Cells get nutrients through the digestive and circulatory systems. The digestive system breaks down food into simple substances that can be absorbed and transported by the bloodstream to cells throughout the body. Food is broken down mechanically and chemically as it passes through the mouth, esophagus, stomach, small intestine, large intestine, and colon. Nutrients are absorbed into blood vessels in the small intestine and transported to cells. Cells produce waste which is collected by the blood and filtered by the kidneys. The kidneys convert waste into urine which is stored in the bladder.

1. Living Systems
Focus Question: How do cells get
the food they need?
Investigation 1-2

2. Investigation Review
Life happens in cells
Multicellular organisms are made of many
living cells
Cell need certain resources to survive,
including
Water
Food
Gas Exchange
Waste Removal
Circulatory system circulates blood, which
transports the substances living cells need

3. The first part of this investigation
focused on the circulatory system’s
relationship with the respiratory system.
The result was gas exchange.
We found out how cells get the oxygen
they need and get rid of the waste gas,
carbon dioxide.
In this part of the investigation we will
find out how cells get the food they
need and how they get rid of wastes
that are not gases.

4. Focus Question:
Talk in your groups about how you
think cells get the food they need and
what kind of food cells use.
Ideas?

5. Cookie Challenge
Imagine that you are small enough to fit
on the cookie before you.
As you eat the cookie, draw the route
you are taking on the human body
outline. Then, write what is happening
at each stage of the route.

6. Digestion
When you eat a cookie, soup and
sandwich, or a burrito, you are
providing food for your cells.
Cells can’t eat bread, lettuce, mustard,
and cheese.
Cells can only use simple substances
for food.
Food you eat has to be changed into
food that cells can use.
Process is called digestion.

7. Digestion is a long process.
Like a disassembly line.
Complex food goes in at one end of the
line.
It is taken apart bit by bit as it moves
through the system.
Read an article about the digestion
process to find out how food we eat is
turned into food that our cells can use.
Pg. 91-94, Disassembly Line
Answer notebook questions when done

8. The Disassembly Line Review
Why do people eat food?
What happens to food in the digestive
system?
Describe the path taken by food as it
passes through the digestive system.
Explain what happens to food at each
place in the digestive system.
How does digested food get to cells?
Why do people need kidneys?
Describe how kidneys work.

9. Digestion Video
Watch and listen for information that
confirms or extends what you know
about the digestive system
Think about how new information
relates to the big idea of life support for
cells
Review Video Questions

10. Experiment Review
The students in the video conducted an
experiment to find out what happens to
food (hard-boiled egg white) in different
environments.
Talk in your groups about the
experiment:
What was the question?
What was controlled?
What was changed?
What were the results?
What was the conclusion?

11. System Interaction
How do the digestive and excretory systems
interact?
Digestive system breaks the food into
molecules that the blood transports to all the
cells in the body.
Cells produce waste, which enters the blood.
Waste travels to the kidneys, which filter it out.
Two systems interact where the cell
exchanges food and waste with the blood
The end of the large intestive (at the colon)
recycles water, compacts remaining solids
and send to rectum, to be eliminated through

12. Digestive system -
Disassembles food into nutrients that cells can
use
Mouth and Teeth -
Moisten and crush food before it moves through
the esophagus to the stomach
Esophagus -
Tube connecting the mouth and stomach
Pushes food through by peristalsis - squeezing
Digestive juices -
Juices added to food in the stomach, small
intestine, and large intestine to help release
nutrients into the bloodstream.

13. Stomach -
The organ where food is reduced to mush
by acid and muscle activity (squeezing).
Small Intestine -
Where digestion really happens.
Nutrients from digested food are
absorbed into the bloodstream.
Large Intestine -
Water is removed from undigested food,
leaving solid waste.

14. Colon -
End of the large intestine where food waste
is compacted and dehydrated
Kidney -
Filters cellular waste from the blood and
turns it into urine
Urine -
Liquid waste produced by kidneys
Bladder -
Organ that stores urine until it is eliminated

15. How do cells in humans get the nutrients
they need?
The digestion system reduces food to
nutrients. Nutrients pass out of the digestive
system into the bloodstream for transport to
all the cells.
How does the digestive system work?
Physical and chemical processes break
complex food into simple substances as it
progresses from the mouth through the
esophagus to the stomach, small intestine,
large intestine, and colon.

16. How are cellular wastes removed from
the blood?
Blood filters through the kidneys, which
remove cellular wastes, convert them
into urine and store them in the
bladder.
Your questions?
Homework: Read Summary: Living
Cells, page 95-98 & answer questions
I-check 1 on Friday, 9/27, notebooks
due for grading at that time.