Digestion Notes.notebook

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February 27, 2014

Digestion is...

Unit 2: Digestion

Digestion: The chemical and mechanical break down of food and drink into smaller, units for absorption.

Digestive anatomy

Feb 27­9:01 PM

Mechanical Digestion: The physical break down of food into smaller units

• peristalsis

• mastication

Nov 12­9:47 PM

Chemical Digestion: The break down of food by enzymes in the body

SUBSTRATE

PRODUCT

Oct 1­7:47 AM

SUBSTRATE

PRODUCT

Oct 1­7:48 AM

SUBSTRATEPRODUCT

Digestion Notes.notebook

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February 27, 2014

Oct 1­7:46 AM

SOURCE ENZYME SUBSTRATE PRODUCT

MOUTH (salivary glands) Amylase Starches Maltose

STOMACHPepsin Proteins Peptides

PANCREAS (releases juices into small intestine)

P. Amylase Starches Maltose

Trypsin Proteins Peptides

Lipase Fats Fatty acids and glycerol

SMALL INTESTINE

Maltase Maltose Glucose

Peptidases Peptides Amino acids

Lactase lactose Glucose etc

Chemical Digestion Table

Oct 17­1:59 PM

Ex. Describe digestion of pasta(starch) from ingestion to egestion

The process of digestion begins in the mouth with mastication (chewing). The amylase from the salivary glands binds to the substrate (pasta/starch) and breaks it down into maltose.

The food passes through the pharynx and down the esophagus where peristalsis (muscular contractions) occurs.

The bolus of pasta enters the stomach where peristalsis continues.

The bolus enters the small intestine where P. amylase breaks residual starch into maltose. Maltase then breaks the maltose down into glucose.

The food continues through the large intestine where water is absorbed and the waste is compacted. Then it is excreted out the anus.

Parts of Digestive System

Parts of the Digestive Systemin the order in which a particle of food will travel

The Mouth

AMYLASE

Glucose Maltose Starch

The Mouth• Salivary glands release amylase• amylase breaks starch down into maltose • mastication

Feb 27­9:12 AM

Mouth/Pharynx/Epiglottis/Tongue/Uvula

• teeth for mastication• epiglottis to keep food out of trachea

• tongue forms bolus• uvula for swallowing

Oct 1­8:07 AM

The EpiglottisPrevents food/liquid from entering the trachea--> lungs

Digestion Notes.notebook

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February 27, 2014

Feb 27­11:14 PM

The Esophagus• peristalsis• delivers food from mouth to stomach

The Stomach

The Stomach

• peristalsis• Acid (HCl) aids with chemical digestion• creates chyme• Rugae allow stomach to expand• Mucous lining

Small Intestine and Pancreas

Small Intestine

Split in 3; • duodenum, • jejunum and • ileum

Feb 27­9:50 PM

• Duodenum: where the pancreatic and bile ducts open and much chemical digestion occurs

Feb 24­10:45 AM Feb 27­9:50 PM

• Jejunum and Ileum have villi, which increase the surface area of the small intestine

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Nov 6­9:36 PM

Large Intestine

• also known as the large bowel or colon

• absorbs water

• compacts fibre and other undigestible material

• stores waste before elimination

Feb 27­9:27 AM

The Appendix• vestigial organ?• immune system response?• houses important bacteria?• removed frequently because of

inflammation

Feb 27­11:35 PM

The Three Accessory Digestive Organs

1. The Liver

• creates bile to break down fats

• second largest organ in body

• Detoxifies materials absorbed from the small intestine

Feb 27­11:48 PM

2. The Gallbladder

• stores bile from the liver

• releases bile into duodenum of small intestine

Feb 27­11:48 PM

3. The Pancreas

• produces digestive juices and insulin

• secretes Sodium Bicarbonate to neutralize the acidic chyme