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22-3 Your Digestive System

-What organs make up your digestive system??

-What is the path that food Travels in your body??

Digestion

• Process of breaking down food into small molecules that can be used for energy

• Not all food is used for energy.

Mechanical vs. Chemical Digestion

• Mechanical= food is broken down into smaller pieces– Done in the mouth and stomach

• Chemical = large molecules are broken down into smaller molecules through changes by different chemicals– Molecules will be absorbed after this – Found in mouth, stomach, + small intestine

• Both of these are used to release energy for the body

• Major organs for this process are:–Mouth– Esophagus– Stomach– Small Intestine– Large Intestine–Rectum–Anus

Your Mouth

• JOB- food is cut into smaller pieces • mechanical and chemical digestion occurs

here.

Esophagus

• JOB- connect mouth and stomach• Basically is a long tube (25 cm) that connects

the stomach to the mouth.

• Peristalsis- – waves of contractions by smooth muscles, move

the food through the esophagus.

Stomach• JOB= Food is turned into a soup (chyme)

• Mechanical (turns food)• Chemical digestion (enzymes and acid) occurs

• Changes shape- when empty- is a long tube (hotdog/sausage), when full- expands in size.

• Has Stomach Acid– Is very acidic- pH = 9, is Hydrochloric acid-– would eat away your stomach, but the

stomach has lining to not let happen

• Food stays here for about 4 hrs.

Small Intestine

• JOB = Food is absorbed here• Is very long (4m to 7m)• Pancreas, liver, and gallbladder release enzymes

into the small intestine

• Inside of the small intestine has many ridges and folds= villi–This allows the food to be absorbed by the

blood

Large Intestine

• Job= to absorb water from the chyme, causing chyme to turn to a solid form

• Chyme may stay in the large intestine up to 3 days to get the job done

Rectum + Anus

• Rectum-– Waste is stored here temporarily tell expelled

• Anus-– Waste leaves the body here

Minor Organs

• Appendix• Liver• Pancreas• Gall Bladder• Teeth• Salivary Glands• Tongue

• Teeth– Cut/Tear food into smaller piece

• Salivary Glands– Make and store saliva

• Tongue– Moves the food around and helps a person talk

• Liver– Makes bile

• Gall Bladder– Stores Bile– Found hidden in the liver

• Pancreas– Releases juices into the small intestine to

breakdown and help food be absorbed– Hidden behind your stomach

• Appendix– Stores bacteria– Located off the large intestine

What are Enzymes?

What is the role of Enzymes in our body??

Can anyone name a few examples of enzymes in the body.

Enzymes

• These are molecules that speed up reactions in our body

• Can reduce amount of energy needed or provide a place for the reaction to occur

• Enzymes also help build molecules (besides just breaking them down)– Used in blood clots– Found in Muscle and nervous systems

• Humans couldn’t exist if they didn’t have enzymes.

• Saliva-–has amylase- • this starts the break down

carbohydrates

• Stomach-–has pepsin- • this starts the break down of proteins

Enzymes

-Insulin- -Released by the pancreas, -Allows glucose to be absorbed in the blood

• Bile – Released by gallbladder – helps breakdown fats

Food Absorption

• Peristalsis helps food continue to move throughout the digestive tract

• Food molecules will start to move into the bloodstream by diffusion, osmosis, and active transportation

• Once in the bloodstream they will go throughout the body- giving it energy

Good Bacteria in the Body

• Bacteria are heavily found in the large intestine.

• They break down cellulose (carbohydrate found in plants)– releasing several vit. and minerals

• Bacteria and humans have a mutualism relationship

The End