Dept. of Science
Middle East School
Grade – 9 - Biology
Name: …………………………………… Class: ………..… Date: ………………….
Chapter 5 – Blood and Circulation. Key points
1) The circulatory system consists of the heart (the pump), the blood vessels (the
pipes) and the blood (the medium).
2) Functions of blood - Blood transports: a)oxygen from the lungs to the body cells. b)
carbon dioxide from the cells to the lungs. c) nutrients from the gut to all parts of the
body. d) urea from the liver to the kidneys. e) hormones and antibodies and
f)distributes heat around the body.
3) Single-celled organisms (e.g. – Amoeba, paramecium and euglena) do not have
circulatory systems. Materials can easily move around the cell without a special
system. Their cell surface membrane has a large area to supply all the oxygen they
need. (Because it has a large surface area compared with its volume.)
4) There are two main types of circulatory systems in animals – single circulatory
system and double circulatory system.
5) In single circulatory system - The blood passes through the heart once on one
complete circulation of the body and in double circulatory system the blood passes
through the heart twice on one complete circulation of the body.
6) Single circulatory system – The blood is pumped from the heart to the lungs (gas
exchange organ) and then directly to the rest of the body. e.g. – Fish.
7) In double circulatory system, the heart pumps the blood twice, so higher pressure
can be maintained and the blood travels more quickly to the organs.
8) Human circulation is called a double circulatory system – The heart pumps blood to
the lungs to pick up oxygen (pulmonary circulation). Oxygenated blood flows back to
the heart. Then it is pumped out to the rest of the body (systematic circulation). e.g.
– humans, mammals, birds.
9) The heart pumps blood around the body. It is made of a special type of muscle called
cardiac muscle. This muscle contracts and relaxes continuously without becoming
fatigued.
10)The heart is divided into four chambers. The two upper chambers are called atria
and the two lower chambers are called ventricles. The chambers on the left-hand
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Middle East School
Grade – 9 - Biology
Name: …………………………………… Class: ………..… Date: ………………….
Chapter 5 – Blood and Circulation. Key points
1) The circulatory system consists of the heart (the pump), the blood vessels (the
pipes) and the blood (the medium).
2) Functions of blood - Blood transports: a)oxygen from the lungs to the body cells. b)
carbon dioxide from the cells to the lungs. c) nutrients from the gut to all parts of the
body. d) urea from the liver to the kidneys. e) hormones and antibodies and
f)distributes heat around the body.
3) Single-celled organisms (e.g. – Amoeba, paramecium and euglena) do not have
circulatory systems. Materials can easily move around the cell without a special
system. Their cell surface membrane has a large area to supply all the oxygen they
need. (Because it has a large surface area compared with its volume.)
4) There are two main types of circulatory systems in animals – single circulatory
system and double circulatory system.
5) In single circulatory system - The blood passes through the heart once on one
complete circulation of the body and in double circulatory system the blood passes
through the heart twice on one complete circulation of the body.
6) Single circulatory system – The blood is pumped from the heart to the lungs (gas
exchange organ) and then directly to the rest of the body. e.g. – Fish.
7) In double circulatory system, the heart pumps the blood twice, so higher pressure
can be maintained and the blood travels more quickly to the organs.
8) Human circulation is called a double circulatory system – The heart pumps blood to
the lungs to pick up oxygen (pulmonary circulation). Oxygenated blood flows back to
the heart. Then it is pumped out to the rest of the body (systematic circulation). e.g.
– humans, mammals, birds.
9) The heart pumps blood around the body. It is made of a special type of muscle called
cardiac muscle. This muscle contracts and relaxes continuously without becoming
fatigued.
10)The heart is divided into four chambers. The two upper chambers are called atria
and the two lower chambers are called ventricles. The chambers on the left-hand
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