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Digestion In The Mouth And Swallowing Notes

Medicine Notes > Gastrointestinal (GI) System Notes

This is an extract of our Digestion In The Mouth And Swallowing document, which we sell as part of our Gastrointestinal (GI) System Notes collection written by the top tier of Bristol University students.

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Lecture 4 Digestion in the Mouth and Swallowing



Salivary secretion and digestion in mouth o Digestion in the mouth
? No digestion of proteins in the mouth
? Digestion

* Starch-----Amylase: pH7-----> Oligosaccharides
? Motility

* Chewing= Chop food into small pieces, mix with saliva

* Swallowing= Move food to lower parts of GI tract o Glands
? Parotid gland

* Serous (i.e. watery) secretion rich in a-amylase
? Submandibular and sublingual glands

* Seromucous secretion
? Minor salivary glands

* Scattered throughout oral cavity

* Mucous secretion rich in mucin glycoproteins o Salivary secretion
? 1.5 litres per day; Hyperosmotic (osmolarity less than that of blood); pH
? Composition includes

* Mucin glycoproteins

* Lysozyme (anti-microbial, protecting from infection)

* a-amylase

* Proline-rich proteins (protect enamel/epithelial cells by neutralising tannings, lubrication)
? Functions

* Lubricate food, make swallowing easier (mucin glycoproteins, H2O)

* Clean & protect cavity of mouth (lysozyme, proline-rich proteins)

* Reduce starch to oligosaccharide molecules (a-amylase) o General structure of salivary glands
? Main collecting duct
? Interlobular duct (lobule= secretory unit)
? Intercalated ducts
? Acinar cell (zymogen granules)
? Duct epithelial cells Saliva o Composition determined by both Acinar and Duct-lining Epithelial cells
? Acinar cells

* Generate primary secretion

* Needed to wash out secretions into mouth (NaCl & H2O)

* Cl- & a-amylase moves through cells, Na & H20 moves between cells

* Leaky epithelia
? Duct-lining epithelial cells

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