A Digestive Journey M r .  Masr i SBI   3U Humberside C. I.
What is Homeostasis? <ul><li>Maintaining a balance of your internal environment </li></ul>
<ul><li>Ingestion – the taking of nutrients </li></ul><ul><li>Digestion – the breakdown of complex organic molecules into ...
T ypes of Digestion <ul><li>Mechanical </li></ul><ul><li>Involves chewing, mashing, chopping, breaking food into smaller p...
(a)  Mouth (Oral Cavity)   <ul><li>Food gets lubricated and broken down into smaller pieces (increases surface area) </li>...
<ul><li>For mechanical breakdown  </li></ul><ul><li>incisors (for cutting) </li></ul><ul><li>canines (specialized for tear...
(c) Tongue
(d) Salivary Glands
A.  Tongue  B.  Sublingual glands P.  Submandibular glands N.  Parotid glands O.  Pharynx Q.  Esophagus R.  Cardiac Sphinc...
 
(e)  Esophagus   <ul><li>food tube leading from pharynx to stomach </li></ul><ul><li>at the endpoints of esophagus there a...
Function of Esophagus <ul><li>Moves bolus through to the stomach, through a series of rhythmic contractions called  perist...
 
A.  Tongue  B.  Sublingual glands P.  Submandibular glands N.  Parotid glands O.  Pharynx Q.  Esophagus R.  Cardiac Sphinc...
(f) Stomach
(f) Stomach Esophagus Cardiac Region Fundic Region Pyloric Region
C.  Liver D.  Gall Bladder F.  Common Bile Duct V.  Pancreas
G.  Duodenum M.  Appendix W.  Transverse Colon L.  Cecum Y.  Sigmoid Colon X.  Descending Colon Z.  Rectum I.  Ascending C...
 
Structure of the Wall of the Intestinal Tract  <ul><li>(1) Mucosa </li></ul><ul><li>The inner lining of the gastrointestin...
Villi
Microvilli
 
 
Mucosa … <ul><li>The surface area of each individual intestinal epithelial cell is further increased by  microvilli </li><...
Structure of the Wall of the Intestinal Tract  <ul><li>(2) Submucosa </li></ul><ul><li>The middle layer of the gut wall is...
Structure of the Wall of the Intestinal Tract  <ul><li>(3) Circular and Longitudinal Muscle Layers </li></ul><ul><li>The  ...
Structure of the Wall of the Intestinal Tract  <ul><li>(4) Serosa </li></ul><ul><li>Is the  connective  tissue that  surro...
 
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SBI3U Digestive Tour

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PowerPoint shown in Mr. Masri's Grade 11 Univ. Biology - Humberside C. I.

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SBI3U Digestive Tour

  1. 1. A Digestive Journey M r . Masr i SBI 3U Humberside C. I.
  2. 2. What is Homeostasis? <ul><li>Maintaining a balance of your internal environment </li></ul>
  3. 3. <ul><li>Ingestion – the taking of nutrients </li></ul><ul><li>Digestion – the breakdown of complex organic molecules into smaller components by enzymes </li></ul><ul><li>Absorption – the transport of digested nutrients to the tissues of the body </li></ul><ul><li>Egestion – the removal of waste food materials from the body </li></ul>Steps in Digestion - Alimentary Tract
  4. 4. T ypes of Digestion <ul><li>Mechanical </li></ul><ul><li>Involves chewing, mashing, chopping, breaking food into smaller pieces and the physical movement of food </li></ul><ul><li>Chemical </li></ul><ul><li>Involves enzymes to break food down into macromolecules and nutrients needed at the cellular level </li></ul>
  5. 5. (a) Mouth (Oral Cavity) <ul><li>Food gets lubricated and broken down into smaller pieces (increases surface area) </li></ul><ul><li>Food is now called a BOLUS (a ball of food) </li></ul>
  6. 6. <ul><li>For mechanical breakdown </li></ul><ul><li>incisors (for cutting) </li></ul><ul><li>canines (specialized for tearing) </li></ul><ul><li>premolars (specialized for grinding) </li></ul><ul><li>molars (for crushing) </li></ul>(b) Teeth
  7. 7. (c) Tongue
  8. 8. (d) Salivary Glands
  9. 9. A. Tongue B. Sublingual glands P. Submandibular glands N. Parotid glands O. Pharynx Q. Esophagus R. Cardiac Sphincter
  10. 11. (e) Esophagus <ul><li>food tube leading from pharynx to stomach </li></ul><ul><li>at the endpoints of esophagus there are sphincters (esophageal and cardiac sphincter, respectively) </li></ul><ul><li>Note: the purpose of sphincters is to prevent food from going in the reverse direction (i.e. reflux from the stomach into the esophagus) </li></ul>
  11. 12. Function of Esophagus <ul><li>Moves bolus through to the stomach, through a series of rhythmic contractions called peristalsis </li></ul><ul><li>The circular and longitudinal muscles contract and release </li></ul>
  12. 14. A. Tongue B. Sublingual glands P. Submandibular glands N. Parotid glands O. Pharynx Q. Esophagus R. Cardiac Sphincter T. Stomach U. Pyloric Sphinctor
  13. 15. (f) Stomach
  14. 16. (f) Stomach Esophagus Cardiac Region Fundic Region Pyloric Region
  15. 17. C. Liver D. Gall Bladder F. Common Bile Duct V. Pancreas
  16. 18. G. Duodenum M. Appendix W. Transverse Colon L. Cecum Y. Sigmoid Colon X. Descending Colon Z. Rectum I. Ascending Colon H. Jejunum J. Ileum
  17. 20. Structure of the Wall of the Intestinal Tract <ul><li>(1) Mucosa </li></ul><ul><li>The inner lining of the gastrointestinal tract creates the folds that project into the lumen , which increases the surface area for absorption by three times </li></ul><ul><li>Villi covered with epithelial cells increase the surface area by another factor of 10 </li></ul>
  18. 21. Villi
  19. 22. Microvilli
  20. 25. Mucosa … <ul><li>The surface area of each individual intestinal epithelial cell is further increased by microvilli </li></ul><ul><li>Microvilli create a fuzzy brush border </li></ul><ul><li>These are cells that transport materials, that release hormones, that release enzymes and mucus </li></ul>
  21. 26. Structure of the Wall of the Intestinal Tract <ul><li>(2) Submucosa </li></ul><ul><li>The middle layer of the gut wall is composed of connective tissue with larger blood vessels and lymph vessels </li></ul><ul><li>This layer also contains nerves that help to co-ordinate digestive function </li></ul>
  22. 27. Structure of the Wall of the Intestinal Tract <ul><li>(3) Circular and Longitudinal Muscle Layers </li></ul><ul><li>The inner layer is circular and outer is longitudinal </li></ul><ul><li>Contraction of the circular layer decreases the diameter of the lumen </li></ul><ul><li>Contraction of the longitudinal layer shortens the tube </li></ul>
  23. 28. Structure of the Wall of the Intestinal Tract <ul><li>(4) Serosa </li></ul><ul><li>Is the connective tissue that surrounds the entire digestive tract </li></ul>

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