Transcript Respiration - Physicslocker Index

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Releasing energy
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How is digested food used by the body?
The body needs a constant supply of energy which comes
from digested food.
Glucose, from digested carbohydrates, is an important
substance that contains stored chemical energy.
When glucose reacts with oxygen, a lot of energy is
released.
In the body’s cells, glucose and oxygen react to release
energy. Some of this is released as heat and the rest is
used by the cells.
What is the release of energy from glucose called?
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What is respiration?
Respiration is the process that the body uses to release
energy from digested food (glucose):
glucose
from the
digestive
system
+
oxygen 
from the
respiratory
system
carbon
dioxide
waste
product
(exhaled)
+
water ( + energy)
waste
product
(exhaled)
This type of respiration is called aerobic respiration because
energy is released in the presence of oxygen.
How do the glucose and oxygen needed for aerobic
respiration get to the all the body’s cells?
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Testing for the products of respiration
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How do cells get oxygen and glucose?
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The equation for aerobic respiration
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Respiration and combustion
Burning is the reaction between a fuel and oxygen. This
reaction is called combustion:
fuel
+
oxygen

carbon dioxide
+
water
During combustion, heat and light energy are released and
carbon dioxide and water are also produced, so
combustion is similar to respiration.
The difference between combustion and respiration is that
combustion is not a controlled reaction. Respiration is a
controlled reaction that slowly releases energy from food in
the body’s cells and the cells do not catch fire!
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Respiration and combustion
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The circulatory system
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Circulation
The dissolved food and
oxygen needed for respiration
are carried around the body
by the circulatory system.
The circulatory system
includes the blood, blood
vessels, the heart and
the lungs.
Which part of the
circulatory system actually
carries dissolved food and
oxygen to the body’s cells?
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Blood
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Your beating heart
The heart is made of very special
muscle called cardiac muscle.
This is because it has to keep beating
for the whole of a person’s life!
If you tried to do the same action
repeatedly (like the heart does),
your muscles would get tired
and, after a while, stop working.
For example, if you keep clenching and unclenching your
hand, it will get tired and may even start to get cramp.
Why is it important for respiration that the heart keeps
beating?
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Ideas about circulation
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Measuring pulse
The heart pumps blood around the body in the blood vessels.
Each time it pumps it causes the blood vessels to throb.
This is called a pulse.
To take your pulse:
1. Hold out one hand with the palm facing up.
2. Put the index and middle fingers
of your other hand together.
3. Press these fingers
lightly on the underside
of the other wrist, just
under the thumb bone.
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Different types of activity
What happens to the pulse while someone is running?
During exercise, the pulse rises. This causes
blood to be pumped around the body more
quickly, which increases the amount of oxygen
and glucose that can reach muscle cells.
What happens to the pulse
while someone is sleeping?
During sleep, the pulse falls. This causes
blood to be pumped around the body
more slowly. This means that oxygen and
glucose take longer to reach muscle cells.
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The breathing system
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What is breathing?
The breathing system is used by the body
to get the oxygen needed for respiration.
It is also used to get rid of one of
the waste products of respiration:
the gas, carbon dioxide.
Breathing in and breathing out are
separate processes in the body.
Breathing in is called inhalation. When you inhale, you
breathe air, including oxygen, into your lungs.
Breathing out is called exhalation. When you exhale you
breathe out the contents of your lungs and get rid of the
waste gas carbon dioxide.
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Inhalation and exhalation
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The alveoli
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Gas exchange
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Comparing inhaled and exhaled air
What are the differences between inhaled and exhaled air?
Exhaled Air
Inhaled Air
Oxygen:
21%
Oxygen:
16%
Carbon dioxide: 0.04%
Carbon dioxide:
Water vapour:
small amount
Water vapour:
large amount
4%
What are the main differences?
How could you test for the differences between inhaled
and exhaled air?
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Respiration
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Anaerobic respiration
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Aerobic and anaerobic respiration
When the body is able to supply its cells with the oxygen
and glucose that they need, it carries out aerobic
respiration.
glucose
+ oxygen 
carbon
dioxide
+ water ( + energy)
When the body cannot supply the cells with the oxygen
needed to break down glucose, then it has to carry out
anaerobic respiration. Energy is released without oxygen:
glucose  lactic acid
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energy
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Not enough oxygen!
glucose

lactic acid
+
energy
When anaerobic respiration takes place, lactic acid
is also produced.
Lactic acid builds up in the muscle
cells and prevents the muscles
doing their job. This is thought to
cause fatigue and sometimes cramp.
After exercise the body needs to
remove the lactic acid before it
causes damage to cells.
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Oxygen debt
Lactic acid is broken down by oxygen.
lactic acid
+
oxygen  carbon dioxide
+
water
After activity that has lead to
anaerobic respiration, the person
involved breathes heavily and their
heart rate remains high to supply
the body with the oxygen it needs.
The amount of oxygen needed to
remove all the lactic acid after
exercise is called an oxygen debt.
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How does running affect your pulse?
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Anaerobic respiration equations
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Summary activities
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Glossary
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Anagrams
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Multiple-choice quiz
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