

  Feces