Digestive System

Consists of three layers of tissue: • Muscous membrane - protection, secretion and absorption • Lamina propia - loose connective tissue which supports blood vessels and contains lymphoid tissue • Muscularis mucosa - think outer layer of smooth muscle that provides involutions of hte mucosa laywer (ie. gastric glands and villi)

• Stomach - B12 absorbtion • Small intestine - Water solualble vitamins absorbed into capillaries, fat soluable into lacteals of villi. • Large instestine - bacteria synthesize vitamin K, absorbed in the colon

• Contains amylase an enzyme which beings the breakdown of complex sugars including starches (carbs) into disaccharide maltose. • Lubriation of food • Cleaning & lubrication of mouth • Non-specific defence (lysoyme & immunoglobulins) • Taste

1500ml produced per day. Contains: • water • mucous • mineral salts Has a pH of approximately 7.8

• Pharynx above and diaphragm below. • Contains upper (prevents air into esophagus) and lower (prevents gastric acid into the esophagus) sphincters

Occurs before food reaches the stomach. Due to reflex stimulation of vagus nerves (parasympathetic)

Chyme is mixed with: • Pancreatic Juice • Bile • Intestinal Juice Disgestion of all nutrients is completed. • Carbohydrates–> monosaccharides • Proteins–> amino acids • Fats –> Fatty acids and glycerol

Largest gland in the body. Totally enclosed in a layer of peritoneum. Consists of four lobes. • right (small) & left lobes (large) • caudate & quadrate lobes (posterior)

Include: insulin, glucagon, corisol, aldosterone, thyroid and sex hormones.

• Hydrocloric acid in the stomach (pepisnogen–>pepsin) • Enterokinase digestion in the small intestine • Into the blood via capillaries in the villi

• Salivary amylase in the mouth • Hydrochloric Acid in the stomach • Pancreatic amylase in the small intestine • Absorption into blood via villi

Libricates the walls of the tract and provides them from damage from enzymes.

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• 3 pairs of salivary glands • The Pancreas • The Liver and Biliary tract

• Mouth • Pharynx • Esophagus • Stomach • Small Intestine • Large Instestine • Rectum & anal canal

Necessary for the absorption of B12 from the ileum.

Process of breaking down large molecules into smaller ones

When partially digested food reaches the small instestine, endocrine cells in the intestine produce two hormones Secretin Cholecystokinin which slow down the production of gastric juice and reduce gastric motility.

Pancreatic amylase converts all digestible polysaccharides (starches) not acted upon by the salivary amylase to disaccharides.

Process of building up or synthesizing large molecules from smaller ones. Process requires ATP.

Heavily colonized with bacteria which synthesize vitamin K and folic acid. Microbes are normally harmless but can cause problems if tranferred to other parts of the body.

When the body makes glucose from non-carbohydrate sources such as amino acids, and glycerol

Link between the small and large intestine.