Human Body

Digestive System

Functions

1.Break down food (digest)

2.Take in food (ingest)

3.Absorb nutrients from food

4.Eliminate (get rid of) solid waste

DIGESTION• The process of breaking

down food into a form that the body can use

• Large molecules into smaller ones!

2 Types of digestion

Mechanical

and Chemical

Mechanical Digestion

Food is chewed, mixed and churned. Takes place in the mouth and stomach

Chemical DigestionChemical reactions that break down large molecules into smaller molecules that can be absorbed by cells Examples: saliva in mouth

acids & enzymes

ORGANSMajor Organs:

Mouth

Esophagus

Stomach

Small Intestine

Large Intestine

Rectum

Anus

Accessory Organs:

• Tongue

• Teeth

• Salivary Glands

• Liver

• Gallbladder

• Pancreas

Mouth1. Digestion begins

2. Mechanical (teeth and tongue) & Chemical (saliva) digestion

3. Saliva mixes with food to produce a soft mass called a Bolus

Esophagus

1. No digestion takes place

2. Peristalsis-muscle contractions (squeezing) that helps move food down the esophagus and through the digestive tract

Stomach

1. Mechanical (churning) and chemical digestion2. Produces HCl (hydrochloric acid)

and mucus

3. Becomes a substance

called chyme (kime),

A thin watery product

Small Intestine1. Major portion of all digestion

occurs in the duodenum

2. Digestive juices from the liver, gall bladder (bile) and pancreas are added

3. Villi-make the surface larger so there are more places for food and nutrients to be absorbed

VILLI

Real above

Scientific illustration right

Large Intestine

1. Absorbs water from the chyme

2. Chyme may stay in the large intestine for up to 3 days

Rectum and Anus

Chyme makes its way out of the body, usually as “solid” waste… compacted in the rectum and expelled from the anus.