Download How does blood help to keep us alive

How does blood help to keep us alive?
Have you ever wondered what blood is made of, what red and white blood cells do or
how the respiratory system (lungs) is connected to the cardiovascular system (hearts and
blood)? Well this text will help you answer all these questions.
Blood is made up of trillions of cells that need oxygen to live. With out oxygen the cells
would die causing the person to die. Plasma makes up 55% of blood, red blood cells
make up 44% and white blood cells make up less than 1%. Plasma is a pale yellow liquid
which carries all the red and white blood cells, platelets and chemicals around the body.
Red and white blood cells will be explained later in the text. Platelets are sticky cells that
move around in your blood stream until a blood vessel is injured (when you cut yourself
and you start bleeding). Then the platelets join together with a protein called fibrinogen
to produce a sort of web to clot the blood vessel. This stops the bleeding which prevents
you from loosing blood.
Red blood cells are responsible for taking oxygen around the body and picking up carbon
dioxide and bringing it back to the lungs. Once the blood has gone through the lungs and
picked up the oxygen it circulates all around the body making sure that every spot in your
body has enough vitamins, nutrients, oxygen and blood to work properly. When red
blood cells go through the lungs they release an iron-containing substance called
haemoglobin that picks up the oxygen. White blood cells play the role of the defenders of
the body against germs, diseases and illnesses. Some white blood cells move around the
body in the blood stream until there is a germ in the body. Then they go to where the
germ is and destroy it before it can flow around the body. Other white blood cells
produce chemicals called antibodies which stick onto germs making them easier to
destroy or get rid of. White blood cells are round with tiny flakes on the surface to help
them stick to germs.
Have you ever wondered what happens when you breathe in? Well, when you breathe in
blood gets pumped out of your heart from the two lower chambers of the heart called
ventricles to your lungs where the blood picks up the oxygen that you breathed in. Then
the blood travels to all parts of your body through tubes called arteries. After it has gone
every where in the body it will return back to the lungs through veins so that the old
oxygen can be breathed out as carbon dioxide. Then the cycle starts all over again.
Red blood cells
with oxygen
(Oxygen is the
green circle and
red blood cells
are the red ovals)
Germs
Plasma
White blood cells
Platelets
surrounding the
injured blood
cell
The heart is one of the main organs in the cardiovascular system. The heart is a muscle
and is found to the left of your chest. It is made of a cardiac muscle (a special muscle that
contracts rhythmically of its own accord). In the heart there are four chambers. The upper
two chambers are called the left and right atrium. The two lower chambers are called the
left ventricle and the right ventricle. The two ventricles are the parts of the heart that
pumps the blood around the body. The atriums together are called atria. The atria are the
parts of the heart that fills up with the blood that has just come from the body and the
lungs. The ventricles pump out the blood that will eventually go to the lungs then
circulate around the body. The left and right sides of the heart are separated by a thick
wall of muscle called the septum.
Our heart beats around seventy times per minute when we are relaxed. But have you ever
wondered if our heart beat could change speed and beat faster or slower? Here is an
experiment that can help you determine how your heart beat changes from when you
haven’t done exercise to after you have done exercise.
You will need:
Stethoscope
Place to move around
Piece of paper
If you do not have a stethoscope you can feel your heart beat (pulse) in your wrist or
the side of your neck. If you are having trouble feeling your pulse in those places you
can put your hand on your heart and listen really carefully.
Steps:
1.
Check your pulse and count how many times your hear beats in ten seconds.
Then times it by six to get a minute. Then write your first score on a piece of
paper.
2.
Then do twenty star jumps.
3.
Then check your pulse and count how many times your heart beats in ten
seconds. Then times it by six to get to a minute. Then write your second score
on a piece of paper.
How was your first heart rate different from your second heart rate? It was different
because there are nerve signals that are sent from the brain that can speed up the brain
that can speed up our heart rate if we are doing exercise or if we are stressed. If you
want to see if you can get a bigger difference between your first and second score do
more than twenty star jumps or do another form of exercise.
With out blood our body would have lots of germs flowing around in our blood
stream and we would get lots of illnesses and diseases. Also our body wouldn’t get
the oxygen, nutrients or vitamins it needs. With out oxygen we can not live.
Bibliography:
Blood, E.Encyclopedia, Google, Dorling Kindersley Limited, Great Britain, 2006. pp
134-135 (18 April 2010)
Kids Health, Heart and Circulatory
System, 2010,
http://www.kidshealth.org/PageMa
nager.jsp? (21 April 2010
Kid Cyber, Heart and blood, 2004,
http://www.kidcyber.com.au/topics
/body/blood.html (21 April 2010)
Britannica, blood, 2010,
http://www.k8.eb.com.au/elementa
ry/aricle?articleId (22 April 2010)
The children’s Heart Institute,
Heart,
http://www.childrensheartinstitute.
org/ , date published unknown, (22
April 2010)
Kids Health, blood, 2008,
http://www.cyh.com/HealthTopics/HealthTopicsDetails.aspx?p (22 April 2010)
1055 words
Picture taken from Encyclopedia Britannica
©2008