Digestive SystemDigestive System

What is digestion and where does it What is digestion and where does it start?start?

The Digestive SystemThe Digestive System

DigestionDigestion

AbsorptionAbsorption

EliminationElimination

DigestionDigestion

Mechanical break down of foodsMechanical break down of foods Teeth-break down food into small piecesTeeth-break down food into small pieces

Masticaiton—process of chewingMasticaiton—process of chewing

Chemical break down of foodsChemical break down of foods Saliva-produced by the salivary glands; the first Saliva-produced by the salivary glands; the first

juices used in the process; break down starches juices used in the process; break down starches and sugars in foods; lubricates food making it and sugars in foods; lubricates food making it easier to swallow.easier to swallow.

Both for use by the cells of the bodyBoth for use by the cells of the body

DigestionDigestion

Chemical break down of foodsChemical break down of foods Saliva-produced by the salivary glands; the Saliva-produced by the salivary glands; the

first juices used in the process; break down first juices used in the process; break down starches and sugars in foods; lubricates starches and sugars in foods; lubricates food making it easier to swallow.food making it easier to swallow.

BileBile Stomach acidsStomach acids EnzymesEnzymes PepsinPepsin

DigestionDigestion

TongueTongue

Forms chewed food into a size and shape that can Forms chewed food into a size and shape that can be easily swallowedbe easily swallowed

EsophagusEsophagus

10” muscular tube that connects the pharynx with 10” muscular tube that connects the pharynx with the stomachthe stomach

DigestionDigestion

PeristalsisPeristalsis A series of involuntary muscle contractions A series of involuntary muscle contractions

that move food through the digestive tractthat move food through the digestive tract EsophagusEsophagus StomachStomach intestinesintestines

DigestionDigestion

StomachStomach Hollow, sac-like organ surrounded by Hollow, sac-like organ surrounded by

muscles which allow for expansion during muscles which allow for expansion during ingestion.ingestion.

3 Jobs3 Jobs Mix foods with gastric juicesMix foods with gastric juices Store swallowed food and liquidStore swallowed food and liquid Move food into small intestineMove food into small intestine

stomachstomach

Mix food with juices:Mix food with juices: Secretions from the stomach lining that Secretions from the stomach lining that

contain HYDROCHLORIC ACID,& PEPSIN, contain HYDROCHLORIC ACID,& PEPSIN, an enzyme that breaks down proteinsan enzyme that breaks down proteins HCL—kills bacteria in food and creates an acidic HCL—kills bacteria in food and creates an acidic

environment for the pepsin to do its jobenvironment for the pepsin to do its job Mucus in the lining of the stomach protects the Mucus in the lining of the stomach protects the

stomach from being digested in its own juicesstomach from being digested in its own juices

stomachstomach

ChymeChyme

The creamy fluid mixture of food and gastric The creamy fluid mixture of food and gastric juices formed in the stomach.juices formed in the stomach.

YUCK!!! But it is what it is!!! :~)YUCK!!! But it is what it is!!! :~)

Indirect Digestive OrgansIndirect Digestive Organs

PancreasPancreas

LiverLiver

Gall BladderGall Bladder

pancreaspancreas Organ that produces enzymes that break down Organ that produces enzymes that break down

the carbohydrates, fats, and proteins we the carbohydrates, fats, and proteins we consume.consume.

Organ that is essential in insulin (blood sugar Organ that is essential in insulin (blood sugar regulator) control.—Diabetes I and II.regulator) control.—Diabetes I and II.

liverliver

Organ that produces bileOrgan that produces bile Yellow-green fluid that helps break down Yellow-green fluid that helps break down

and absorb fatsand absorb fats

Jaundice—when the liver is not functioning Jaundice—when the liver is not functioning properly the skin and eyes can become properly the skin and eyes can become yellow from an excess of bile in the system.yellow from an excess of bile in the system.

gall bladdergall bladder

Connects liver to digestive tract as a gateway Connects liver to digestive tract as a gateway for the bilefor the bile

You can live without, but fatty foods will affect You can live without, but fatty foods will affect the body more than a body with a gall bladder.the body more than a body with a gall bladder.

Can become filled with painful gall stonesCan become filled with painful gall stones

AbsorptionAbsorption

Passage of digested food from the Passage of digested food from the digestive tract into the cardiovascular digestive tract into the cardiovascular system through capillaries in the villi of system through capillaries in the villi of the intestinesthe intestines

absorptionabsorption

Small IntestineSmall Intestine 20-23’ long20-23’ long 1” diameter1” diameter Finishes digestion and begins absorption in the villiFinishes digestion and begins absorption in the villi

—finger-like projections in intestines—finger-like projections in intestines

Large Intestine (colon)Large Intestine (colon) 5-6’ long5-6’ long 2.5” diameter2.5” diameter Finishes absorption and begins eliminationFinishes absorption and begins elimination

EliminationElimination Expulsion of undigested food or body wastesExpulsion of undigested food or body wastes

Begins with large intestine—eliminate fecesBegins with large intestine—eliminate feces

Skin excretes some wastes through the pores—sweatingSkin excretes some wastes through the pores—sweating

Lungs expel CO2 and other gas wastesLungs expel CO2 and other gas wastes

Liquids are filtered to the urinary tract for expulsionLiquids are filtered to the urinary tract for expulsion