Download Respiration, Circulation and Excretion

3
Respiration, Circulation
and Excretion
L O O K A N D C O M PA R E
1. Compare the picture and
photograph above. What are the
people doing? What differences
do you notice?
THINK AND EXPLAIN
● What does the astronaut need to
be able to breathe on the moon?
2. Describe the scuba diver’s
equipment. What are the fins
for? Why does he have tanks on
his back?
3. Which of the two divers will
be able to stay underwater
longer? Explain your answer.
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1. Respiration
Questions
1. What is respiration?
2. Which organs make up
the respiratory system?
3. How do we breathe?
It is impossible to breathe on the moon because
there is no air. Space suits have a special helmet
and air tanks that allow the astronauts to breathe.
The Respiratory System
People need to breathe. We use the organs of the
respiratory system to breathe.
nostrils
trachea
nose
• The nostrils are in the head. The nose links
the nostrils to the exterior of the body.
• The trachea is a tube inside the neck.
left lung
(internal view)
right lung
(external view)
• Each of the lungs is shaped like a bag. The
lungs are in the chest and are protected by
the rib cage.
The heart is between the lungs, a little closer to
the left lung. As a result, the left lung is a little
smaller than the right lung.
ribs
lungs
The Respiratory System
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How We Breathe
Your body makes two movements to breathe,
inhalation and exhalation.
• Inhalation occurs when air enters the lungs.
When you inhale, air enters through the nose
and mouth, travels down the trachea and fills
the lungs. The lungs expand and swell.
• Exhalation occurs when air exits the lungs. The
lungs contract and expel the air through the
nose and mouth.
Humans can breathe through their noses
and mouths. The air that you breathe through
your nose is cleaner, warmer and more humid
when it reaches your lungs than the air that you
breathe through your mouth. The nostrils have
little hairs that catch dust in the air you breathe.
The lungs fill with air when you inhale.
Activities
KEY WORDS
1
Complete the sentences with the key words.
inhalation
exhalation
• Air enters the lungs during
• Air exits the lungs during
2
.
.
Copy the picture of the respiratory system.
Label the parts.
EXPLAIN
3
Explain the following:
• The left lung is slightly smaller than
the right.
• The chest swells during inhalation.
4
The lungs expel air when you exhale.
Why is it better to breathe through the nose
than through the mouth?
Explore
Breathing Rate
• Do you breathe faster when you
are reading or when you are
running?
• Make a list of situations in which
you breathe very fast.
• Why do we sometimes breathe
very fast?
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2. Circulation
Questions
1. What is the purpose of blood
circulation?
2. Which organs make up the
circulatory system?
3. What does the heart do?
Heart
direction of
blood flow
The Whole
Body
Lungs
Heart
Diagram of Blood Circulation
Blood and Circulation
Our blood takes the substances we need to all parts
of the body so that they function properly.
Blood also collects waste products along the way.
The movement of blood through our bodies is
called circulation.
heart
The Circulatory System
The circulatory system is responsible for circulation.
This system is made up of the heart and blood
vessels.
Blood vessels are tubes that transport your blood
throughout your body. There are two types of
blood vessels: veins and arteries.
• Veins carry blood to the heart from the rest of
the body.
arteries
veins
• Arteries carry blood from the heart to the rest
of the body.
The heart is the organ that pumps blood
throughout the body. Every time the heart beats,
it pumps blood. Then the blood flows through
the arteries to the rest of the body. The heart
never gets tired. It beats more than 100,000
times a day.
Some Veins and Arteries in the
Human Body
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Explore
vein
artery
Your Pulse
You can take your pulse to find out
how fast your heart beats.
muscle
Look at the picture. To take your
pulse, place two fingers on the inside
of your wrist, under your thumb.
Each time the heart beats, you feel
a movement in these veins.
External View of the Heart
Take your pulse and observe.
• How many times a minute does
your heart beat?
Activities
KEY WORDS
1
Complete the sentences with the words in
the box.
heart
blood vessels
• The
• Run a little. Take your pulse
again. How many times does
your heart beat now?
• When does your heart beat faster?
blood
are tubes that
carry blood.
• The
takes oxygen and
nourishment to all parts of the body.
• The
pumps the blood.
EXPLAIN
2
Which sentences are true? Why?
• Blood circulation is continuous.
• Blood circulation stops when we sleep.
• Blood circulation stops when we eat.
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3. Excretion
Questions
1. What is excretion?
2. Which organs make up
the excretory system?
