1. The process of breaking down food groups into molecules that are small enough to be utilized by the cells of the body
  2. Overview of GI tract Functions:
    Mouth---bite, chew, swallow
  3. Overview of GI tract Functions:
    Pharynx and esophagus
  4. Overview of GI tract Functions:
    • -mechanical & chemical disruption
    • -absorption of water & alcohol
  5. Overview of GI tract Functions:
    absorbs electrolytes & vitamins (B and K)
    Large intestine
  6. Overview of GI tract Function
    Rectum & Anus
  7. Where is the peritoneum serous membrane found?
    abdominal cavity
  8. Covers organs
    Visceral layer of peritoneum
  9. Lines the walls of body cavity
    Parietal layer of Peritoneum
  10. Potential space containing a bit of serous fluid
    Peritoneal cavity
  11. What are the 4 layers of the GI Tract?
    • 1. Mucosal layer- epithelium, lamina propria and muscularis mucosa
    • 2. Submucosal layer- connective tissue and submucosal plexus
    • 3. Muscularis layer- smooth muscle and myenteric plexus
    • 4. Serosa layer –visceral peritoneu
  12. Contains buccinator muscle that keeps food between upper & lower teeth
    Lips & Cheeks
  13. Area between cheeks and teeth
  14. -the roof = hard, soft palate and uvula
    -the floor= the tongue
    Oral cavity proper
  15. Pharyngeal Arches consists of __ muscles
  16. – extends from palate to tongue
    – forms the first arch
    – posterior limit of the mouth
    Palatoglossal arch
  17. – extends from palate to pharyngeal wall
    – forms the second arch
    – between: palatine tonsil
    Palatopharyngeal arch
  18. • Parotid below your ear and over the masseter
    • Submandibular is under lower edge of mandible
    • Sublingual is deep to the tongue in floor of mouth
    • All have ducts that empty into the oral cavity
    Salivary Glands
  19. •Wet food for easier swallowing
    • Dissolves food for activation of taste receptors
    • Bicarbonate ions buffer acidic foods
  20. Chemical digestion of starch begins with _______ (salivary amylase) and _____ (lingual lipase)
    enzyme; fats
  21. Composition & Functions of Saliva:
    Helps destroy bacteria
    Enzyme (lysozyme)
  22. Protects mouth from infection with its rinsing action---1 to 1.5 l/day
  23. What are the 5 structures of a tooth?
    • • Crown
    • • Neck
    • • Roots
    • • Pulp cavity (contains connective tissue, blood vessels, nerves and lymphatic vessels)
    • • Root canal
  24. Composition of Teeth:
    – hardest substance in body
    – rich in calcium salts (calcium phosphate and carbonate)
  25. Composition of Teeth:
    – calcified connective tissue (harder than bone-more calcium salts)
  26. Composition of Teeth:
    – bone-like
    – periodontal ligament (fibrous connective tissue) connects cementum to bone socket
  27. Dentition:
    – 20 teeth that start erupting at 6 months
    – 1 new pair of teeth per month
    Primary or baby teeth
  28. Dentition:
    – 32 teeth that erupt between 6 and 12 years of age
    – differing structures indicate function
    Permanent teeth
  29. What teeth for:
    for biting
  30. What teeth for:
    Canines or cuspids
  31. What teeth for:
    Crushing & grinding food
    Premolars & molars
  32. What teeth:
    Third set of molars may impact (no room)
    Wisdom teeth
  33. -Funnel-shaped tube extending from internal nares to the esophagus (posteriorly) and larynx (anteriorly)
    -Skeletal muscle lined by mucous membran
  34. Deglutition or swallowing is facilitated by _____ and ______
    saliva; mucus
  35. Physiology of the Esophagus - Swallowing
    --tongue pushes food to back of oral cavity
    Voluntary phase
  36. Physiology of the Esophagus - Swallowing
    ---pharyngeal stage
    Voluntary phase
  37. – breathing stops & airways are closed
    – soft palate & uvula are lifted to close off nasopharynx
    – vocal cords close
    – epiglottis is bent over airway as larynx is lifte
    Involuntary phase----pharyngeal stage
  38. • Collapsed muscular tube
    • In front of vertebrae
    • Posterior to trachea
    • Posterior to the heart
    • Pierces the diaphragm at hiatus
  39. Histology of the Esophagus
    Mucosa is composed of which type of tissue?
    stratified squamous cells
  40. Histology of the Esophagus
    large mucous glands
  41. Histology of the Esophagus
    Upper 1/3 is skeletal, middle is mixed, lower 1/3 is smooth
  42. Upper esophageal sphincter prominent circular muscle, lower sphincter is narrowing of lumen, physiological
  43. Histology of the Esophagus:
    connective tissue blending with surrounding connective tissue--no peritoneum
  44. Size of the stomach when empty
    Large sausage
  45. Stomach stretches due to _______
  46. What are the 3 parts of the stomach?
    • Cardis
    • Fundus
    • Body
    • Pylorus
  47. Which part of the stomach starts to narrow as approaches pyloric sphincter
  48. Empties as small squirts of ________leave the stomach through the pyloric valv
  49. Secrete pepsinogen and gastric lipase (fat digestion)
    Chief (zymogenic) cells
  50. Secrete HCL –converts pepsinogen to pepsin (protein digestion) and intrinsic factor- absorption of vitamin B12 for RBC production
    Parietal cells
  51. Secrete Gastrin hormone (g cell)- release more gastric juice, increase gastric motility, relax pyloric sphincter, constrict esophageal sphincter preventing entry
    G cells
  52. Three layers of smooth muscle--outer longitudinal, middle circular & inner oblique
  53. Permits greater churning & mixing of food with gastric juice
  54. Chemical Digestion:
    – HCl denatures (unfolds) protein molecules
    – HCl transforms pepsinogen into pepsin that breaks peptides bonds between certain amino acid
    Protein digestion begins
  55. Chemical Digestion:
    – gastric lipase splits the triglycerides in milk fat
    Fat digestion continues
  56. Chemical Digestion:
    Kills microbes in food
  57. Protect stomach walls from being digested with 1-3mm thick layer of mucous (aspirin inhibits mucous formation)
    Mucous cells
  58. What is absorbed by the stomach?
    • • Some water
    • • Electrolytes
    • • Some drugs (especially aspirin) & alcohol
  59. 3 meters long----2.5cm in diameter
    Large surface area for majority of absorption
    Small Intestine
  60. What are the 3 parts of the small intestine?
    • – duodenum
    • – jejunum
    • – ileum (ends at ileocecal valve)
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