5. BIOLOGY iX
Dear students,
Science is activity based. Its method is the unprejudiced investigation
of truth, based on scientific evidence. If what is generally considered
right today is scientifically proved wrong tomorrow, it would be
accepted. This is how science works. This rational method has to be
employed in learning science. Continuous observation,
experimentations and analyses lead the scientific perspectives to
new dimensions. Hence, you have to make use of every possible
opportunity to observe and experiment.
The student's role is pivotal in the process of construction of
knowledge. This science textbook is only a resource in the learning
process. Your teachers and supplementary materials will help you in
the creation of knowledge.
This book includes lessons which emphasis on Blood, its composition
and detailed information about blood cells and its functions.
The method of presentation is more conducive to the learner to
achieve knowledge and delight. We expect the textbook to be
helpful in the further learning of science.
Love and Regards,
Text Book Development Team.
6. BIOLOGY iX
TEXT BOOK DEVELOPMENT TEAM
Dr. saphia L.
(Assistant professor natural science department, CSI college of education)
Amritha Suresh B. S
(Teacher Trainee, CSI college of education parassala)
Ancy Mol M. A
(Teacher Trainee, CSI college of education parassala)
Adithya G.L
(Teacher Trainee, CSI college of education parassala)
Saja S.J
(Teacher Trainee, CSI college of education parassala)
10. BIOLOGY iX
1. TRANSPORTATION
Is sine’s doubt is genuine? Don’t you have doubts like these? What reply can
you give?
Is there any special transporting agent in our body to conduct nutrients? The
nutrients from the food get absorbed by the blood vessels and lacteal in the
villi of intestine. Isn’t it ?
Thus the nutrients are absorbed mainly through blood.
Almost all the nutrients
essential for our body are
from the food we eat. If so,
how these nutrients reach all
parts of the body??
What is blood ?
Blood is the fluid connective tissue , it circulate
throughout our body delivering nutrients and
oxygen to various cells and tissues . It makes
8% of our body weight. An average adult
possess around 5-6 litres of blood
11. BIOLOGY iX
1.2 Components of Blood
To know this, we must understand the components of blood.
Let’s familiarise with an experiment to understand this.
Experiment
Figure 1.1
If you add chemicals like EDTA (Ethylene Diamine Acetic acid) which is an
anticoagulant of blood, to a test tube containing blood, and wait for some
time. we can observe blood cells and the liquid part of ofthe blood distinctly as
showthe blood distinctly as shown in figure 1.1
Is the structure of blood
suitable to carry nutrients
and other substances?
12. BIOLOGY iX
From this experiment list down the various components of blood.
•
•
• Platelets
1.3 plasma
Did you notice Manu’s doubt? Have you had such doubts? What is that pale
yellow fluid from the wound?
Plasma is the pale yellow coloured fluid that constitute 55% of blood. Blood
cells are found in plasma. The simpler molecules formed as a result of
digestion namely, glucose, amino acid, fatty acid, glycerol etc. reach the cells
through plasma. Plasma plays a major role in the transport of simple nutrients.
With the help of indicators, analyse illustration 1.3.1
what is this white fluid
oozes out from my wound
….is it white blood??
13. BIOLOGY iX
Illustration 1.31
Indicators
• Factors absorbed through plasma
• Plasma proteins and their functions.
• The percentage of water
Do you know
Is blood plasma and blood serum is same?
No, Blood plasma is without plasma protein ‘Fibrinogen’.
14. BIOLOGY iX
1.4 BLOOD CELLS
These are cellular elements which are distinctly shaped and visible under
magnification. Blood consist of 45 % of blood cells. A blood cell also called
haemocyte or haematocyte, is a cell produced through haematopoiesis. Blood
cells include Erythrocytes (RBC), Leucocytes (WBC),and Thrombocytes
(Platelets).
Is the doubt of Ram is genuine? Have you had such doubts? What reply can
you give?
Why this insect has no
blood???
Why insects blood is white?
Insects have blood too.. but it is not
red, it is colourless due to the
absence of haemoglobin. Thus it is
called haemolymph.
