Download
biology 250 human anatomy n.
Skip this Video
Loading SlideShow in 5 Seconds..
Biology 250: Human Anatomy PowerPoint Presentation
Download Presentation
Biology 250: Human Anatomy

Biology 250: Human Anatomy

218 Views Download Presentation
Download Presentation

Biology 250: Human Anatomy

- - - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript

  1. Biology 250: Human Anatomy Spring 2005 Digestive System

  2. Overview Of Digestive System Alimentary System (Canal) • Also Gastrointestinal (GI) Tract • Continuous muscular digestive tube • Digestion and absorption • Mouth, pharynx, esophagus, stomach, intestines Accessory Digestive System • Contribute to the digestion of food • Teeth, tongue, gallbladder, liver, pancreas

  3. Digestive Processes • Ingestion • Propulsion: peristalsis • Mechanical Digestion: segmentation • Chemical Digestion • Absorption • Defecation

  4. Layers of the Alimentary Canal • Lumen: central canal where food is transported • Mucosa (Mucous Membrane): • Innermost layer; moist epithelial membrane • Secretion, absorption, protection • Submucosa: just external to mucosa • Contains blood vessels, nerve fibers • Gives walls its elastic characteristic

  5. Layers of the Alimentary Canal (Cont.) • Muscularis Externa: external to submucosa • Contains smooth muscle • Inner circular layer, Outer Longitudinal Layer • Responsible for peristalsis & segmentation • Serosa: protective outermost layer • Composed of connective tissue & epithelium

  6. The Mouth • Also called oral cavity, buccal cavity • Oral Orifice: anterior opening • Stratified Squamous Epithelium • Helps to withstand friction forces • Only organ involved with Ingestion

  7. The Lips and Cheeks • Lips (Labia) • Orbicularis Oris Muscle • Red Margin, Labial Frenulum • Cheeks • Buccinators Muscles • The two combined help keep foodbetween teeth, help with speech

  8. The Palate • Forms the roof of the mouth • Hard Palate • Food forced against it by the tongue • Soft Palate • Uvula: prevents food from traveling to the nasal cavity

  9. The Tongue • Occupies the floor of the mouth • Helps to reposition food between teeth • Occupies the taste buds • Intrinsic Muscles • Changes shape of tongue, not position • Extrinsic Muscles • Changes position of tongue, not shape

  10. The Salivary Glands • Produces Saliva Functions of Saliva • Cleanses the mouth • Dissolves food chemicals for taste • Moistens food, aids in bolus formation • Begins chemical digestion of food

  11. The Teeth • Adults contain 32 teeth • 8 incisors, 4 canines, 8 premolars, 12 molars • Crown: portion exposed above gums • Covered by enamel (hardest substance in body) • Root: portion embedded in jaws • Teeth initiate the breakdown of food • Chewing

  12. The Pharynx • Oropharynx, Laryngopharynx • Common passageway for air & food • Contain two layers of skeletal muscle • Inner: Longitudinal Muscle • Outer: Pharyngeal Constrictor Muscles • Muscles propel food into the Esophagus

  13. The Esophagus • Muscular tube; collapsed when no food • Lies posterior to the trachea • Epiglottisdirects food into esophagus • Joins the stomach at the Cardiac Orifice • Gastroesophageal Sphincter • GERD

  14. Mouth, Pharynx, Esophagus • Mastication (Chewing) • Lips, cheeks, tongue keep food between teeth • Deglutition (Swallowing) • Tongue blocks off the mouth • Uvula rises to block of nasopharynx • Larynx rises so allow epiglottis to block off the trachea and the lower airways

  15. The Stomach • Temporary storage tank of food • Coverts food into creamy paste (Chyme) Anatomical Regions of Stomach • Cardiac Region • Gastroesopageal Sphincter • Fundus • Body • Pyloric Region • Pyloric Sphincter • Greater / Lesser Curvatures • Gastric Ulcers

  16. The Small Intestine • Body’s Major Digestive Organ • Digestion completed, absorption occurs Subdivisions of Small Intestine • Duodenum • Jejunum • Ileum

  17. The Liver • Role in digestion is to produce Bile • Helps to break down fat 4 Lobes of the Liver • Right Lobe • Left Lobe • Caudate Lobe • Quadrate Lobe • Hepatitis: inflammation of liver; viral • Six types: A-F

  18. The Gallbladder • Rounded structure, connected to liver • Acts as storage site for bile • Reason for its green color • Gallstones: crystallization of bile • Causes tremendous shooting pain in abdomen • Rx: drugs, lasers, surgery

  19. The Pancreas • Found in the greater curvature of stomach • Aids in the digestion of all foods • Uses pancreatic juices for food digestion

  20. The Large Intestine • Larger diameter than small intestine • Almost half as long as small intestine • Absorbs water, eliminates waste (feces) Large Intestine Subdivisions • Cecum • Appendix • Colon: ascending, transverse, descending, sigmoid • Rectum • Anal Canal