Unit 2: Digestion - Weebly
Transcript of Unit 2: Digestion - Weebly
Digestion Notes.notebook
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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
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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
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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
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• 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