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Ch 14 Dig Sys A

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Ch 14 Dig Sys A

  1. 1. Chapter 14 The Digestive System and Body Metabolism
  2. 2. <ul><li>Digestive System & Body Metabolism </li></ul><ul><li>Digestion </li></ul><ul><ul><li>Breakdown of ingested food </li></ul></ul><ul><ul><li>Absorption of nutrients into the blood </li></ul></ul><ul><li>Metabolism </li></ul><ul><ul><li>Production of cellular energy (ATP) </li></ul></ul><ul><ul><li>Constructive and degradative activities </li></ul></ul>
  3. 3. <ul><li>Organs of the Digestive System </li></ul><ul><li>Two main groups </li></ul><ul><ul><li>Alimentary canal – continuous hollow tube </li></ul></ul><ul><ul><li>Accessory digestive organs </li></ul></ul>
  4. 4. <ul><li>Organs of the Alimentary Canal </li></ul><ul><li>Mouth </li></ul><ul><li>Pharynx </li></ul><ul><li>Esophagus </li></ul><ul><li>Stomach </li></ul><ul><li>Small intestine </li></ul><ul><li>Large intestine </li></ul><ul><li>Anus </li></ul>
  5. 7. <ul><li>Mouth (Oral Cavity) Anatomy </li></ul><ul><li>Lips (labia) – protect the anterior opening </li></ul><ul><li>Cheeks – form the lateral walls </li></ul><ul><li>Hard palate – forms the anterior roof </li></ul><ul><li>Soft palate – forms the posterior roof </li></ul><ul><li>Uvula – fleshy projection of the soft palate </li></ul>Figure 14.2a
  6. 8. <ul><li>Mouth (Oral Cavity) Anatomy </li></ul><ul><li>Tongue – attached at hyoid and styloid processes of the skull </li></ul>
  7. 9. <ul><li>Mouth (Oral Cavity) Anatomy </li></ul><ul><li>Tonsils </li></ul><ul><ul><li>Palatine tonsils </li></ul></ul><ul><ul><li>Lingual tonsil </li></ul></ul>Figure 14.2a
  8. 10. <ul><li>Processes of the Mouth </li></ul><ul><li>Mastication (chewing) of food </li></ul><ul><li>Mixing masticated food with saliva </li></ul><ul><li>Initiation of swallowing by the tongue </li></ul><ul><li>Allowing for the sense of taste </li></ul>
  9. 11. <ul><li>Pharynx Function </li></ul><ul><li>Passageway for air and food </li></ul><ul><li>Food propelled by 2 muscle layers </li></ul><ul><ul><li>Longitudinal inner layer </li></ul></ul><ul><ul><li>Circular outer layer </li></ul></ul><ul><ul><li>Peristalsis - movement by alternating contractions of the muscle layers </li></ul></ul>
  10. 12. <ul><li>Esophagus </li></ul><ul><li>pharynx to stomach through diaphragm </li></ul><ul><li>Conducts food by peristalsis (slow rhythmic squeezing) </li></ul><ul><li>Passageway for food only </li></ul>
  11. 13. <ul><li>Stomach Anatomy </li></ul><ul><li>left side of the abdomen </li></ul><ul><li>Food enters at cardioesophageal sphincter </li></ul><ul><li>Regions </li></ul><ul><ul><li>Cardiac region – near the heart </li></ul></ul><ul><ul><li>Fundus </li></ul></ul><ul><ul><li>Body </li></ul></ul><ul><ul><li>Pylorus – funnel-shaped terminal end </li></ul></ul><ul><li>Food empties into the small intestine at the pyloric sphincter </li></ul><ul><li>Rugae – internal folds of the mucosa </li></ul>
  12. 14. <ul><li>Stomach Functions </li></ul><ul><li>Acts as a storage tank for food </li></ul><ul><li>Site of food physical breakdown </li></ul><ul><li>Chemical breakdown of protein begins </li></ul><ul><li>Delivers chyme (processed food) to the small intestine </li></ul>
  13. 15. <ul><li>Specialized Mucosa of the Stomach </li></ul><ul><li>Gastric glands – secrete gastric juice </li></ul><ul><li>Chief cells – produce protein-digesting enzymes (pepsinogens) </li></ul><ul><li>Parietal cells – produce hydrochloric acid </li></ul><ul><li>Endocrine cells – produce gastrin </li></ul>
  14. 17. <ul><li>Small Intestine </li></ul><ul><li>major digestive organ </li></ul><ul><li>nutrient absorption </li></ul><ul><li>Suspended from abdominal wall by mesentery </li></ul><ul><li>3 parts: </li></ul><ul><ul><li>Duodenum - curves around pancreas </li></ul></ul><ul><ul><li>Jejunum </li></ul></ul><ul><ul><li>Ileum </li></ul></ul>
  15. 18. <ul><li>Chemical Digestion in the Small Intestine </li></ul><ul><li>Source of enzymes that are mixed with chyme </li></ul><ul><ul><li>Intestinal cells </li></ul></ul><ul><ul><li>Pancreas </li></ul></ul><ul><li>Bile enters from the gall bladder </li></ul>
  16. 20. <ul><li>Villi of Sm. Intestine </li></ul><ul><li>Fingerlike structures formed by mucosa </li></ul><ul><li>Give intestine more surface area </li></ul>Microvilli of Sm. Intestine <ul><li>Small projections of plasma membrane </li></ul><ul><li>Found on absorptive cells </li></ul>
  17. 21. <ul><li>Structures Involved in Absorption </li></ul><ul><li>Absorptive cells </li></ul><ul><li>Blood capillaries </li></ul><ul><li>Lacteals (specialized lymphatic capillaries) </li></ul>
  18. 23. <ul><li>Large Intestine </li></ul><ul><li>Wider, but shorter,frames the abdomen </li></ul><ul><li>Cecum – saclike first part </li></ul><ul><li>Appendix - Hangs from the cecum </li></ul><ul><li>Colon </li></ul><ul><ul><li>Ascending </li></ul></ul><ul><ul><li>Transverse </li></ul></ul><ul><ul><li>Descending </li></ul></ul><ul><ul><li>S-shaped sigmoidal </li></ul></ul><ul><li>Rectum </li></ul><ul><li>Anus – external body opening </li></ul>
  19. 24. <ul><li>Functions of the Large Intestine </li></ul><ul><li>Absorbs water </li></ul><ul><li>Eliminates feces – indigestible food </li></ul><ul><li>No digestion </li></ul><ul><li>Goblet cells produce mucus as lubricant </li></ul>

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