UNIT 2

LESSON 3

& 4

OP A

- C

HI N

O

THE

DIGESTI

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SYSTE

M/ THE

EXCRETO

RY SYS

TEM

B IG I

DEA

YOU M

AY N

OW S

PLIT

AND

EAT

YOUR C

OOKIE A

ND

PLEASE G

ET R

ID O

F TH

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NAPKIN

.

CALIFORNIA STANDARD

Science Standard 2.c:Students know the sequential steps of digestion and the roles of teeth and the mouth, esophagus, stomach, small intestine, large intestine, and colon in the function of the digestive system.

CALIFORNIA STANDARD

Science Standard 2.d:

Students know the role of the kidney in removing cellular waste from the blood and converting it to urine, which is stored in the bladder.

INPUT

• Digestive System – A group of organs and tissues that break food down into nutrients the body can use.

INPUT

• Excretory System – The organ system that removes wastes from the body.

• Kidney – The main organ of the excretory system.

• Transpiration – The process by which water moves out of plants through tiny holes in the leaves.

INPUT

• Food Breaks Down (Pg. 172)• The organs of the digestive system include

the mouth, esophagus, stomach, small intestine, and large intestine.

• It breaks food down into nutrients for the body.

• The nutrients move into the blood and are transported to the body.

• Digestion starts in the mouth with saliva

INPUT

• The stomach churns the food almost into a liquid.

• The food then moves to the intestine.• A long tube of muscle

INPUT

• Water and Nutrients are Absorbed (Pg. 174)

• There are 2 intestines• First is small intestine

• Connected to the stomach at one end• Chemicals from liver and pancreas are

added• Contractions break food down further• Lined with bumps called villi

• Villi increases surface area for nutrients to be passed to the blood.Villi are filled with

capillaries

INPUT

• Anything that cannot be broken down moves to the large intestine.• Peristalsis - wavelike movements that

move things through intestines (like food moving down esophagus).

• Solid waste collects and is expelled from the body.

INPUT

• The Excretory System (Pg. 182)

• CO2 is exhaled, but some waste cannot be exhaled.

• Ammonia is removed by the excretory system.• It is carried to the liver and converted to

urea then removed from the body.• Made up of the kidneys, ureters, bladder, and

urethra.• Kidneys remove cell waste from the blood• Ureters carry cell waste to the bladder• Bladder holds waste until it is released from

the body

INPUT

• How Plants Rid Themselves of Wastes (Pg. 184)

• Plants also have structures that remove wastes

• Plants do not have an excretory system• Some store waste in leaves that fall off each

year.

INPUT

• Some store waste in a large vacuole in cells

• Instead of kidneys, plants have stomata (tiny holes)

• Water moving out of the cells through tiny holes is called transpiration.

SUMMARY

Write your own!

You can do it!

UNANSWERED QUESTIONS

• Why is swallowing able to be controlled and peristalsis not able to be controlled if they are the same motion?

• Write your own…

ACROSS DISCIPLINES

Compare the sizes of different small intestines across the animal kingdom from the chart on page 175. Explain the significance of this chart, what it shows, and why.

MODELING

The digestion process begins with what part of the body?

Which organ removes cell waste from the blood?

CHECK FOR UNDERSTANDING

Which system do animals have but plants do not?

- The Excretory System

CHECK FOR UNDERSTANDING

Which organ comes after the stomach in the digestive system?

- The Small Intestine