Download Digestive System Short

Digestive System
A brief tour
1
Functions



Ingestion
Propulsion
Digestion
– Mechanical
– Chemical


Absorption
Defecation
2
Anatomy


Alimentary canal
Accessory organs
3
Alimentary Canal



Structure
Propulsion: Peristalsis
Four tunics
4
Alimentary Canal

Oral cavity
– Mechanical digestion:
teeth, tongue, saliva
– Chemical digestion:
salivary amylases


Pharynx
Esophagus
– Esophageal sphincter
5
Alimentary Canal

Stomach
– Mechanical digestion
– Chemical digestion: proteases
– Gastric juice: HCl,
HCl, pepsinogens,
pepsinogens, mucous
6
Alimentary Canal

Small intestine
– Digestion & absorption!
– Pyloric sphincter
– Divisions
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Alimentary Canal

Small intestine
– Absorption
 Circular
folds
 Villi & microvilli
 Lacteals
 Peyer’
Peyer’s patches
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Alimentary Canal

Small intestine
– Chemical digestion
 Brush
border enzymes
 Pancreatic enzymes
 Bile
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Alimentary Canal

Large intestine
– Water & vitamin absorption, defecation
– Divisions
 Colon:
ascending,
transverse, descending,
sigmoid
 Rectum
 Anal canal
– Appendix
10
Accessory Organs


Teeth & tongue
Salivary glands
– Salivary amylases
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Accessory Organs

Pancreas: Pancreatic enzymes
– Pancreatic amylases
– Proteases (trypsin
(trypsin))
– Lipases
– Nucleases
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Accessory Organs

Liver & gall bladder
– Bile:
Bile: fat emulsification
– Liver: produces bile
– Gall bladder: stores
bile
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Chemical digestion recap

Carbohydrates (sugars, starches)
– Digested by: amylases into
monosaccharides
– Digestion:
 Mouth
(starches): salivary amylases
 Small intestine:
– Pancreatic amylases (starches)
– Brush border enzymes (sugars)
– Absorption: Small intestine  liver
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Chemical digestion recap

Proteins
– Digested by: Proteases into amino acids
– Digestion:
 Stomach
(pepsin: large proteins)
 Small intestine (brush border enzymes,
pancreatic proteases: small proteins)
– Absorption: Small intestine  liver
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Chemical digestion recap

Lipids
– Digested by: Lipases into fatty acids,
glycerols,
glycerols, glycerine
– Digestion: small intestine
 Emulsified
by bile salts from liver/gall bladder
 Digested by pancreatic lipases
– Absorption:
intestine  Lacteals  T.D.
 Small intestine  liver
 Small
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Chemical digestion recap

Nucleic acids
– Digested by: Nucleases into nucleotides
– Digestion: small intestine
 Digested
by pancreatic nucleases
– Absorption: Small intestine  liver
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