3. What is urine?
internal
view
of a kidney
4. What is sweat?
external
view of a
kidney
ureters carry urine
from the kidneys
to the bladder
blood
vessels
bladder
urine outlet
The Excretory System
How We Eliminate Waste Products
from Our Blood
kidney
kidney
The blood collects all the waste products in your
body. There are organs that constantly clean the
blood so waste products do not accumulate.
The elimination of waste is called excretion. The
excretory system and the skin are responsible
for excretion.
The Excretory System
bladder
The excretory system is in the abdominal area.
Some parts of it are behind the intestines and
other parts are below the intestines.
The kidneys are the most important organs
in this system. Their job is to clean the blood.
Urine is the liquid formed by the kidneys after
cleaning the blood.
Urine is stored in the bladder and then eliminated
from the body.
Location of the Excretory System
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FOTO
When we exercise, we sweat more.
When it is very hot, we sweat more.
Sweat Helps Purify the Blood
The skin is also very important for excretion. There
are glands beneath the skin that help clean the
blood. The waste products are eliminated as sweat.
Some parts of your body produce more sweat
than others. For example, your head and your
armpits sweat more than your back or your legs.
Explore
Perspiration
Activities
KEY WORDS
1
Make a sentence with each pair of words.
• excretory system, skin
• kidneys, blood
• urine, sweat
EXPLAIN
2
• Do all parts of the body produce
the same amount of sweat?
• Which of the following produces
the most sweat: the palms of the
hands, thighs, feet, head, armpits,
abdomen, ears?
• Do we perspire more when it is
very hot or when it is very cold?
Can sweat keep us cool when it
is hot?
Could we live without kidneys?
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HEALTH EDUCATION
Skin
The Parts of the Skin
hair
pores
Your entire body is covered by skin. All areas
of the human body have skin.
surface
layer
The skin has an internal layer, which you
cannot see. It also has a surface layer in
contact with the air. You shed this surface
skin constantly and new skin replaces it.
• There are various elements on the surface
of the skin, such as hair and pores. You
eliminate sweat through your pores.
• There are small blood vessels in the
internal layer of the skin. Sweat glands
and tactile nerves are also there. Sweat
glands produce sweat and tactile nerves
give you a sense of touch.
internal
layer
blood
vessels
sweat
gland
Internal and Surface Layers of the Skin
What Skin Does
The skin has several functions, all very
important. Some of these functions are:
• It protects us from the sun’s rays.
The skin filters sunlight and prevents
it from harming the body.
• It prevents us from losing water.
Thanks to the skin, the body does not
dry out.
• Our sense of touch is in the skin.
Because there are tactile nerves in the
skin, we can feel the things that are
around us. Our sense of touch tells us
if an object is rough or smooth, hot or
cold, sharp or blunt, etc.
• The skin plays a role in excretion by
producing sweat.
The sense of touch is well developed in babies.
They use their hands to explore objects and to
relate to adults.
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Discover
Skin Color
Skin Care
You should bathe regularly to keep your skin
healthy. A shower washes away sweat. If sweat
accumulates, it smells bad and can irritate your skin.
You should protect your skin with sunscreen
when you are in the sun. Sunscreen contains
substances that filter the sun’s rays. Your skin
may burn if you are in the sun for too long, or if
you do not use sunscreen.
If you get burned by the sun often over the years,
you can do serious damage to your skin.
The skin can be many different
shades and colors. It can be
pale, ruddy, brown, black, dark,
sallow, etc.
The reason for this wide variety of
color is very simple. There are dark
substances, or pigments, in the
superficial layer of the skin. If there
is a lot of pigment, the skin will
be dark. If there is only a little
pigment, the skin will be light.
1
2
3
4
Activities
1
Copy the picture of the skin in your notebook.
Label the parts.
2
Copy and complete the chart below.
The Skin
has
layer
where there are
layer
where there are
3
What sensations can we feel through our
skin? Make a list.
4
Imagine that you are blindfolded. What can
you tell about the following objects by
touching them?
• sponge
• rock
• string
• cellophane
• pencil
• shoe
• Look at the photographs. Describe
the children using a table. Write
these headings along the top of
the table: skin color, hair color
and eye color.
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Activities
REMEMBER
1
Label the drawings.
1
3
4
2
6
7
5
system
system
2 Explain the differences between:
• kidneys and bladder.
3
• nostrils and trachea.
• heart and blood vessels.
Complete the chart.
Blood Vessels
Types
Function
SYNTHESIZE
4
Which of these processes do we carry out continuously, even while we sleep?
• digestion
• respiration
• blood circulation
• excretion
APPLY
5
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What is a blood transfusion? Why is a blood transfusion sometimes necessary?