ALS 2304 Animal Anatomy Final Exam : Digestive System

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  1. 5 Digestive processes
    • 1. Ingestion
    • 2. Propulsion
    • 3. Digestion
    • 4. Absorption
    • 5. Defecation
  2. Ingestion
    taking in food
  3. Propulsion
    • a. Paristalsis- forward movement
    • b. Segmentation- kneading
  4. Digestion
    • a. mechanical
    • b. chemical
  5. Absorption
    a. reabsorption- we produce alot of fluids that need to be reabsorbed
  6. Digestive system peritoneum
    • 1. visceral peritoneum
    • 2. parietal peritoneum
    •      a. Peritoneal cavity
    •      b. peritonitis- inflamation of membrane
    • 3. retroperitoneal- outside of membrane. ex: pancreas
  7. Digestive system blood supply
    • 1. Splanchinic circulation-name of circulatory system to GIT
    •      a. Hepatic portal circulation: capillary to capillary connection between GIT and liver
  8. 4 layers of GIT
    • (medial to lateral)
    • Mucosa
    •    -epithelium
    •    -lamina propria
    •    -musculara mucosa
    • submucosa
    • muscularis externa
    • serosa
  9. Mucosa
    • closest to lumen; secretes mucous, absorbs nutrients
    • 3 sub layers:
    • epithelium: simple columnar; goblet cells make mucous
    • Lamina Propria: loose areolar connective tissue; isolated lymph nodules
    • Musculara mucosa: smooth muscle; movement of mucosa.
  10. submucosa
    Dense connective tissue to support mucosa
  11. Muscularis Externa
    • circular muscle layer: sphincters
    • Longitudinal muscle
  12. Serosa (Visceral peritoneum)
    • adheres to the GIT
    • Serosal fluid inbetween visceral and parietal layers of membrane
  13. Enteric Nervous System
    • Unique nervous system for GIT. Can operate even when de-inervated from outside.
    • 2 nerve plexuses:
    •      a. Submucosal nerve plexus
    •       b. Myenteric plexus
  14. Submucosal nerve plexus
    controls activity of glands and smooth muscle
  15. Myenteric plexus
    between circular and longitudinal muscle
  16. Major parts and functions of Mouth
    • 1. Lined with stratified squamous epithelium
    • 2. Palate
    •      a. Hard: has bone underneath; provides hard surface for mechanical digestion
    •      b. Soft: formed of skeletal muscle: uvula; palate covers nasopharynx when swallowing
    • 3. Tongue: tastebuds, forms bolus, gathers food
    • 4. Salivary gland: cleases mouth, dissolves chemicals, breaks down food, fights bacteria
  17. Extrinsic salivary glands
    • Parotid: location of  mumps
    • Submandibular
    • Sublingual
  18. 4 regions of stomach
    • Cardiac
    • Fundus
    • Corpus (body)
    • Pyloric
  19. 3 divisions of Pyloric region
    • Pyloric antrum
    • Pyloric canal
    • Pyloric sphincter
  20. greater vs. lesser curvature
    inside curve is the lesser curvature. outside (larger side) is the greater curvature
  21. 3 smooth muscle layers of the stomach
    circular, longitudinal, transverse (oblique)
  22. goblet cells
    in epithelium; produce mucous
  23. gastric glands
    • a. mucous neck cells- produce mucous
    • b. Parietal (oxyntic) cells- produce HCl and intrinsic factor to absorb vit. B12
    • c. Chief (peptic) cells- pepsinogen, precursor to pepsin.
  24. Enteroendocrine cells
    • cells along GIT that produce hormones
    • Gastrin, histamine, endorphins, serotoin, cholecystokinin, somatostatin
  25. 4 parts of ruminant stomach
    • 1. Reticulum
    • 2. Rumen
    • 3. Omasum
    • 4. Abomasum
  26. Reticulum
    cranial most portion, honey comb texture made up of stratified squamous epithelium
  27. Rumen
    • largest portion of ruminant stomach.
    • sire of fermentation
  28. Omasum
    water absorption
  29. Abomasum
    True stomach- secretes acid
  30. what are the two structures unique to the avian GIT?
    • Crop: located between mouth and proventriculus. storage space for feed
    • Gizzard: mechanical digestion. 2 main sets of opposing muscle
  31. 3 sections of small intestine
    • Duodenum
    • Jejunum
    • Ileum
  32. Duodenum
    • site of bile addition from liver (hepatopancreatic ampulla)
    • Sphincter of Oddi- site for pancreatic secretions
  33. Ileocecal junction
    where ileum meets colon
  34. Plicae circulares
    funtion: increase surface area
  35. Villi
    • Microvilli (brush border)- simple columnar absorptive cells
    • Brush border enzymes
  36. Central Lacteal
    absorbing fatty acids into lymphatic system
  37. Crypts of Lieberkuhn
    Paneth cells- location of stem cells; lysozyme
  38. Globet cells
    secrete mucus
  39. Submucosa
    location of Peyer's patches (more patches moving posteriorly) and Brunner's glands
  40. What major chemical does the liver produce and how does it function in digestion?
    • the liver produces bile which is then stored in the gall bladder.
