Download The Excretory System

The H o m s n Body
Name
The Excretory System
The job of the excretory system is to take waste
out of the body. Another name for this system
could be the body waste system. The kidneys
form the most important part of the excretory
system. Other organs that remove wastes are the
lungs, the skin, the liver, and the large intestine.
What are the main organs of the excretory system
like? The kidneys are two, reddish-brown organs
about four inches long. They are in the lower
back. One is on each side of the backbone. The
kidneys are made of millions of tiny tubes and
cells. These tubes pull liquid waste from the
blood. This liquid is called urine. Urine is stored
in the bladder until it is passed from the body.
Other organs help the body get rid of wastes. As you breathe, the lungs remove carbon
dioxide from the blood. The liver takes out tiny bits of waste floating in the blood. The large
intestine, a part of the digestive system, takes in water and waste from food that is not
digested. The water is removed and the waste is passed out of the body.
The skin gives off waste by sweating. When you sweat, water and some salts pass through
tiny openings in the skin. These openings are called pores.
1.
What is the job of the excretory system?
2.
Name five organs of the excretory system.
3.
Tell how the kidneys help get rid of waste.
4.
How does the skin give off waste?
.« 1987 R E M E O I A P U B L I C A T I O N S
19
T H E HUMAN BODY 3
H i e If lasiassi B©siy
Name
T h e Excretory System
The Facts
G E T T I N G RID O F W A S T E :
1.
The job of the excretory system is to take waste out of the body.
2.
The kidneys are the most important part of the excretory system.
3l
Other organs that get rid of wastes are the liver, skin, lungs, and large intestine.
KIDNEYS:
1.
The kidneys are two reddish-brown organs about four inches long.
2.
The kidneys are in the lower back on each side of the backbone.
3.
The kidneys are made of millions of tiny tubes and cells.
4.
These tubes pull liquid waste from the blood.
5.
The liquid waste is called urine.
6.
Urine is stored in the bladder until it is passed from the body.
L U N G S , L I V E R , AND I N T E S T I N E S
1.
Lungs remove carbon dioxide from the blood when you breathe out.
2.
The liver takes out waste that is floating in the blood.
3.
The muscles of the large intestine push waste food out of the body.
SKIN:
1.
The skin is the largest excretory organ.
2.
The skin gives off waste by sweating.
3.
Sweat is made of water and salt.
4.
Sweat passes through tiny holes in the skin.
5.
Tiny holes in the skin are called pores.
• 1937 REMEDIA P U B L I C A T I O N S
22
T H E HUMAN B O D Y 3
Excretory System
i Understanding the Human Body
Name:
Date:
:
The Excretory System
^—•—•
:
; ~ ~
—
"
f a r Out F a c t ; Your kidneys filter your blood as many a s 400 times per day!
-\
Webwise: http://www.kidshealth.org/kid/htbw/kidneys.html
The job of the excretory system is to rid the body of wastes.
Solid wastes are removed from the body as part of the digestive system. When the nutrients
have been removed from the food you eat, the remaining material moves into the large intestine.
There, excess water is removed and what is left is stored in the rectum until it is full. Then it is
expelled through the anus.
Gaseous wastes are removed from the body as part ofthe respiratory
system. Waste gases from the blood travel to the lungs and diffuse into
the alveoli in the lungs. They are then expelled when you exhale.
Liquid wastes are removed from the body as part of the urinary
system and by the skin. These are what you will learn about in this
section.
Put each of these words under the correct heading to indicate if they are related to the
urinary tract or related to the skin.
ureter
dermis
epidermis
bladder
sweat glands
kidneys
urethra
pores
lJ
Urinary Tract
CD-404105 © Mark Twain Media, Inc., Publishers
Skin
53
Excretory System
Understanding the Human Body
The Urinary Tract
Far Out Fact: Your urine is yellow because of the bile in it.
Webwise: http://yucky.discovery.com/noflash/body/pg000128.html
The urinary tract consists of four principal parts. Study the material on this page and on
page 55 to learn about the urinary system. Then use the information to complete the activity on
page 56.
Kidneys: There is one on
each side of your body.
All of your blood passes
through your kidneys
hundreds of times a
day, and the wastes are
removed by tiny filters
called nephrons. Purified
blood is returned to your
circulatory system, and
the waste liquid (urine)
that is left behind flows
into collecting tubules in
each kidney.
Ureters: The urine
collected in the
kidneys drips into the
ureters, which are
tubes, connecting to
the bladder.
Bladder: This is an
elastic storage sac
that holds the urine
from the kidneys.
