© REGION 4 EDUCA TION SERVICE CENTER.
ALL RIGHTS RESERVED.
Dangerous metabolic by-products such as hydrogen peroxide are chemically
changed into less harmful substances by
enzymes.
Indigestible parts of chyme
are moved along to the large intestine, where usable water and minerals are
absorbed.
Unusable waste material is expelled from the anus.
cienc
e
Sheets • 200 Pages • Wide Ruled
9 3/4 x
7 1/2 in. • 24.7 x 19.0 cm
changes, chemical changes, or both physical and chemical changes
occur in each organ.
Organ
Physical,
Chemical,
or Physical and
Chemical Changes
mouth physical (chewing);
chemical (enzymes)
esophagus
physical (food is squeezed and changes
shape)
stomach
physical (mixing);
chemical (digestion by
HCl
and enzymes)
small intestine chemical (enzymes break down molecules)
large intestine physical (water is removed)
The Excretory System
The daily activities of cells include chemical reactions that require energy from
food.
Chemical waste products are formed as a result of these activities and are
moved out of the cells and into the blood.
In order to maintain a balance in the
body, the blood must be cleaned of these waste products. The kidneys are the
main organs of the excretory system.
Figure 5.2. The Excretory System
kidney
ureter
urinary bladder
urethra
Lesson 1: Physical and Chemical Changes in Digestion
Unit 5:
Structure and Function of Organisms, Part 2
