1729677036450.pdf digestive system Module pdf

Digestive system pdf for seminar and study materials for exams

1. DIGESTIVE SYTEM
Soumya K P
Assistant Professor in Physiology

2. Digestive System Organization
•Gastrointestinal (Gl) tract
–30 feet, Tubular structure-from mouth to anus
–Direct link/path between organs
–Structures
•Mouth
•Pharynx
•Esophagus
•Stomach
•Small intestine
•Large Intestine
•Rectum
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3. Accessory Organs The Glands
•Not part of the path of food, but play a critical
role.
•Accessory digestive organs
Teeth, Tongue, Salivary glands, Exocrine
parts of pancreas,
Liver, Gallbladder.
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4. Digestion
•Phases Include
1.Ingestion
2.Movement
3.Mechanical and Chemical Digestion
4.Absorption
5.Elimination

5. Digestion
•Types
–Mechanical (physical)
•Chew
•Tear
•Grind
•Mash
•Mix
–Chemical
•Enzymatic reactions to improve digestion of
–Carbohydrates
–Proteins
–Lipids

6. Mouth
•Ingestion of food materials
•Chewing the food and mixing it with saliva
•Appreciation of the taste of food
•Transfer of food (bolus) to the stomach
•Role in speech
•Social functions
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7. Mouth
•Teeth mechanically
break down food into
small pieces. Tongue
mixes food with saliva
(contains amylase,
which helps break down
starch).
•Epiglottis is a flap-like
structure at the back of
the throat that closes
over the trachea
preventing food from
entering it.It is located
in the Pharynx.

8. Salivary Glands
•Major salivary glands
1. Parotid glands
2.submaxillary/
mandibular glands
3. sublingual glands
•Minor salivary glands
1.Lingual mucous glands
2.Lingual serous glands
3.Buccal glands
4.Labial glands
5.Palatal glands
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10. Saliva -functions
•Preparation of food for swallowing-mucin
•Appreciation of taste-chemical stimulation
•Digestive function
•Cleansing and protective function
•Role in speech
•Excretory function
•Regulation of body temperature
•Regulation of water balance
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11. Esophagus
•Approximately 20 cm long.
•Functions include:
1.Secrete mucus
2.Moves food from the throat to
the stomach using muscle
movement called peristalsis
•If acid from the stomach gets in
here that’s heartburn.

12. Stomach
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•J-shaped muscular bag that stores the food you
eat, breaks it down into tiny pieces.
•Mixes food with Digestive Juices that contain
enzymes to break down Proteins and Lipids.
•Acid (HCl)in the stomach Kills Bacteria.
•Food found in the stomach is called Chyme.
•Gastric glands-produce gastric juice

13. Functions of stomach
•Mechanical functions –storage & chyme
formation
•Digestive functions –act mainly on proteins
pepsin & renin
•Protective functions -mucoprotein
•Hemopoietic functions-intrinsic factor castle
•Excretory functions –toxin, alkaloids & metals
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15. Gastric glands –gastric juice
•Digestive function –act mainly on proteins
pepsin & renin
•Hemopoietic function –intrinsic factor castle
•Protective function-mucoprotein
•Functions of Hcl-activates pepsinogen
kills bacteria
provides acidic medium
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16. Phases of gastric secretion & regulation
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17. Pancreas

18. Pancreas
•Produces digestive
enzymes to digest fats,
carbohydrates and
proteins
•Regulates blood sugar
by producing insulin
Web Page Reinforcement Video

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20. Functions of pancreas
•Digestive functions
Digestion of proteins
trypsin, chymotrypsin, nucleases
carboxypeptidase, elastase, collagenase
Digestion of lipids
pancreatic lipase, cholesterol ester
hydrolase, phospholipase A&B,
colipase, bile salt activated lipase
Digestion of Carbohydrates-pancreatic amylase
•Neutralizing action
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21. Phases of pancreatic secretion & regulation
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22. Hormones inhibiting pancreatic
secretion
•Pancreatic polypeptide by PP cells
•Somatostatin by D cells
•Peptide YY by intestinal mucosa
•Peptides like ghrelin and leptin

23. Liver
•Directly affects digestion by producing
bile
–Bile helps digest fat
•filters out toxinsand waste including
drugsand alcohol and poisons.
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24. Functions of liver
•Metabolic functions-Carbohydrates,
protein, fat, vitamins, hormones
•Storage functions-Glycogen, amino acids,
iron, folic acid and vit A,B12, D
•Synthetic functions-Gluconeogenesis
•Secretion bile
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25. •Excretory function-cholesterol, bile
pigments, heavy metals, toxins, bacteria,
virus
•Heat production
•Hemopoietic functions –in fetus
•Hemolytic functions
•Inactivation of hormones & drugs
•Defensive and detoxification function
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26. Composition of bile
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27. Functions of bile
•Digestive function -fat
•Absorptive function -fat
•Excretory function –heavy metals, some
bacteria, toxins, cholesterol,
lecithin,alkaline phosphatase
•Laxative function-bile salt induces
defecation
•Antiseptic function-inhibit growth of
bacteria
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28. •Choleretic action-stimulates bile
secretion
•Maintenance of pH in GIT
•Prevention of gallstone formation
•Lubrication function-mucin
•Cholagogue function-contraction of
gallbladder & release bile
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29. Gall Bladder
•Stores bile from the
liver, releases it into the
small intestine.
•Concentration of bile
•Alteration of pH of bile
•Secretion of mucin

30. Small Intestine
•Small intestines are roughly 7meters long
•Lining of intestine walls has finger-like
projections called villi,to increase surface
area.
•The villi are covered in microvilli which
further increases surface area for
absorption.
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Crash Course Review

31. Small Intestine
•Nutrients from the food pass into the
bloodstreamthrough the small
intestine walls.
•Absorbs:
–80% ingested water
–Vitamins
–Minerals
–Carbohydrates
–Proteins
–Lipids
•Secretes digestive enzymes
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32. Composition of succus entericus
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33. Large Intestine
•About 1.5 meters long
•Accepts what small intestines don’t
absorb
•Rectum(short term storage which
holds feces before it is expelled).

34. Large Intestine
•Functions
–Bacterial digestion
•Ferment carbohydrates
–Absorbs more water
–Concentrate wastes

36. On a sheet of paper, write the name of
each colored organ:
•Green:
•Red:
•Pink:
•Brown:
•Purple:
•Green:
•Yellow:

37. How’d you do?
•Green: Esophagus
•Red: Stomach
•Pink: Small Intestine
•Brown: Large Intestine
•Purple: Liver
•Green: Gall Bladder
•Yellow: Pancreas
Great Job!

38. Thank you
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