Digestion: Process of changing complex solid foods into simpler soluble forms which can be absorbed by the body
Enzymes: Chemical substances that promote chemical reactions in living things although they themselves are unaffected by the reactions
Alimentary Canal: Digestive Tract or Gastrointestinal (GI Tract) consists of a mouth (Oral Cavity), Pharynx (Throat), Esophagus (Gullet), Stomach, Small Intestine, Large Intestine (Colon), and the Anus
30 Feet in Length(Slimy Mucus Lubricates and Insulates the GI Tract)
Accessory Organs: Tongue, Teeth, Salivary Glands, Pancreas, Liver, and Gall Bladder
4 Layers of the Digestive System
Mucosa: Innermost Lining made up of Epithelial Cells
Change Food chemically to end products of fats, carbohydrates, and proteins
Absorbs Nutrients into the Blood Stream Capillaries of the Small Intestines for use in the body
Eliminate Waste Products of Digestion
Mouth: (Oral or Buccal Cavity) Lips: (Labia) Protects the Opening of the mouth. Roof has a hard and soft palate. Hard Palate is part of the Maxillary and Palatine Bones. Soft Palate is made from a moveable mucous membrane. Soft Palate separates the mouth from the nasopharynx
Uvula: Prevents food from entering the Nasal Cavity when Swallowing
Tongue: Attached to Four Bones (Hyoid, Mandible, Two Temporal Bones)
Small Intestine: Main absorption of food. Breaks down Protein using pepsin. It secretes digestive juices and is covered with villi, which absorbs the end product of digestion. Absorption is possible because of Villi. Each Villus contains a network of blood and lymph capillaries that absorbs nutrients. The Small Intestine has 3 parts.
Duodenum: 12 inches and curves around the pancreas. Bile and
Pancreatic juices enter here and break down and emulsify fats. Pancreatic juices mainly Protease or Trysin breaks down protein to Ammino Acids. Amylase or Amylopsin which are secreated in the mouth continue to break down starches and carbohydrates into glucose. Lipase or Steapsin break down fats to fatty acids and glycerol. Pancreatic Juices also contains sodium bicarbonate which neutralizes the food content.
Jejunum: 8 - 12 feet long
Ileum: 10 – 15 feet long (Longest of the sections).
Pancreas: Feather shaped organ located behind the stomach. It is both an Exocrine and Endocrine gland
Exocrine Gland means it has a duct that carries away its secretions
Endocrine Gland means it is ductless and the secretions are emptied directly into the bloodstream.
Liver: Largest organ in the body, located below the diaphragm. The Portal Vein carries products of digestion from the small intestine to the liver.
Manufactures Bile (Yellowish green digestive juices)
Common Bile duct (Hepatic duct from the liver joins the Cystic Duct from the Gall Bladder) If this duct is blocked then Jaundice occurs which gives the skin and sclera of the eyes a yellow color.
Salivary Amylase and Ptyalin converts starches and carbohydrates into simple sugars. Saliva is affected by the nervous system. Just thinking about food causes the mouth to water or dry mouth occurs when you are nervous or frightened.