It can stretch to hold
about a pint of urine,
but when it is about
half full, it will send a
signal to your brain
that you need to go.
Urethra: When
you urinate, the
urine travels from
your bladder
through this tube
and out of your
body.
jlllr
CD-404105 © Mark Twain Media, Inc., Publishers
54
Excretory System
ynderstanding the Human Body
A Closer Look at Your Kidneys
Far Out Fact: An average adult will produce approximately one liter of urine each day.
Normally you have two kidneys, one on each side of your body.
• If you put your hands on your hips and slide them up until you feel your ribs, your kidneys
are about where your thumbs lie.
• They are shaped like kidney beans and are approximately 5 inches (13 cm) long and 3
inches (8 cm) thick.
• They are surrounded by fat for protection and to keep them in place.
• Blood enters the kidneys by way of a large renal artery and exits through a large renal
vein.
• Inside each kidney are around a million nephrons (tiny filtering units).
A Closer Look at a Nephron
• Nephrons consist of a bowl-shaped structure and a tubule that serves as a collecting
duct.
• Inside the bowl-shaped structure are capillaries (tiny blood vessels).They carry blood that
needs,filtering from the arteries.
• Water, salts, sugar, and wastes from your blood pass into the bowl-shaped structure.
• Liquid is squeezed into the tubules, where capillaries surrounding them reabsorb needed
water, salts, and sugar and send them back in the purified blood. Unneeded materials
and waste flow into the collecting tubules to make their way to the bladder and out of your
body.
CD-404105©MarkTwain Media, Inc., Publishers
55
Understanding the Human Body
Name:
Excretory,System
Date:
:
:
Urinary System True or False
yFar
Out Fact: You can survive with only one kidney.
Write "T" for true or " F for false.
1. Your liver is part of the urinary system.
2. All of the blood in your body passes through your kidneys once a day.
3. The main job of the kidneys is to filter your blood.
4. Waste liquid is called urine.
5. Urine travels from your kidneys to your bladder in the urethra.
6. Your bladder stretches to hold the urine until you pee.
7. Urine travels out of your body through the urethra.
8. Fat around the kidneys helps protect them.
9. Filtered blood leaves your kidneys through a renal artery.
10. There are 100 nephrons in each kidney.
11. Capillaries carry blood into the nephrons.
. — 12. Water, salts, and sugars pass into bowl-shaped structures in the nephrons. ,
13. Unneeded materials and waste travel to a collecting tubule, which is part of the
nephron.
14. Capillaries reabsorb needed water, salts, and sugars from the nephron.
_
15. Blood leaves the kidneys through a renal vein and returns to the main circulatory
system.
CD-404105 © Mark Twain Media, Inc., Publishers
56
Tlie H n m i
Name
Body
Tlie Excretory System
kidney
bladder
liver
skin
pores
system
urine
lungs
food
kidneys
blood
large
salt
is to take waste out of the
The job of the excretory
are the most important part of the
body. The
excretory system. The kidneys are made of millions of tiny tubes and cells. These tubes pull
liquid waste from the
i
:
- This waste is called
Urine is stored in the
Other organs help get rid of wastes. The
remove
takes out tiny bits of waste
carbon dioxide. The
floating in the bjood. The
intestine takes in water
and waste from
that is not digested.
The
gives off waste by sweating. When you sweat,
10
water and
pass through holes in the skin called
11
12
FILL IN T H E MISSING L E T T E R S . In the words below, some vowels are left out. Finish the
words. Remember the vowels are a, e, /, o, u.
1.
I_
2.
p.
3
bl
;
4.
k.
_r
s
d
. dn
9.
sw
rin
10.
bl
dd
.
11.
sk
n
5.
ngs
ys
« 1987 REMEOIA P U B L I C A T I O N S
nt.
6.
7.
f
8.
I
st
n
12.
v.
20
t
rg,
ns
THE HUMAN BODY 3
Name
T h e H u m a n Body
The Excretory System
DIRECTIONS:
DIRECTIONS:
Draw lines to tell what waste each organ helps the body get rid of:
1.
skin
undigested food
2.
kidney
carbon dioxide
3.
large intestine
water and salts
4.
lungs
i
urine
Write the correct letter on each line.
1.
bladder
A.
tiny holes in the skin
2-
liver
B.
an organ that stores urine
3-
pores
C.
main part of excretory system
4
-
kidneys
D.
takes out waste floating in the blood
5
-
large intestine
E.
part of the digestive system
urine
F.
6-
(
liquid waste stored in bladder