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Other organs of the Digestive System

Mechanical and Chemical Digestion

Absorption

Organs Associated with the

Alimentary Canal • Food does not come into direct contact with

these organs.

Digestive Helpers

• These organs are:

»Liver

»Gallbladder

»Pancreas

Liver

• Produces bile .

• Bile breaks up large fat particles into smaller ones that can be digested easily by enzymes in the small intestine.

• Called emulsification

Do Oil and Water Mix?

1. 2 test tubes. Put 5mL of oil and 5mL of water into each tube.

2. Cover both tubes and shake gently. 3. Add a few drops of soap to the oil-water mixture

of one tube. Repeat step 2.

How can you make oil and water mix? How does the action of liquid soap resemble the

action of bile?

Gallbladder

• Stores bile until needed by the small intestine.

• When food moves into the small intestine from the stomach, the gallbladder releases bile into the small intestine.

• Gallstones: related to poor diet and high fat intake.

Pancreas

• Produces pancreatic juice (mixture of enzymes)

• Pancreatic juice moves into the small intestine the same time bile does to help break down proteins, carbohydrates, and fats

Appendix

• Vestigial organ – functionless due to evolution

• May help the body resist disease-causing bacteria and viruses.

• Appendicitis – when the appendix becomes irritated, inflamed, or infected.

• The only cure is to have

the appendix surgically

removed as soon as possible.

Summary of Organs that Make Up the Digestive System

Alimentary Canal

• Mouth (teeth, tongue)

• Pharynx

• Uvula

• Epiglottis

• Esophagus

• Stomach

• Small intestine

• Large intestine

• Rectum

• Anus

Accessory Organs

• Liver

• Gallbladder

• Pancreas

*Appendix is not directly associated with the digestive system.

Reviewing Components of the Digestive System

• Review of the Digestive System

If you had a broken jaw and were unable to chew your food, how could you help your

digestive system out?

2 Types of Digestion

• Mechanical Digestion

– Physical break down of large food particles into smaller ones

– Prepares food for faster chemical digestion

• Chemical digestion

– Chemical break down of small food particles into nutrients that can be used by cells of the body.

• Completed by enzymes

Mechanical Digestion

• Reduces the size of large food pieces to smaller ones thereby increasing the surface area.

• Allows for more surface contact between the food and the enzymes that assist in breaking them down.

Mouth – mastication

Esophagus – peristalsis

Stomach – churning

Small Intestine – emulsification of fats by bile

Chemical Digestion

• Larger molecules are broken down into their simplest form – used by the body.

• Carried out by digestive enzymes.

– Mouth – Amylase begins the digestion of starches

– Stomach – Pepsin begins the digestion of proteins

– Small Intestine – Pancreatic juice breaks down fats (lipids), proteins, and carbohydrates (starches)

• Kitses Review

Absorption

• Absorption is important in transporting nutrients from the digestive system into the blood stream.

• Water re-absorption in the large intestine.

• Nutrient absorption in the small intestine.

– Inner surface has long finger-like projections called villi (increases the surface area for absorption)

Villi

Microvilli