Pages 473-476 and 494-497. Teeth – mechanical digestion through mastication Salivary glands – parotid, submandibular, sublingual ◦ Secrete saliva,

Pages 473-476 and 494-497

Teeth – mechanical digestion through mastication

Salivary glands – parotid, submandibular, sublingual◦ Secrete saliva, a bicarbonate rich juice◦ chemical digestion via secretions of enzymes

Salivary amylase begins starch digestion

◦ Saliva also contains lysozyme and antibodies to inhibit bacteria

Pancreas Liver Gallbladder

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Mouth (oral cavity)

Tongue

Esophagus

Parotid glandSublingual glandSubmandibulargland

Salivary glands

Pharynx

StomachPancreas

Transverse colonDescending colon

Ascending colon

CecumSigmoid colonRectumAppendixAnal canalAnus

Smallintestine

DuodenumJejunumIleum

Liver

Gallbladder

Large intestine

Produces digestive enzymes that break down all categories of food◦ releases into the duodenum via the

hepatopancreatic ampulla◦ Alkaline (bicarbonate) fluid with these enzymes

neutralizes the acidic chyme Produces hormones: (negative feedback

loops)◦ Insulin – reduces blood glucose ◦ Glucagon – raises blood glucose

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Right and lefthepatic ductsfrom liver

Cystic ductCommon hepatic duct

Bile duct and sphincter

Accessory pancreatic duct

Pancreas

Jejunum

Main pancreatic duct and sphincter

DuodenumHepatopancreaticampulla and sphincter

Duodenalpapilla

Gallbladder

largest gland in the body; consists of four lobes

can regenerate if part is damaged/removed

suspended from the diaphragm and abdominal wall by the falciform ligament

Connected to the gallbladder via the common hepatic duct

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the body’s key metabolic organ After the GI tract, blood travels to liver via the hepatic

portal circulation

Roles in digestion:◦ Manufactures bile and blood clotting proteins◦ Detoxifies drugs and alcohol◦ Degrades hormones◦ Produces cholesterol:

Low Density Lipoproteins: transport cholesterol/lipids to the cells; large amounts circulating can build up in vessel lumen (BAD GUYS)

High Density Lipoproetins: transport cholesterol from the cells to the liver for disposal in bile (GOOD GUYS)

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The liver manages blood glucose levels through:

◦ Glycogenesis:◦ Glucose is removed from the blood (via insulin)◦ Converted to glycogen and stored in the liver

◦ Glycogenolysis:◦ Glucose is released into the blood (via glucagon)◦ Glycogen is “split” and put back into blood

◦ Gluconeogenesis:◦ The Liver can make glucose using fats and amino acids

Right and lefthepatic ductsfrom liver

Cystic ductCommon hepatic duct

Bile duct and sphincter

Accessory pancreatic duct

Pancreas

Jejunum

Main pancreatic duct and sphincter

DuodenumHepatopancreaticampulla and sphincter

Duodenalpapilla

Gallbladder

produced by cells in the liver a yellow-green, watery solution containing:

◦ Bile salts and bile pigments (mostly bilirubin from the breakdown of hemoglobin)

◦ Cholesterol, phospholipids, and electrolytes leaves the liver via the common hepatic

duct◦ enters duodenum through the bile duct

Function: emulsify fats◦ Chemically breaks large fat globules into smaller

ones

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Sac found in shallow fossa of liver When no digestion is occurring:

◦ bile backs up the cystic duct for storage in the gallbladder Water is removed at this time to concentrate it

Gallstones◦ crystallized cholesterol that can cause blockages

Result from removal of too much water Prolonged storage in gallbladder

© 2015 Pearson Education, Inc.

Right and lefthepatic ductsfrom liver

Cystic ductCommon hepatic duct

Bile duct and sphincter

Accessory pancreatic duct

Pancreas

Jejunum

Main pancreatic duct and sphincter

DuodenumHepatopancreaticampulla and sphincter

Duodenalpapilla

Gallbladder