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Download Digestive System - Blue Valley Schools
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Digestive System Functions of the digestive system • Ingest food, break food down mechanically, and break down food chemically. • Absorb nutrients into blood stream • Rid the body of indigestible remains (defecate) Alimentary canal • • • • • Mouth Pharynx Esophagus Stomach Small Intestine (Duodenum, jejunum, and ileum) • Large Intestine (Cecum, Colon, Rectum, and Anus) Accessory structures adding to Alimentary Canal • • • • • Parotid gland Submandibular gland Sublingual gland Liver Pancreas Lips • Lips are temperature receptors • Lips are so red, because of large numbers of blood vessels Palate • Hard palate is most anterior, and is formed by the maxillae and palatine bones • Soft palate forms the posterior portion of the roof of the mouth. Uvula hangs from the soft palate, and is a muscular structure to help trigger the swallowing process. Tongue • Composed of skeletal muscle. • Frenulum anchors the tongue to the floor of the mouth • Helps form food into a bolus • Contains taste buds • Tongue secretes small amounts of lingual lipase, which initiates digestion of lipids Salivary glands • Parotid- largest salivary gland. Rich in serous cells, which secrete amylase. Secretion enters the mouth via the parotid duct. (para=near, otia=ear) • Sublingual- Rich in mucosa cells, which secrete mucus. This gland is under the tongue • Submandibular- Has both serous and mucosa cells. Teeth • Three parts to a tooth, crown, neck and root • Gums, are called gingiva • Tooth is primarily composed of dentin. Dentin covers the pulp cavity. Extensions in the pulp are called root canals. • Root canals have blood vessels and nerves • Enamel, covers the dentin, and is the hardest substance in the body Specialist • Dentist- deals with the everyday cleaning and care of teeth • Endodontics- treatment of diseases that effect the pulp, root, periodontal ligament, and alveolar bone. • Orthodontics- is concerned with the prevention and correction of abnormally aligned teeth Tonsils • Palatine tonsils have lymphatic tissue, thus they help fight infections as do all lymphatic tissue in the body, by bathing tissues Pharynx • Nasopharynx • Oropharynx • Laryngopharynx Esophagus vs Trachea • Esophagus – a muscular tube allowing food to pass from the pharynx to the stomach….aided by peristalsis…. Collapsed when not in use • Trachea- Hollow tube running from pharynx to lungs. Held open by rings of hyaline cartilage, as you are always breathing
