Digestive SystemBreaking down food to be used by

the body

Mouth

1.Mechanical Digestion – break up of food=chewing

2.Beginning of Chemical Digestion

Saliva from Salivary Gland- breaks down starches into simpler sugars

Function

Esophagus

• Food tube- contraction of muscle rings push food to the stomach (Peristalsis)

• Think: Where does food go if it “goes down the wrong pipe?”

Function

Stomach

• Mechanical-Food mixes-becomes Chyme

• Chemical Digestion-

-Mostly digests some proteins

Function

Small Intestine

• MOST nutrient absorption takes place here!

• Enzymes in the small intestine come from the pancreas and liver.

• Basic environment (not acid) helps neutralize acid from stomach.

• As chyme enters: – No fat digestion has taken

place yet!

Function

Liver

• Secretes Bile into beginning of small intestine– Helps to break down

fats by preventing their sticking together so enzymes can attack

– Not an Enzyme!– Works like dish-

washing soap

• The Gall Bladder stores the bile

Function

Chemical Digestion: Fats

Figure 23.35

Like soaping your body!Or the dishes!

Pancreas

• Secretes Sodium Bicarbonate– base that neutralizes

acid in small intestine

• Many chemicals used in digestion come from the pancreas

• All remaining digestion happens in small intestines

Function

Hidden behind stomach

Large Intestine (Colon)

• Removes WATER from undigested material

• What happens when not enough water is removed?

• Some GOOD bacteria live here– Breakdown indigestible

carbohydrates (lactose)– Synthesize B complex

vitamins and vitamin K

Function