Digestive System

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Digestive System

• Ms. Lowrie
• Biology 11

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Did You Know?

• Tube from mouth to rectum 32 feet
• Swallow 4 to 6 seconds
• Stomach size can double
• In stomach for 1 to 6 hours
• Small intestine 22 feet
• Width of tennis court
• 3 hours
• Large intestine
• 18 hours to 2 days

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Purpose

• PlantsAutotrophs
• Make own food
• Photosynthesis
• AnimalsHeterotrophs
• Must eat to survive
• Organic compounds
• Used for energy, growth repair

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Five Functions

• Ingestion
• Consuming food
• Occurs in mouth
• Digestion
• Breaking apart food into a smaller form
• Mechanical or chemical
• Occurs in mouth, stomach, small intestine

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Five Functions (cont.)

• Transportation
• Movement of materials through digestive tract
• Occurs by peristalsis
• Wavelike contraction of muscles

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Peristalsis
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Five Functions (cont.)

• Absorption
• Moving nutrients into circulatory system
• Occurs in small and large intestines
• Elimination (Egestion)
• Removing undigested or unabsorbed materials
• Occurs by rectum (storage) and anus

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DigestionMechanical vs. Chemical

• Mechanical
• Physically breaking apart food
• Food is broken into smaller pieces
• Examples
• Teeth, tongue, esophagus, stomach muscles, liver
  (bile)

• Chemical
• Chemical bonds break
• Using acid or enzyme
• Food is broken into building blocks
• Examples
• Mouth (salivary glands), stomach acids, small
  intestines

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Mechanical or Chemical? Eating a Banana

1. Teeth chew it
2. Tongue moves it around the mouth
3. Salvia starts to break it down
4. Tongue pushes it into my esophagus
5. Muscles in esophagus push it down toward stomach
6. Stomach muscles move it around
7. Stomach acids start to break it down
8. Small intestine releases enzymes to break it down

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Are you still hungry?
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Task

• Using pages 208 226
• Label diagram
• Complete Part Chart
• Describe the function(s) of each part

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Diagram
Mouth
Pharynx
Salivary Glands
Esophagus
Stomach
Liver
Pancreas (behind the stomach)
Gallbladder (behind the liver)
Large Intestine
Small Intestine
Anus
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Salivary Glands

• Lubricates food
• For swallowing
• Activates taste buds
• Starts breakdown of carbohydrates

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Mouth Teeth

• Mechanical digestion
• Including tongue
• Food chewed into a bolus
• Ball of food

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Did you know?

• How do toothless animals, like birds, chew?
• Use a gizzard
• Organ filled with small pebbles or sand
• Why?
• Speeds up eating
• Vulnerable to predators when eating

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Esophagus

• Tube
• Carries food from mouth to stomach
• Movement regulated by peristalsis

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Task Text Questions

• Practice Questions
• 1, 2 (pg 212)
• Section Questions
• 4, 5 (pg 214)

• Using
• Notes
• Textbook
• Section 6.3

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Stomach

• Food storage
• Chemical digestion
• Stomach acids now chyme
• Physical digestion
• Muscle contractions
• Sphincters controls movement
• Cardiac from esophagus
• Pyloric to small intestine

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Small Intestine

• Tube
• Carries food from stomach to large intestines
• Last stages of chemical digestion
• Duodenum (first segment)
• Nutrient absorption into blood
• Villi

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Pancreas

• Releases secretions into small intestines
• Aid chemical digestion
• Neutralize stomach acids
• Produces insulin
• Lowers blood sugar

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Task Text Questions

• Practice Questions
• 1, 3 (pg 216)
• 1 (pg 218)
• Section Questions
• 2 (pg 222)

• Using
• Notes
• Textbook
• Section 6.4 6.5

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Stomach Ulcers
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Liver Gall Bladder

• Produces bile to breakdown fats
• Mechanical digestion
• Fats are made smaller
• Chemical bonds not broken
• Detoxifies toxins
• Gall bladder
• Stores bile for liver

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Large Intestine Colon

• Tube
• Carries wastes from small intestines to anus
• For elimination / egestion
• Colon
• Largest segment
• Wastes are stored
• Water is reabsorb

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Questions so far?
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Task Text Questions

• Practice Questions
• 1, 2, 4 (pg 224)
• 1 3 (pg 226)
• Section Questions
• 1, 8 (pg 229)

• Using
• Notes
• Textbook
• Section 6.6 6.7

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Story Time!

• Setting
• Stormy seas
• Acid rains
• Dry desert
• Nothing comes out unchanged!!

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What do you remember?

• Label the diagram.
• Try it without your notes first!
• (A) (H) have been removed

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(No Transcript)
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Task Text Questions

• Practice Questions
• 1, 2 (pg 212)
• 1, 3 (pg 216)
• 1 (pg 218)
• 1, 2, 4 (pg 224)
• 1 3 (pg 226)
• Section Questions
• 4, 5 (pg 214)
• 2 (pg 222)
• 1, 8 (pg 229)

• Using
• Notes
• Textbook
• Section 6.3 to