1. 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

2. 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

3. Accessory Digestive Organs
Teeth
Salivary glands
Pancreas
Liver
Gallbladder

4. 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

5. Salivary Glands
Three pairs of salivary glands empty secretions into the mouth
parotid
sublingual
submandibular

6. 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)

7. Pancreas Found posterior to the parietal peritoneum
Extends across the abdomen from spleen to duodenum
Connected to the duodenum via various ducts

8. 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

9. Liver (Hepa- 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

10. Liver Produces bile: a yellow-green substance
Physically breaks down fat to increase surface area: process known as emulsification
Stored in the gall bladder

11. 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