THE HUMAN BODYThe Digestive System

Mr. Parr Digestion Song

Its Purpose…..Digestion a process where food is broken down into substances that can be used by the cells of the body.

TYPES OF DIGESTIONMECHANICAL

• Occurs when food is broken down into smaller pieces.

CHEMICAL• Occurs when food is

chemically changed into simpler substances that can be used by the body.

Inside the Digestive Tract

• The digestive tract is a series of hollow organs that creates a long tube. There are 5 major stops along the way for digesting food.

• 1. Mouth• 2. Esophagus• 3. Stomach• 4. Small Intestines• 5. Large Intestines

The Digestive Tract

START1. Food enters the mouth. The teeth chop and grind food into smaller pieces. The tongue helps push food to the back of the mouth where it is swallowed.

What type of digestion is this?

SALIVARY GLANDSSaliva is released to soften and help break apart the food.Saliva contains enzymes which break down the food into a useable form.

Did you know?• If saliva cannot dissolve something, you

cannot taste it. – In order for foods, or anything else, to have a taste, chemicals

from the substance must be dissolved by saliva. If you don’t believe it, try drying off your tongue before tasting something.

• On average, you produce 1.8 quarts of saliva each day.• During your lifetime, you will produce

enough saliva to fill two swimming pools.

2. After being swallowed, the food passes into the esophagus a muscular tube which connects the mouth to the stomach.

Peristalsis is the squeezing motion that pushes food down the digestive tract.

3. In the Stomach….• Chemical digestion- Gastric Juices like Hydrochloric acid

break food particles into smaller molecules• Mechanical digestion- the churning of the smooth muscles

physically breaks food into smaller pieces

Did you know?A meal may take up to three days to

pass through your digestive system. It spends about three hours in your stomach.

We eat about 1,100 pounds of food each year.

Did you know? The acid in your stomach is strong enough to dissolve

razorblades. Hydrochloric acid, the type found in your stomach, is not only good

at dissolving the pizza you had for dinner but can also eat through many types of metal.

….which is WHY…. You get a new stomach lining every three to four days.

The mucus-like cells lining the walls of the stomach would soon dissolve due to the strong digestive acids in your stomach if they weren’t constantly replaced. Those with ulcers know how painful it can be when stomach acid takes its toll on the lining of your stomach.

….what process does your body use to replace the cells lining the stomach….?

Helper Organs Gallbladder stores bile.

Liver produces bile and it is added in the small intestine to help break down food.

Pancreas – Create and release enzymatic

juices into the small intestine– Produces hormone insulin to

control blood sugar. Insulin is released into bloodstream.

4. The pyloric valve connects the stomach to the small intestine, which is a very long coiled tube-like organ.

VILLI are small finger-like projections that absorb the nutrients from the small intestine and carries them in the bloodstream to all the cells of the body.

Did you know?• The largest internal organ is the small

intestine. • Despite being called the smaller of the two

intestines, your small intestine is actually four times as long as the average adult is tall. • If it weren’t looped back and forth upon

itself it wouldn’t fit inside the abdominal cavity.

Large Intestine

Materials that are not digested move into the large intestine. Water is taken out of the remaining waste creating a solid called feces.Feces are stored in the rectum until it leaves the body through an opening called the anus.

Did you know?Every day 3 gallons of digested food, liquids and

digestive juices flow through the digestive system, but only 3 ounces are lost in feces.

A cow has three stomachs. It chews its food once and lets it digest partially in one stomach. Then it regurgitates the food up and chews it again continuing the cycle two or more times until its cud is fully digested.