    • Bile is an emulsifier- it breaks fat into smaller droplets
  41. T or F: the liver is the largest gland in the body
  42. What is the functional unit of the liver?
    Liver Lobule
  43. Liver lobule
    • a. portal triad: hepatic artery (carries oxygen and nutrients), portal vein (carries material from GIT to Liver) and bile duct (carries bile away from liver)
    • b. Liver sinusoid: leaking capillaries and Kupffer cells (fixed macrophages)
    • c. Hepatic plates made of hepatocytes process nutrients, detoxify ammonia to urea: location of Bile caniculli
  44. Hepatitis
    inflammation of liver
  45. Cirrhosis
    breakdown of liver lobules
  46. Cystic duct
    Gallbladder empties into GIT via cystic duct.
  47. Pancreas
    • major function: produces enzymes (endocrine and exocrine function)
    • Acini cells secrete zymogens- precurser of enzymes
  48. 3 major components of Large Intestine
    • Haustra
    • Cecum
    • Colon
  49. Haustra
    pocket like sacs- no Villi or Plicae circulares
  50. Cecum
    • not present in all species
    • Ileocecal valve: where cecum comes off colon
    • Appendix: Part of MALT
  51. Colon
    Ascending, transverse, descending and Sigmoid colon. (arranged under diaphragm  Right to Left)
  52. Prehension
    acquisition of feed
  53. mastication
  54. deglutition
    • swallowing
    •      a. Primary and secondary persitalsis
    •        i. Primary: tongue moves bolus towards esophagus
    •        ii. Secondary peristalsis: shoving pill down throat.
    •      b. Reverse peristalsis: regurgitation
    •      c. Vomiting: controlled by caudoesophageal sphincter (really tight in horse)
  55. Stomach- receptive relaxtion
    expansion of the stomach, may involve Nitric Oxide
  56. Enterogastric reflex
    • receptors in duodenum; osmotic pressure
    • inhibit emptying- contents of stomach are very acidic and very osmotic. Reflexes try to slow emptying of stomach.
  57. Enterogasterone reflex
    • senses 12-18 carbon lipids and tryptophan (amino acid)
    • causes release of CCK
    • Secretin, VIP and GIP also probably involved.
  58. small intestine
    Transit slowed in ileum due to greater % of segmental contractions (mixing contractions) not forward motion.
  59. Electrical activity: 2 types
    • Slow waves- sympathetic tone
    • spikes- contraction of circular and smooth muscle
    • Pacemaker cells in longitudinal smooth muscle layer; called interstitial cells of cajal
  60. 3 types of gastric secretions
    • 1. Salivary
    • 2. Gastric
    • 3. Pancreatic
  61. Gastric secretions
    • Oxyntic (parietal cells) cells secrete HCl.
    •      a.  one million fold increase in H+ ion concentration Intracellular pH = 6.5
    • Peptic (cheif) cells
    •      a. Secrete pepsinogen
    •      b. Converted to pepsin by HCl
  62. 3 phases to gastric secretion
    • 1.Cephalic:neural via the vagus (sight smell sound)
    • 2.Gastric: gastrin release
    • 3. Intestinal: secretin can cause pepsinogen secretion; acidification of intestin causes Gastrin Inhibition Peptide and slows production of HCl
  63. Pancreatic
    • 1. Enzymes: trypsin, chymotrypsinogen, procarboxypeptidase ( break down proteins) , Amylase (breaks down sugar), lipase (fat), nucleases (DNA, RNA)
    • CCK stimulates enzyme release
  64. Buffer
    • Bicarbonate- balances H+ loss in stomach
    •  release is stimulated by secretin
  65. what controls Bile release?
    controlled by CCK
  66. Digestion and absorption- Carbohydrates
    • starch digestions beings in mouth with amylase
    • Absorb monosaccarides (glucose, fructose, and galactose)
    • 90% absorbed in first 2/3 of small intestine.
    • Pancreatic amylase breaks down starch
    • mucosal digestion: dextrinase and glucoamylase
  67. Described the method of glucose, galactose, fructose.
    • Glucose and galactose: coupled with Na+ absorption. Driven by concentration gradient
    • Fructose: moves down its own concentration gradient
  68. how does protein digestion begin
    • Digestion begins in stomach with pepsin producing polypeptides: pepsin cleaves at bonds having tyrosine and phenylalanine
    • inactivated in duodenum
  69. Protein digestion
    • begins in stomach
    • pancreatic enzymes produce small polypeptides and small peptides
    • brush border enzymes produce amino acids, di- and tri- peptides
    • absorbed like sugars (coupled with Na+)
  70. Lipid digestion
    • small intestine is the only site of lipid digestion
    • bile salts emulsify the fats
    • lipase acts on triglycerides to produce manonglycerides and fatty acids
    • absorbed into enterocytes
  71. Digestion of Nucleic Acids
    DNA and RNA absorbed in small intestine
  72. Vitamins
    • Fat soluble vit. absorbed in small intestine along with fats.
    • water soluble vit absorbed in small intestine
    •      a. B12 requires intrinsic factor from stomach; absorbed in ileum
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ALS 2304 Animal Anatomy Final Exam : Digestive System
flashcards for the powerpoint on digestion.
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