Digestive System. Organs of the Digestive System Mouth Mouth Esophagus Esophagus Stomach Stomach Small Intestine Small Intestine Large Intestine Large

Digestive Digestive SystemSystem

Organs of the Digestive Organs of the Digestive SystemSystem

MouthMouth EsophagusEsophagus StomachStomach Small IntestineSmall Intestine Large IntestineLarge Intestine RectumRectum AnusAnus

Functions of the Functions of the Digestive SystemDigestive System

1.1. IngestionIngestion = Food = Food

enters the mouth.enters the mouth.


1.1. IngestionIngestion = Food enters the = Food enters the

mouth.mouth.

2.2. DigestionDigestion = =

Process that Process that breaksbreaks

food food downdown into into

small molecules thatsmall molecules that

can be used by cellscan be used by cells


1.1. IngestionIngestion = Food enters the = Food enters the mouth.mouth.

2.2. DigestionDigestion = Process that = Process that breaks food down into small breaks food down into small molecules that can be used by cellsmolecules that can be used by cells

a)a) MechanicalMechanical digestion = digestion = Food is chewed, mixed, Food is chewed, mixed, or churned.or churned.

b)b) ChemicalChemical digestion = digestion = Breaks down large food Breaks down large food molecules using chemicalmolecules using chemicalreactionsreactions


1.1. IngestionIngestion = Food enters the = Food enters the

mouth.mouth.

2.2. DigestionDigestion = Process that = Process that

breaks food down into small breaks food down into small

molecules that can be used by molecules that can be used by

cellscells

3.3. AbsorptionAbsorption = =

Small molecules of Small molecules of

food are moved intofood are moved into

thethe bloodstream. bloodstream.


1.1. IngestionIngestion = Food enters the = Food enters the mouth.mouth.

2.2. DigestionDigestion = Process that = Process that breaks food down into small breaks food down into small molecules that can be used by cellsmolecules that can be used by cells

3.3. AbsorptionAbsorption = Small = Small molecules of food are movedmolecules of food are moved

into the bloodstream.into the bloodstream.

4.4. EliminationElimination = = WastesWastes made of made of unabsorbed food unabsorbed food molecules pass out of the body.molecules pass out of the body.

Large Intestine

Which is not a function Which is not a function of the digestive of the digestive

system?system?a)a) Breaking down food into Breaking down food into

molecules the body cells molecules the body cells can usecan use

b)b) Absorbing food molecules Absorbing food molecules into the blood to deliver into the blood to deliver to the body cellsto the body cells

c)c) Changing waste into Changing waste into molecules the body can molecules the body can useuse

d)d) Eliminating undigested Eliminating undigested waste from the bodywaste from the body

Organs of the Organs of the Digestive TractDigestive Tract

1.1. MouthMouth = = Digestion starts Digestion starts here.here.



a)a) The tongue & teeth The tongue & teeth mechanicallymechanically break food up.break food up.



a)a) The tongue & teeth The tongue & teeth mechanicallymechanically break food up.break food up.

b)b) Saliva Saliva chemicallychemically digests food. digests food.a)a) SalivaSaliva = Mostly made of = Mostly made of

waterwater, also contains mucus, also contains mucus

and enzymes, which break and enzymes, which break food molecules down with food molecules down with chemical reactions.chemical reactions.


1.1. MouthMouth = = Digestion starts here.Digestion starts here.a)a) The tongue & teeth The tongue & teeth mechanicallymechanically

break food up.break food up.b)b) Saliva Saliva chemicallychemically digests food. digests food.

a)a) SalivaSaliva = Mostly made of = Mostly made of waterwater, also contains , also contains mucus and enzymes, which break mucus and enzymes, which break food down with chemical food down with chemical reactionsreactions

c)c) When swallowing, the When swallowing, the epiglottis epiglottis (a small flap of tissue) automatically (a small flap of tissue) automatically closes over the closes over the tracheatrachea (windpipe). (windpipe).


2.2. EsophagusEsophagusa)a) SmoothSmooth muscles force food into muscles force food into

the mucus-lined esophagus.the mucus-lined esophagus.

b)b) Rhythmic muscular Rhythmic muscular

contractions contractions

((peristalsisperistalsis) push food ) push food

downwarddownward..


3.3. StomachStomacha)a) Food undergoes Food undergoes mechanicalmechanical digestion digestion

when stomach muscles when stomach muscles churnchurn the food the food into into chymechyme, a soupy substance., a soupy substance.

b)b) ChemicalChemical digestion digestion happens when hydrochloric happens when hydrochloric acid (acid (HClHCl) and ) and pepsinpepsin break down the complex break down the complex proteins.proteins.

3.3. PeristalsisPeristalsis pushes the chyme pushes the chyme toward stomachtoward stomach’’s exit after s exit after 2-42-4 hours. hours.

Which is not an Which is not an example of mechanical example of mechanical digestion?digestion?a)a) Teeth chewing foodTeeth chewing food

b)b) Tongue breaking up Tongue breaking up foodfood

c)c) Smooth muscles in Smooth muscles in stomach churning stomach churning foodfood

d)d) Hydrochloric acid Hydrochloric acid breaking down breaking down proteinsproteins


4.4. Small IntestineSmall Intestine (4-7 meters (4-7 meters long)long)

a)a) Mechanical & Chemical Mechanical & Chemical digestion happen here.digestion happen here.

b)b) Intestinal juice Intestinal juice

(full of (full of enzymesenzymes) )

breaks down food.breaks down food.




b)b) Intestinal juice (full of Intestinal juice (full of enzymesenzymes) breaks down ) breaks down food.food.

c)c) Accessory OrgansAccessory Organs• LiverLiver = = BileBile is is

produced here (Bileproduced here (Bile

breaks upbreaks up fatsfats like like

dish detergent dish detergent

breaks up grease.).breaks up grease.).

