digestive system chemical digestion of food

Digestive SystemDigestive SystemChemical Digestion of FoodChemical Digestion of Food

Submaxillary

Gland

The Small Intestine.The Small Intestine.

It is a tube 3cm in diameter and 7m long.It is a tube 3cm in diameter and 7m long.

The small intestine is divided into three The small intestine is divided into three parts:parts:

• Duodenum – 1Duodenum – 1stst 25cm 25cm• Jejunum – 2m longJejunum – 2m long• Ileum – 5m longIleum – 5m long

The Large Intestine or ColonThe Large Intestine or Colon

Tube 7cm in diameter.Tube 7cm in diameter.

1 1/2m long1 1/2m long

An upside down “U”An upside down “U”

Sugars – The Simplest Carbohydrates.Sugars – The Simplest Carbohydrates.

Monosaccharides are the simple (single sugars)Monosaccharides are the simple (single sugars)

ExEx.: Glucose, Fructose, and Galactose..: Glucose, Fructose, and Galactose.

Disaccharides are composed of two monosaccharides Disaccharides are composed of two monosaccharides linked together.linked together.

ExEx.: Glucose + glucose.: Glucose + glucose Maltose Maltose Glucose + fructose Glucose + fructose Sucrose Sucrose

Sugars – the simplest sugars Sugars – the simplest sugars (continued)(continued)

Polysaccharides are composed of many Polysaccharides are composed of many monosaccharides joined together into long monosaccharides joined together into long chains.chains.

ExEx.:.:glucose + glucose + glucose + glucose glucose + glucose + glucose + glucose Starch Starch

(there could be hundreds of monosaccharides joined (there could be hundreds of monosaccharides joined together).together).

Other examples of polysaccharides are: glycogen Other examples of polysaccharides are: glycogen (animal starch), cellulose, and pectin (can not be (animal starch), cellulose, and pectin (can not be digested in humans)digested in humans)

Mod

ern

Bio

logy

, 19

87

Carbohydrates

Carbohydrates - Starches

Proteins

Chains of Amino Acids

Fats (Lipids)

Digestion of CarbohydratesDigestion of Carbohydrates

Digestion of ProteinDigestion of Protein

Digestion of FatsDigestion of Fats

Digestion in HumansDigestion in Humans

OrganOrgan Major Physical Major Physical ActivitiesActivities

Major Chemical ActionMajor Chemical Action

Mouth Mouth

ChewingChewing

GrindingGrinding

MoisteningMoistening

StarchStarch→ Disaccharide→ Disaccharide

amyl

ase

amyl

ase

Digestion in HumansDigestion in Humans

OrganOrgan Major Major Physical Physical ActivitiesActivities

Major Chemical ActionMajor Chemical Action

EsophagusEsophagus PersistalsisPersistalsis

MoisteningMoistening

NoneNone

Digestion in HumansDigestion in Humans

OrganOrgan Major Physical Major Physical ActivitiesActivities

Major Chemical ActionMajor Chemical Action

StomachStomach

MoisteningMoistening

ChurningChurning

PeristalsisPeristalsis

TwistingTwisting

Proteins → Smaller Chains Proteins → Smaller Chains

of Amino Acidsof Amino Acids

peps

inpe

psin

Digestion in HumansDigestion in HumansOrganOrgan Major Physical Major Physical

ActivitiesActivitiesMajor Chemical ActionMajor Chemical Action

Small Small Intestine Intestine

PeristalsisPeristalsis

Fat Fat EmulsificationEmulsification

Most nutrient Most nutrient ABSORPTIONABSORPTION

From Pancreas: From Pancreas:

StarchStarch→ Disaccharide→ Disaccharide

Proteins → SmallerProteins → Smaller

Chains of A.A.Chains of A.A.am

ylas

e

amyl

ase

tryps

intry

psin

Digestion in HumansDigestion in HumansOrganOrgan Major Physical Major Physical

ActivitiesActivitiesMajor Chemical ActionMajor Chemical Action

Small Small Intestine Intestine

(cont’d)(cont’d)

Smaller Chains Smaller Chains → Free→ Free

Of A.A.Of A.A. A.A. A.A.

Fats → Fatty acids and Fats → Fatty acids and

glycerol glycerol

erep

sin

erep

sin

lipas

elip

ase

Digestion in HumansDigestion in HumansOrganOrgan Major Physical Major Physical

ActivitiesActivitiesMajor Chemical ActionMajor Chemical Action

Small Small Intestine Intestine

(cont’d)(cont’d)

Dis’rides Dis’rides → Monos’rides → Monos’rides

Maltose → GlucoseMaltose → Glucose

en

zym

e

enzy

me

mal

tase

mal

tase

Digestion in HumansDigestion in HumansOrganOrgan Major Physical Major Physical

ActivitiesActivitiesMajor Chemical ActionMajor Chemical Action

Small Small Intestine Intestine

(cont’d)(cont’d)

Lactose Lactose → Glucose → Glucose

Sucrose → GlucoseSucrose → Glucose

la

ctas

ela

ctas

e

sucr

ase

sucr

ase

Digestion in HumansDigestion in HumansOrganOrgan Major Physical Major Physical

ActivitiesActivitiesMajor Chemical ActionMajor Chemical Action

Large Large Intestine Intestine

PeristalsisPeristalsis

Water Water AbsorptionAbsorption

Waste Waste EliminationElimination

Some vitamins (B12) are Some vitamins (B12) are synthesized here.synthesized here.

Ho

w Y

ou

r B

od

y W

ork

s, p

. 11

8

How the Body Works, p. 119

How Your Body Works, p. 116.

How Your Body Works, p. 116