Unit 2: Internal Systems Components of The Digestive System I

Components of the Digestive System Molars (12) Premolars or bicuspids(8) Canines (4) Incisors (8) Homework take-up Teeth:

Components of the Digestive System Tongue: Different parts of the tongue are able to taste one of four basic tastes. sour bitter salty sweet

Components of the Digestive System Kinds of TeethDescriptionFunction  long & pointy  sharp  rip/tear  very developed in predators  wide, but very thin  bumps on bottom edges  cut like knives for biting  flat & broad  have 2 bumps on surfaces called cusps (bicuspids)  grinding & mashing  flat & broad  have 4 cusps  grinding & mashing Canines Incisors Premolars Molars

Components of the Digestive System periodontal membrane enamel pulp (cavity) root canal nerve artery vein dentin crown (above gums) gingiva (gums) root (under gums) nerve endings

Components of the Digestive System Mouth i. Teeth: enamel: contains calcium makes it the hardest substance in the body caries: tooth decay in enamel (cavity) caused by: dentin: bone-like substance surrounding pulp pulp cavity: contains nerves & blood vessels i)acids produced by bacteria ii)grinding dentin pulp (cavity) enamel root canal) caries

Components of the Digestive System Teeth:(continued) pulpitis: tooth ache caused by inflammation of the pulp gingivitis: inflammation of the gums results in periodontal disease plaque: sticky film of bacteria & food between gums & teeth removed by flossing root canal: dentist removes infected pulp & sterilizes tooth keeps tooth alive

Components of the Digestive System OrganCommentsFunction 1.Mouth opening to digestive system a)Teethdifferent shapes for tearing & grinding ingestion physical digestion

Components of the Digestive System OrganCommentsFunction b) saliva made by 3 pairs of salivary glands secrete saliva into oral cavity contains: 1.water: 2.mucus: 3.salivary amylase: lubricates food (makes it slippery) to dissolve food enzyme which digests starch i.e. into mono & disaccharides Parotid gland Submandibular gland Sublingual gland

Components of the Digestive System OrganCommentsFunction c) tongue very strong muscle contains large numbers of taste buds bolus: 2. physical digestion: chewing & mixing food with saliva 1.sensory: taste & temperature control 3. swallowing: a.pushes bolus up & to the back of the pharynx nerve endings. ball of chewed food b.causes epiglottis to block trachea 4. speech

Components of the Digestive System OrganCommentsFunction d) epiglottis 2) pharynx flap of tissue at the base of the tongue above the trachea back of the throat prevents food from going into lungs (down windpipe) to avoid choking. common passageway for food & air

Components of the Digestive System OrganCommentsFunction 3) esophagus narrow tube about 30 cm long connecting pharynx to stomach contains 2 muscle layers which relax and contract rhythmically for peristalsis. 1. leads food into stomach 2. ensures that food (bolus) is pushed into stomach (mucus glands help lubricate the bolus) wave-like contractions produced by circular & longitudinal muscles

Components of the Digestive System

OrganCommentsFunction 4) cardiac sphincter 5) pyloric sphincter at the entrance of the stomach at the end of the stomach. closes during digestion to prevent backflow of gastric juice into esophagus *sphincters: rings of muscles (open/close) closes during digestion to keep chyme (semi- digested food) in stomach(2-3 hrs) pyloric sphincter cardiac sphincter heartburn: pain from splashing of gastric acid into the esophagus opens to allow chyme to enter small intestine

Components of the Digestive System OrganCommentsFunction 6) stomach glands in lining make gastric juice containing: tough muscular bag (j-shaped) lined with 3 layers of muscles to churn & mix food with gastric juice ulcer: chyme:. 1.hydrochloric acid: a)physical digestion of fibrous tissue b)kills bacteria c)dissolves minerals d)converts pepsinogen into pepsin (active) 2. pepsin: enzyme which breaks down proteins into amino acids 3. mucus: thick layer to protect stomach wall from acid & pepsin wound in the stomach lining due to high acidity & low mucus semi-digested food (very acidic)

Components of the Digestive System cardiac sphincter pyloric sphincter duodenum circular muscles oblique muscles longitudinal muscles

Components of the Digestive System glands in stomach lining ulcer in stomach lining

ENDOSCOPE VIDEOS ACID REFLUX GASTRIC FOLDSSTOMACH LINING & GASTRIC JUICE

ENDOSCOPE VIDEOS STOMACH ULCER MULTIPLE STOMACH ULCERS

Homework Page 212 Questions # 1-3 Page 214 Questions # 1-2,4-6 Page 216 Questions # 1-3