Digestive System Ms. Lowrie Biology 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 Intestine Small 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)