Organs of the Digestive Organs of the Digestive TractTract



b)b) Intestinal juice (full of Intestinal juice (full of enzymesenzymes) breaks down ) breaks down food.food.

c)c) Accessory OrgansAccessory Organs• LiverLiver = = BileBile is produced is produced

here (Bilehere (Bile breaks upbreaks up fatsfats

like dish detergent breaks like dish detergent breaks

up grease.).up grease.).

4.4. Gall bladderGall bladder = Bile = Bile

is is storedstored here until here until

released into the small intestine.released into the small intestine.


4.4. Small IntestineSmall Intestine (4-7 meters long)(4-7 meters long)a)a) Mechanical & Chemical Mechanical & Chemical digestion happen here.digestion happen here.b)b) Intestinal juice (full of Intestinal juice (full of enzymesenzymes) breaks down food.) breaks down food.

c)c) Accessory OrgansAccessory Organs• LiverLiver = = BileBile is produced is produced

here (Bilehere (Bile breaks up breaks up fatsfats like dish detergent breaks like dish detergent breaks up grease.).up grease.).

4.4. Gall bladderGall bladder = Bile is = Bile is storedstored here until released here until released into the small intestine.into the small intestine.

a)a) PancreasPancreas = Produces = Produces pancreatic juices, like insulin, that pancreatic juices, like insulin, that are released into the small intestine to are released into the small intestine to break down break down starchesstarches


4.4. Small IntestineSmall Intestine (4-7 meters long)(4-7 meters long)a)a) Mechanical & Chemical Mechanical & Chemical digestion happen digestion happen

here.here.b)b) Intestinal juice (full of Intestinal juice (full of

enzymesenzymes) breaks down food.) breaks down food.c)c) Accessory OrgansAccessory Organs

• LiverLiver • Gall bladderGall bladder• PancreasPancreas

d)d) Digested food is Digested food is absorbed absorbed through the through the villi, villi, ridgesridges in the small in the small intestine, into capillaries that carry intestine, into capillaries that carry the nutrients to all of the the nutrients to all of the body cellsbody cells..



a)a) Mechanical & Chemical Mechanical & Chemical digestion happen digestion happen here. here.

b)b) Intestinal juice (full of Intestinal juice (full of enzymesenzymes) ) breaks down food.breaks down food.

c)c) Accessory OrgansAccessory Organs• Liver,Liver, Gall bladder, PancreasGall bladder, Pancreas

d)d) Digested food is Digested food is absorbedabsorbed through the through the villivilli into capillaries that carry into capillaries that carry the nutrients to all of the the nutrients to all of the body cells.body cells.

e) By the time food leaves the small e) By the time food leaves the small intestine, it is intestine, it is emptyempty of all of all nutrients except nutrients except waterwater..

Where does absorption Where does absorption of nutrients take of nutrients take

place?place?a)a) MouthMouth

b)b) StomachStomach

c)c) Small intestineSmall intestine

d)d) Liver Liver


5.5. Large IntestineLarge Intestine (1.5 meters (1.5 meters long)long)

a)a) Undigested food spends Undigested food spends 18–2418–24 hours hours here, and most of the water is here, and most of the water is re-absorbedre-absorbed. This . This waste material is now waste material is now called feces.called feces.


5. 5. Large IntestineLarge Intestine (1.5 meters (1.5 meters long)long)

a)a) Undigested food spends Undigested food spends 18–2418–24 hours here, and hours here, and most of the water is most of the water is re-absorbedre-absorbed..

b)b) Helpful Helpful bacteriabacteria

living in the large living in the large

intestine make intestine make

vitamins vitamins BB and and KK..


5.5. Large Intestine Large Intestine (1.5 meters long)(1.5 meters long)a)a) Undigested food spends Undigested food spends 18–2418–24 hours here, and most hours here, and most

of the water is of the water is re-absorbedre-absorbed..b)b) Helpful Helpful bacteriabacteria living in the living in the

large intestine make vitamins large intestine make vitamins BB and and KK..

Materials not Materials not absorbed form into absorbed form into solid wastesolid waste (dead (dead bacteriabacteria, some , some fatfat and and proteinprotein, undigested , undigested food, dried out parts of food, dried out parts of digestive juices, and old intestinal digestive juices, and old intestinal cellscells).).


5.5. Large Intestine Large Intestine (1.5 meters long)(1.5 meters long)a)a) Undigested food spends Undigested food spends 18–2418–24 hours here, and most of the hours here, and most of the

water is water is re-absorbedre-absorbed..

b)b) Helpful Helpful bacteriabacteria living in the large living in the large

intestine make vitamins intestine make vitamins BB and and KK.. Materials not absorbed form into Materials not absorbed form into

solid waste solid waste (dead (dead bacteriabacteria, ,

some some fatfat & & proteinprotein, undigested , undigested

food, dried out parts of digestive food, dried out parts of digestive

juices, and old intestinal juices, and old intestinal cellscells).).

Solid waste passes Solid waste passes

into the into the rectumrectum and is stored until it is and is stored until it is eliminated from the body through the eliminated from the body through the anusanus..


6. 6. Large Intestine Large Intestine (1.5 meters (1.5 meters long)long)

Attached to the large intestine is aworm-like structure called the appendix.Little is understood about the function ofthe appendix. The function of the appendix is unknown. One theory is that the appendix acts as a storehouse for good bacteria, “rebooting” the digestive system after illnesses. Other experts believe the appendix played a part in thedigestion of early-man’s diet.

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Digestive System. Organs of the Digestive System Mouth Mouth Esophagus Esophagus Stomach Stomach Small Intestine Small Intestine Large Intestine Large