15. BIOLOGY iX
• RBC (Red Blood Corpuscles)
Indicators
• Colour of RBC
• Shape of RBC
• Expansion of RBC
• Function of RBC
• Why the RBC appears in red colour?
• RBC Oxygen carrier
Technical term Erythrocytes
Shape Biconcave disc like structure flat in
the centre, thick and round in the
periphery.
Size 7 micron in diameter
Number 5 million
Life span 120 days
16. BIOLOGY iX
Formation and Disintegration of RBC
Stage Site of formation
Embryo Liver, Spleen
Children up to 5 year Red bone marrow of all bones
Adult Red bone marrow of long bones
About 2 million RBC’s disintegrates every second.In infantsSpleen and Liver are
the site of disintegration, but in adults it is in spleen only.
Abnormal conditions
Polycythaemia :Abnormal increase in the number of RBC.
Erythropenia :Abnormal decrease in the number of RBC
Formation of mature RBC
Illustration 1.41
RBC’s in embryonal stage have nucleus, mitochondria, Endoplasmic
reticulum. Once they are mature they lack these cell organelles.
Do you know
Mammalian RBC when
mature circulate in blood
system and devoid of
nucleus, mitochondria and
endoplasmic reticulum
17. BIOLOGY iX
Reason
Loss of nucleus: This results in the biconcave structure of RBC, in order
to increasethe surface area for maximum absorption of O2.
Lack of mitochondria :Cellular respiration occurs in mitochondria. Since
RBC’s are devoid of mitochondria. All the O2 absorb from the lungs are
delivered to the body tissues without self consumption.
Lack of Endoplasmic reticulum: This provide more flexibility to RBC ‘s , it
help them to move through narrow capillaries.
Haemoglobin
The colourless spongy body(stroma) of RBC contain the effective
respiratory pigment called Haemoglobin.
Haemoglobin
HaeminGlobin
‘Haemin’ is theIron part which is retained in liver and ‘Globin’is the
Protein part excreted as bilirubin (bile pigment).
o Haemoglobin combine with O2 to form oxyhaemoglobin (unstable
compound)
2Hb + O2 Hb.O2
o Haemoglobin combines with CO2 to form carbaminohaemoglobin
(unstable compound)
Hb + CO2 Hb. CO2
18. BIOLOGY iX
o Haemoglobin combines with CO to form carboxyhaemoglobin (stable
compound)
Hb + CO Hb.CO
• WBC ( White Blood Corpuscles)
Illustration 1.42
Indicators
• Function of WBC
• Types of WBC
WBCs are of two types Granulocytes and Agranulocytes. The
granulocytes are Neutrophils, Eosinophils and Basophils. Lymphocyte
and Monocyte are agranulocytes.
WBC Soldiers of body
• Technical term Leucocytes
• Shape Amoeboid shape
• Types Granulated, Agranulated
• Number 4500-11000 per cc of blood
• Life span 2 weeks
19. BIOLOGY iX
Is WBC has any role in our immune system?Yes, they protect us from
illness and other diseases. In sense they are always at a war. They flow
through the blood stream to fight virus, bacteria and other foreign
invaders that threaten our body.
With the help of indicators analyse the illustration 1.52 and complete
the given table.
Granulocytes Agranulocytes
• Neutrophils • Monocyte
• •
•
Formation and Disintegrationof WBC
WBC’s are produced in red bone marrow, lymph nodes, liver, it is about 125
billion neutrophils are produced each day. These are disintegrated inSpleen.
Abnormal condition
Leukaemia : Also known as blood cancer, is caused due to the abnormally
increased the number of WBC. Currently the treatment is blood transfusion.
Leukopenia : Abnormal decrease in the number of WBC.
Functions of WBC
1. Diapedesis
WBC can produce pseudopodia with which they can squeeze out through
the walls of capillaries in to tissues to engulf germs.
20. BIOLOGY iX
2.Phagocytosis
This is the process in which neutrophils engulf particle like solid
substances especially bacteria to avoid diseases. An abnormal increase
in WBC count up to50000 or more per cc of blood indicate some
infection.
