Human Digestion
Science 7
by:
Mr. Rockensies
Aim: How does the digestive system
break down food into nutrients?
Do Now: How many feet does your food
travel through the digestive system?
HW: Worksheet
The Stormy Sea
“Then, the valve to the stomach opens and
pizza mush lands in your stomach!”
“The small intestine looks like a strange underwater
world filled with things that resemble small finger-like
cactuses.”
“A glorious, if slightly stinky,
journey, don't you think?”
In-class Exercises
Name the term used to describe the muscular contraction that
pushes your food down the esophagus and into the stomach.
peristalsis
Describe the role that mucus plays in the
stomach.
Acts as a liner, protecting the stomach from acid burns
Determine the 5 steps that food takes as it travels through
the digestive system.
1) Eat the food
2) Food enters stomach and is further digested by acid
3) Nutrients are absorbed by the small intestine
4)Waste not absorbed has water taken out by large intestine
5) Waste is removed from the body
In-class Exercises
What is
The breakdown of food so that it can be
digestion? absorbed
EDDiE
E Eat/Ingest
You chew food with your teeth,
breaking it down into smaller
pieces. Saliva breaks down starch
molecules into simple sugars.
D Digestion
The esophagus pushes the food
down to the stomach using
peristalsis. The stomach fills with
acid and contracts to mix the food
and acid.
Di Diffusion
After the stomach, the food enters
the small intestine and is mixed with
juices filled with enzymes that
further break down food to be
absorbed by villi
E Eliminate/ Egest
Food then travels to the colon, or
large intestine, where it is
dehydrated. The water is removed
and the remaining waste is then
pushed out of the body by the
rectum through the anus
In-class Exercises
How is food
broken down?
a) physical
changes
Food is broken down
mechanically – chewing,
mixing, grinding
Ex: Teeth chewing, stomach
churning
b)chemical
changes
Food is mixed with acids and
digestive juices containing
enzymes to further break down
food and release nutrients for
absorption
In-class
Exercises
1) E - eat/ingest
Mouth, teeth, salivary glands, tongue, esophagus
2) D - digest
Stomach, pancreas, liver, gall bladder, small
intestine
3) Di - diffusion
Small intestine (villi), large intestine
4) E - eliminate/egest
Large intestine, rectum, anus
Hypothesize what might happen if H2O was not
removed during the final stages of digestion in the
large intestine.