© 2006 Plano ISD, Plano, TX

© 2006 Plano ISD, Plano, TX

Digestive SystemDigestive System

a coiled, muscular tube (6-9 meters long) beginning with the mouth and ending with the anus

© 2006 Plano ISD, Plano, TX

DigestionDigestion

process by which food is converted into soluble forms

2 forms of digestion2 forms of digestion

physicalphysical chemicalchemical

© 2006 Plano ISD, Plano, TX

Forms of DigestionForms of Digestion

Physical DigestionPhysical

Digestion

begins in mouth with saliva mostly occurs in small intestine

Chemical DigestionChemical Digestion

begins in mouth by chewing

mechanical breakdown of food into smaller particles

increases surface area of food

chemical breakdown of food by enzymes

© 2006 Plano ISD, Plano, TX

Physical DigestionPhysical

Digestion

begins in mouth with saliva

Chemical DigestionChemical Digestion

begins in mouth by chewing

mechanical chemical

© 2006 Plano ISD, Plano, TX

Stages of DigestionStages of Digestion

secretion

digestion

absorption

elimination

propels food through system

movementrelease of digestive juicesbreakdown of food into molecular sizes

food molecules passing through intestinal walls

removal of undigested food

© 2006 Plano ISD, Plano, TX

Primary Digestive Organs

Primary Digestive Organs

© 2006 Plano ISD, Plano, TX

teethteeth

tonguetongue

begin the mechanical breakdown of food

begin the mechanical breakdown of food - transports

food to stomach through the process of peristalsis

- transports food to stomach through the process of peristalsis - muscular organ that stores, mixes, digests and controls passage of food

- muscular organ that stores, mixes, digests and controls passage of food

mouthmouth

esophagusesophagus

stomachstomach

© 2006 Plano ISD, Plano, TX

PeristalsisPeristalsis

stomachstomach

series of involuntary muscular contractions in the

esophagus that

squeeze the food down to

the stomach

series of involuntary muscular contractions in the

esophagus that

squeeze the food down to

the stomach

foodfood

esophagusesophagus

© 2006 Plano ISD, Plano, TX

A gastric chief cell (or peptic cell, or gastric zymogenic cell) is a cell

in the stomach that releases pepsinogen, gastric lipase and

chymosin.[

© 2006 Plano ISD, Plano, TX

Parietal cells (also called oxyntic cells) are the stomach epithelium cells which secrete hydrochloric

acid

© 2006 Plano ISD, Plano, TX

- coiled tube from 3 - 6m long, the major site for digestion and absorption of nutrients; contain villi

- coiled tube from 3 - 6m long, the major site for digestion and absorption of nutrients; contain villi

small intestines small intestines

- 1.5 m long tube, absorbs water from undigested material

- 1.5 m long tube, absorbs water from undigested material anusanus - opening for removal of feces - opening for removal of feces

large intestineslarge intestines

© 2006 Plano ISD, Plano, TX

Accessory Digestive Organs

Accessory Digestive Organs

© 2006 Plano ISD, Plano, TX

- produces bile, which helps break down fats in small intestines

- produces bile, which helps break down fats in small intestines

- secretes enzymes that break down starches and proteins

- secretes enzymes that break down starches and proteins

- stores bile- stores bile

salivary glands salivary glands

- secrete a chemical (enzyme) that breaks down starch into glucose

- secrete a chemical (enzyme) that breaks down starch into glucose

pancreaspancreas

gall bladdergall bladder

liverliver

© 2006 Plano ISD, Plano, TX

Accessory Digestive OrgansAccessory Digestive Organsconnected to stomach by

ductsconnected to stomach by

ducts

liverliver

pancreaspancreas

gall bladdergall bladder

© 2006 Plano ISD, Plano, TX

© 2006 Plano ISD, Plano, TX

ulcersulcers spot in stomach lining where cells are destroyed, lining unprotected, irritated by stomach acid

gastritisgastritis

swelling of stomach lining, caused by irritating foods, alcohol, or bacteria

acid refluxacid reflux

"back washing" of acid from the stomach into the esophagus; also called heartburn

© 2006 Plano ISD, Plano, TX

© 2006 Plano ISD, Plano, TX

1.

2.

3.

4.

5.6.7.8.9.10.

© 2006 Plano ISD, Plano, TX

1. mouth1. mouth1.1.

2.2.2. esophagus2. esophagus

3.3.3. stomach3. stomach

4.4.4. small intestine4. small intestine5.5.5. large intestine5. large intestine

6.6.6. anus6. anus

© 2006 Plano ISD, Plano, TX

1.1.

2.2.

3.3.

4.4.

salivary glandssalivary glands

liverliver

gall bladdergall bladder

pancreaspancreas

© 2006 Plano ISD, Plano, TX

1.1.

2.2.

3.3.

4.4.

5.5.

6.6.

© 2006 Plano ISD, Plano, TX

1.1.

2.2.

3.3.

4.4.

© 2006 Plano ISD, Plano, TX

stomachstomachanusanusesophagusesophagussalivary glands

salivary glandsliverliversmall

intestinesmall

intestinepancreaspancreaslarge intestine

large intestine

gall bladder

gall bladder

Match the structure with the

number.

Match the structure with the

number.

© 2006 Plano ISD, Plano, TX

Match the function with the

number.

Match the function with the

number.

produces bileproduces bilestores undigestible food

stores undigestible foodcontains villicontains villimixes and stores food

mixes and stores food

contains enzymes for the first

chemical breakdown of food

contains enzymes for the first

chemical breakdown of food

the 4 accessory digestive organs

the 4 accessory digestive organs

secretes enzymes for starch

breakdown

secretes enzymes for starch

breakdown

transports food by peristalsis

transports food by peristalsis

major organ for digestion and absorption of

nutrients

major organ for digestion and absorption of

nutrients

stores bilestores bile

© 2006 Plano ISD, Plano, TX

• http://nature.ca/discover/exm/blddgstvsystm/index_e.cfm