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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