The Digestive SystemThe Digestive SystemFood, Food, Food is the WordFood, Food, Food is the Word

FunctionFunction

1.1. To break down food into smaller To break down food into smaller molecules (nutrients) that the body can molecules (nutrients) that the body can useuse

– Carbohydrates Carbohydrates Simple Sugars Simple Sugars

– Proteins Proteins Amino Acids Amino Acids

– Fats Fats Glycerol and Fatty Acids Glycerol and Fatty Acids

2.2. To get rid of To get rid of solidsolid wastes that remain wastes that remain after nutrients have been extractedafter nutrients have been extracted

Types of DigestionTypes of Digestion

• Mechanical:Mechanical:–PHYSICAL breakdown of foodPHYSICAL breakdown of food

• EX.EX. Chewing Chewing• Chemical:Chemical:

–CHEMICAL breakdown of food by CHEMICAL breakdown of food by enzymes or other digestive juicesenzymes or other digestive juices• EX:EX: Amylase found in saliva breaks Amylase found in saliva breaks down Carbsdown Carbs

The Path of DigestionThe Path of Digestion

MouthMouth

EsophagusEsophagus

StomachStomach

Small IntestineSmall Intestine

Large IntestineLarge Intestine

PancreasPancreasLiverLiver

Gall BladderGall Bladder

Accessory Organs

Path of Digestion: MouthPath of Digestion: Mouth

• Begins the breakdown of foodBegins the breakdown of food• Types of Digestion:Types of Digestion:

– Mechanical:Mechanical:• Chewing (Teeth and Tongue)Chewing (Teeth and Tongue)

– Chemical:Chemical:• Saliva that contains enzymesSaliva that contains enzymes

• Molecules that are digested:Molecules that are digested:– CarbohydratesCarbohydrates (Enzyme = Amylase) (Enzyme = Amylase)

Swallowing Animation

Path of Digestion: EsophagusPath of Digestion: Esophagus• Brings food from mouth to stomachBrings food from mouth to stomach

– Food is now called a Food is now called a BOLUSBOLUS

• Epiglottis:Epiglottis:

– Flap of tissue at back of throat that Flap of tissue at back of throat that prevents food from entering the wind-prevents food from entering the wind-pipepipe

• Peristalsis:Peristalsis:

– Wave-like contractions that move bolus Wave-like contractions that move bolus to stomach to stomach

Click Here for animation

Path of Digestion: StomachPath of Digestion: Stomach• Further breaks down bolus for nutrient Further breaks down bolus for nutrient

extractionextraction• Types of Digestion:Types of Digestion:

– ChemicalChemical Digestion: Digestion:• Gastric juices (Gastric juices (VERY ACIDICVERY ACIDIC) )

containing enzymes breakdown:containing enzymes breakdown:–Continued digestion of CarbohydratesContinued digestion of Carbohydrates–First First PROTEINPROTEIN digestion digestion

– MechanicalMechanical Digestion: Digestion:• Churn, Churn, Churn!Churn, Churn, Churn!

• Bolus turned to Bolus turned to CHYMECHYME

Path of Digestion: Small IntestinePath of Digestion: Small Intestine

• Further breaks down chyme for nutrient Further breaks down chyme for nutrient absorption by blood streamabsorption by blood stream– S.I. lined with tiny projections called S.I. lined with tiny projections called VILLIVILLI– Villi contain capillaries that absorb nutrients Villi contain capillaries that absorb nutrients

into blood streaminto blood stream– Nutrients move into blood stream by what Nutrients move into blood stream by what

process (Think H to L!)?process (Think H to L!)?• DIFFUSION!!!!!!!!!DIFFUSION!!!!!!!!!

• Type of digestion:Type of digestion:– Chemical Only:Chemical Only:

• Continued digestion of CarbohydratesContinued digestion of Carbohydrates• Continued digestion of ProteinsContinued digestion of Proteins• First First FATFAT digestion digestion

Helper Organs: The Video ClipHelper Organs: The Video Clip

Helper (Accessory) OrgansHelper (Accessory) Organs• Food Food DOES NOTDOES NOT pass through these organs pass through these organs• These organs These organs secretesecrete substances to aid in substances to aid in

digestiondigestion• Pancreas:Pancreas:

– Secretes enzymes into S.I for digestionSecretes enzymes into S.I for digestion– Secretes a base into S.I. to neutralize stomach acid Secretes a base into S.I. to neutralize stomach acid

WHY??WHY??• So digestive enzymes aren’t denatured and can work!So digestive enzymes aren’t denatured and can work!

• Liver:Liver:– Produces and secretes Produces and secretes BILEBILE that breaks down fats that breaks down fats

• Gall Bladder:Gall Bladder:– Stores the bileStores the bile

Path of Digestion: Large IntestinePath of Digestion: Large Intestine

• Removes Removes WATERWATER from undigested chyme from undigested chyme

• Lined with bacteria (Lined with bacteria (E. coli) E. coli)

• Proper water absorption is necessary to Proper water absorption is necessary to keep you regular!keep you regular!– Not enough water absorbed = Not enough water absorbed = DIARRHEADIARRHEA– Too much water absorbed = Too much water absorbed = CONSTIPATIONCONSTIPATION

• Final stop for undigested material…the Final stop for undigested material…the anus!anus!

Digestive System Fill-InDigestive System Fill-In

Digestive System Fill-In AnswersDigestive System Fill-In Answers