Accessory Digestive Organs Teeth Salivary glands Pancreas Liver

Accessory Digestive Organs § Teeth § Salivary glands § Pancreas § Liver § Gallbladder Copyright © 2009 Pearson Education, Inc. , publishing as Benjamin Cummings

Functions of the Digestive System § Food breakdown as mechanical digestion § Breaking large pieces into small pieces (increase surface area) § Prepares food for further degradation by enzymes § Examples: § Mixing food in the mouth by the tongue § Churning food in the stomach § Segmentation in the small intestine Copyright © 2009 Pearson Education, Inc. , publishing as Benjamin Cummings

Functions of the Digestive System § Food breakdown as chemical digestion § Enzymes break down food molecules into their building blocks § Each major food group uses different enzymes § Carbohydrates (polysaccharides/starches) are broken to simple sugars monosaccharides/glucose) § Proteins (peptides) are broken to amino acids § Lipids (Fats) are broken to fatty acids and glycerol *Cellulose is a carbohydrate that cannot be broken down by our digestive system and is referred to as ruffage or fiber- it helps clean the system Copyright © 2009 Pearson Education, Inc. , publishing as Benjamin Cummings

Teeth § Function is to masticate (chew) food § Humans have two sets of teeth § Deciduous (baby or “milk”) teeth § 20 teeth are fully formed by age two § Permanent teeth § Replace deciduous teeth between the ages of 6 and 12 § A full set is 32 teeth, but some people do not have wisdom teeth (third molars) § If they do emerge, the wisdom teeth appear between ages of 17 and 25 Copyright © 2009 Pearson Education, Inc. , publishing as Benjamin Cummings

Salivary Glands § Three pairs of salivary glands empty secretions into the mouth parotid sublingual submandibular Copyright © 2009 Pearson Education, Inc. , publishing as Benjamin Cummings

Saliva § Contains mucus, helps to form a food bolus § Contains salivary amylase to begin starch digestion § Has antimicrobial properties and contains phagocytes § Dissolves chemicals so they can be tasted § Is continuously made throughout the day, peeking in the afternoon § Can also be stimulated to produce more saliva at other times (mouth waters) Copyright © 2009 Pearson Education, Inc. , publishing as Benjamin Cummings

Pancreas § Found posterior to the parietal peritoneum § Extends across the abdomen from spleen to duodenum § Connected to the duodenum via various ducts Copyright © 2009 Pearson Education, Inc. , publishing as Benjamin Cummings

Pancreas § Produces buffer (alkaline substance) § Neutralizes stomach acids still in the chyme § Produces enzymes § Pancreatic amylase: continues the breakdown of starch into glucose § Protease: breaks proteins into amino acids § Lipase: breaks fat into fatty acids and glycerol Copyright © 2009 Pearson Education, Inc. , publishing as Benjamin Cummings

Liver § Largest gland in the body § Located on the right side of the body under the diaphragm § Consists of four lobes § Connected to the duodenum via the common hepatic duct Copyright © 2009 Pearson Education, Inc. , publishing as Benjamin Cummings

Liver § Produces bile: a yellow-green substance § Physically breaks down fat to increase surface area: process known as emulsification § Stored in the gall bladder Copyright © 2009 Pearson Education, Inc. , publishing as Benjamin Cummings

Gall bladder § Sac-like structure § Found embedded in the lower liver § Stores bile backed up in the duct § Hormonally controlled to release bile to duodenum Copyright © 2009 Pearson Education, Inc. , publishing as Benjamin Cummings