digestive system

• Gastrointestinal tract - direct link/path between organs
• digestive system structure

  • Mouth
  • esophagus
  • stomach
  • small intestine
  • large intestine
  • rectum
• The oral cavity/mouth - serves as the entrance of the digestive system.
• teeth - is responsible for the mastication of food.
• The oral cavity is composed of:

  • teeth
  • tongue
  • salivary glands
• the three parts of the teeth:

  • crown
  • neck
  • root
• tongue - Your tongue is a long, muscular structure that perceive taste and helps mix food with saliva.
• The rough parts of the tongue is the papillae, where the taste buds are found.
• Pharynx (throat) - connects the mouth to the esophagus and larynx.
• Salivary Glands - secretes saliva which contains enzymes to begin the process of digestion.
• small intestine - site of most nutrient absorption; divided into duodenum, jejunum, and ileum.
• Small Intestine - absorbs nutrients from digested food.
• Gallbladder - stores bile produced by liver until needed.
• large intestine - absorbs water from undigested material; consists of cecum, colon, rectum, and anus.
• Liver - largest gland in the body; produces bile, stores glucose as glycogen, detoxifies blood, synthesizes proteins, and regulates metabolism.
• Large Intestine - reabsorbs water and electrolytes from undigested material.
• Rectum - stores feces until it's eliminated through anus.
• Anus - opening at the end of the large intestine.
• Pancreas - releases hormones such as insulin and glucagon to regulate blood sugar levels.
• Esophageal sphincter - Part of pharynx which prevents food from entering the

  trachea.
• epiglottis - Found between the esophagus and the stomach, it prevents the backward flow of food from

  stomach to esophagus.
• peristalsis - The wavelike motion of the muscles of the esophagus which push

  the food down.
• 3 - How many layers of muscle does the stomach have?
• hydrochloric acid - What acid is included in the gastric juice which digest food and kill bacteria.
• chyme - the term used when the digested food is mixed with the

  stomach acid
• three partition of the small

  intestine

  • duodenum
  • jejenum
  • ileum
• reabsorption/water and salt are added - happens when the undigested food reach the large

  intestine
• glands that helps the digestive

  system in digesting food.

  • salivary gland
  • liver
  • pancreas
  • intestinal gland
  • mucous gland
  • stomach glands
• organs without function/lost its function - Appendix is a vestigial organ. What does vestigial organ

  mean?
• mechanical digestion - food is broken down by mechanical means, eg. teeth and stomach. (it happens in the mouth)
• chemical digestion - the breakdown of large molecules into smaller molecules by chemical reactions

  happens in the (mouth, stomach, and small intestine)
• intracellular digestion - happens in the cell
• extracellular digestion - happens outside the cell but inside the system
• Enzymes - are special protein molecules that acts as catalyst that speed up the chemical reaction.
• pepsin - a protease that breaks down proteins into amino acids ( an enzyme found in the stomach, rennin in infants)
• Pepsin - breaks down other protein into amino acids and

  peptides.
• Food in the stomach mix with

  gastric juice is called Chyme.
• Rennin digest milk proteins.
• Lipase - breaks down fat

  doplets (from liver)

  completely digesting it.
• Protease/Trypsinogen/

  Chymotrypsinogen - break down protein into

  amino acids and peptides