2. Inflammation
This occurs due to reaction of tissues to injury and invasion of germs. The
inflamed spot usually show increased local heat , redness, swelling and pain.
The monocyte and neutrophils are responsible for this process.
21. 4.Formation of antibodies
neutralise the germs .Introducing weekend germs or vaccines during
vaccination stimulate the production of antibody against associated disease.
• PLATELETS
Did you notice the doubt of
bleeding does not ends up after a bleeding ?
helps in wound healing?
: The lymphocytes produced antibodies
ntroducing weekend germs or vaccines during
vaccination stimulate the production of antibody against associated disease.
Did you notice the doubt of Ammu? Have you had such doubt? Why the
bleeding does not ends up after a bleeding ? which are the substances
helps in wound healing?
Why don’t the bleeding ends
up ????????
BIOLOGY iX
he lymphocytes produced antibodies and kill or
ntroducing weekend germs or vaccines during
vaccination stimulate the production of antibody against associated disease.
you had such doubt? Why the
which are the substances
Why don’t the bleeding ends
22. BIOLOGY iX
Indicators
• Significance of platelets in wound healing.
• What happens when the platelets count become lower than
normal?
Platelets are tiny cells found in the blood and spleen. They help to form
blood clots for wound healing.Is there any problem due to the alter of
platelet count? Yes, if the platelet count is low which results excess
bleeding. If it is high causes blood clot in blood vessels. Thus the quantity
of platelets are significant in blood clot formation and wound healing.
Platelets Blood clotting
Technical term Thrombocytes
Shape Minute oval or round
Number 2-4 lakhs per cc of blood
Life span 3-5 days
PLATELETS COUNT
The general range of adult platelet has
been 150000-450000 platelets per micro
litre of blood.
23. BIOLOGY iX
Formationand Disintegration:
Platelets are derived from giant cells called megakaryocytes in red bone
marrow.It is also disintegrated in spleen.
Function of platelets
Illustration 1.43
Observe the illustration and find out how blood clotting occurs.
Steps of Blood clotting :
When a vessel is cut, blood escapes from it,clotting occurs in a series of steps.
Theinjured tissues cells and the platelets which disintegrate at the site of
the wound release a substance ‘thrombokinase’.
The thrombokinase act as an enzyme and with the help of the calcium
ions present in the plasma, it converts a substance ‘prothrombin’ of the
plasma , in to ‘thrombin’. Vitamin k, a fat soluble vitamin is essential for
the production of prothrombin.
24. BIOLOGY iX
Thrombin in the presence of calcium ions, reach with soluble
fibrinogenof the plasma to convert it in to insoluble fibrin. Fibrin is a
solid substance that forms threads. These microscopic threads of fibrin
are stick and form a network at the wound.
Blood cells are trapped in the network of the fibrin; the network then
shrinks and squeeze out of the rest of the plasma which is in the form of
clear liquid, the serum. The solid mesh which is left behind is called clot
or thrombosis
Abnormal condition
Haemophilia
Genetic disorder in which blood does not clot properly due to the lack of blood
clotting protein. Also in cases where the number of platelets falls in to
abnormally low count, coagulation occurs very slowly and often leads to
haemorrhage. Such a situation occurs in certain diseases as in the viral dengue
fever which has taken hundreds of lives in Delhi and other states of India since
1996 till date.
26. Let us Assess
1. Choose the simple nutrients which are absorbed in to blood from those
given below.
a) Fatty acid
b) Amino acid
c) Fructose
d) Glycerol
e) Glucose
2.Match the following
Plasma proteins
Albumin
Globulin
Fibrinogen
Extended activity
1. Conduct an experiment to understand the components of blood.
2. Prepare a science edition by including the information of various
blood cells.
Let us Assess
Choose the simple nutrients which are absorbed in to blood from those
function
Coagulation of blood
Regulate blood pressure
Helps in defence
Extended activity
Conduct an experiment to understand the components of blood.
Prepare a science edition by including the information of various
BIOLOGY iX
Choose the simple nutrients which are absorbed in to blood from those
Regulate blood pressure
Conduct an experiment to understand the components of blood.
Prepare a science edition by including the information of various
