Digestive System

Ms. LowrieBiology 11

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

Purpose

Plants=Autotrophs• Make own food

• Photosynthesis

Animals=Heterotrophs• Must eat to survive

• Organic compounds

• Used for energy, growth & repair

Five Functions

1. Ingestion Consuming food Occurs in: mouth

2. Digestion Breaking apart food into a smaller form

Mechanical or chemical

Occurs in: mouth, stomach, small intestine

Five Functions (cont.)

3. Transportation Movement of materials through digestive

tract Occurs by: peristalsis

Wavelike contraction of muscles

Peristalsis

Five Functions (cont.)

4. Absorption Moving nutrients into circulatory system Occurs in: small and large intestines

5. Elimination (Egestion)• Removing undigested or unabsorbed

materials

• Occurs by: rectum (storage) and anus

Digestion:Mechanical 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

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

Are you still hungry?

Task:

Using pages 208 – 226

Label diagram

Complete “Part Chart”• Describe the function(s) of each part

Diagram

Mouth

Salivary Glands

Stomach

Pancreas (behind the stomach)

Large IntestineSmall Intestine

Pharynx

Esophagus

Liver

Gallbladder (behind the liver)

Anus

Salivary Glands

Lubricates food• For swallowing

Activates taste buds Starts breakdown of

carbohydrates

Mouth & Teeth

Mechanical digestion • Including tongue

Food chewed into a bolus• Ball of food

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

Esophagus

Tube Carries food from mouth to stomach Movement regulated by peristalsis

Task – Text Questions

Using: • Notes

• Textbook• Section 6.3

Practice Questions:

• #1, 2 (pg 212)

Section Questions:

• #4, 5 (pg 214)

Stomach

Food storage Chemical digestion

• Stomach acids = now “chyme” Physical digestion

• Muscle contractions

Sphincters controls movement• Cardiac from esophagus

• Pyloric to small intestine

Small Intestine

Tube Carries food from stomach

to large intestines Last stages of chemical

digestion• Duodenum (first segment)

Nutrient absorption into blood• Villi

Pancreas

Releases secretions into small intestines • Aid chemical digestion

• Neutralize stomach acids

Produces insulin• Lowers blood sugar

Task – Text Questions

Using: • Notes

• Textbook• Section 6.4 & 6.5

Practice Questions:

• #1, 3 (pg 216)

• #1 (pg 218)

Section Questions:

• #2 (pg 222)

Stomach Ulcers

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

Large Intestine & Colon

Tube Carries wastes from small

intestines to anus • For elimination / egestion

Colon: • Largest segment

• Wastes are stored

• Water is reabsorb

Questions so far?

Task – Text Questions

Using: • Notes

• Textbook• Section 6.6 & 6.7

Practice Questions:

• #1, 2, 4 (pg 224)

• #1 – 3 (pg 226)

Section Questions:

• #1, 8 (pg 229)

Story Time!

Setting: Stormy seas Acid rains Dry desert

Nothing comes out unchanged!!

What do you remember?

Label the diagram.

• Try it without your notes first!

• (A) & (H) have been removed

Task – Text Questions

Using: • Notes

• Textbook• Section 6.3 to

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)