Science

• The foods we eat into their simplest forms: Digestive system

  1. Ingestion

  2. Digestion

  3. Absorption

  4. Assimilation

  5. Egestion/Excretion
• Ingestion

  Process of taking in food
• Digestion

  Process that involves breaking down of large food molecules into smaller molecules
• Absorption

  Process of passing the soluble food molecules in the wall of the small intestine through the villi
• Assimilation

  Movement of digested food nutrients into the blood vessels
• Egestion/Excretion

  Release of undigested food outside the body
• Mechanical Digestion

  Breaks down food into small pieces physically
• Mechanical Digestion

  1. Begins in the mouth as the food is chewed

  2. Occurs from mouth to stomach

  3. Involves teeth, tongue, muscles, etc.

  4. Main actions are chewing and grinding
• Chemical Digestion

  Chemically changes the food into a form that can be used by the cells
• Chemical Digestion

  1. Begins in the mouth when food mixes with saliva

  2. Occurs from mouth to intestine

  3. Involves enzymes, acids, etc.

  4. Main action is hydrolysis by enzymes
• Mouth

  The first chamber of the digestive system (also known as oral cavity)
• Tongue

  Manipulates the food during chewing and forms into a mass called bolus. It pushes the food into the pharynx.
• Teeth

  Break up the food by both biting and chewed
• Teeth

  • Milk teeth: 20
  • Permanent teeth: 32
• Stomach

  A stretchy bag that holds your food after you eat. It is a muscular sac with thick and expandable walls.
• Esophagus

  The tube that connects your mouth and your stomach
• Salivary glands

  Glands that produce saliva
• About 1 liter of saliva is secreted by these glands
• Saliva

  Mixture of serous and mucous fluids that contains enzymes. It wets the chewed, partially digested food called bolus to facilitate swallowing.
• Epiglottis

  A leaf-shaped flap in the throat that prevents food and water from entering the trachea and the lungs
• Pharynx

  It is mainly involved in the passage of chewed/crushed food from the mouth through the oesophagus. It is a y-shaped tube attached to the terminal end of the mouth.
• Chyme

  After about 3-4 hours in the stomach, food is reduced to a thin, soupy liquid
• Large Intestine

  Tube that is 6 cm wide and 1.5 m long. It gets waste from small intestine.
• Appendix

  A small pouch that is located in our right abdomen where the small intestine meets the large intestine
• Rectum

  Is about 15 cm long. It connects the colon to the anus. It serves as a warehouse or storage for the undigested food or feces/stool.
• Defecation


  Process of expulsion of the feces
• Accessory organs

  Organs which participate in the digestion process but are not actually a part of GIT
• Liver

  Is the largest gland of the body. It aids digestion by producing bile.
• Gallbladder

  Located under your liver. It is a storage tank for bile (a greenish-yellow liquid) that helps your body break down and use fats.
• Meiosis

  Sexual reproduction. The form of cell division by which gametes, with half the number of chromosomes, are produced.
• Gametes

  Sex cells that divide to produce sperm or egg
• Spermatogenesis


  Male: Production of sperm
• Oogenesis


  Female: Production of egg or ova
• Meiosis


  Cell division that reduces the chromosome number by one-half.
• Pancreas


  Releases digestive enzymes to complete the process of chemical digestion
• Large Intestine


  Waste stays for 18 hours to 2 days
• Pancreas


  Is a large yellowish gland that is present just behind the stomach
• Rectum


  It connects the colon to the anus
• Small Intestine


  Food stays for 3 to 5 hours
• Pancreas


  It produces hormones (insulin) responsible for controlling the level of glucose in the blood