biology grade 10 icse

1. THE CIRCULATORY SYSTEM

2. NEED FOR TRANSPORT INSIDE THE BODY
1. Digested food is transported to the various
parts of the body through the blood.
2. Respiratory gases are carried to the tissues
by the blood
3. Excretory products are carried to the
excretory organs by the blood
4. Hormones are carried to their target organs
by the circulatory system

3. BODY FLUIDS
Humans have a closed vascular
system i.e. blood flows in vessels
and does not bathe the
tissue/organ directly. The three
circulating fluids in the human
body are blood, tissue fluid and
lymph. The body fluids are a means
of transport for the various
physiological activities.

5. FLUIDS IN OUR BODY-- PRINCIPLE FLUIDS ARE
Circulating Fluids –
Blood—found in the heart and blood vessels
Tissue fluid—found around the cells of the tissue
Lymph—found in lymph vessels which eventually
open into the circulatory system. They have nodes.
Non Circulating fluids –
Synovial fluid—found in the cavity of the skeletal
joints.
Aqueous humour—found in the eye in front of the
pupil.

7. THE BLOOD—CHARACTERISTICS
• Never stationary
• Red in colour—bright red in the artery
Dark red in the veins
• Each person contains 5—6 litres of blood in
their body
• It is slightly alkaline pH 7.3—7.45 (salty in
taste)

8. FUNCTIONS OF THE BLOOD
The two main functions of the blood are
transport and protection
• Transport of digested food and minerals from
the villi of the alimentary canal to the areas where it is
needed or storage organs.
• Transport of respiratory gases
O2 from the lungs to the tissues with the help of
RBC which contains haemoglobin
Hb + O2------------→Hb.O2
CO2 from the tissues to the lungs
Hb + CO2 -----------------à Hb.CO2

9. vTransport of excretory products from the cells to
the excretory organs from where they can be
eliminated.
Example liver, kidney and skin
vTransport of hormones from the site of their
production to site of action
vHelp in distribution of heat from the muscles to
different parts of the body thus maintaining the
body temp.
vThe formed element and proteins found in the
blood help in formation of clots when there is
injury
vWBC in the blood helps in fighting diseases by
engulfing bacteria or any other foreign body.
vWhite Blood cells produce antitoxins and
antibodies to kill germs and neutralize poison.

10. COMPOSITION OF BLOOD
The blood contains
i.Plasma—which is the fluid part
and
ii. Formed elements—
which are RBC, WBC and blood
platelets

12. PLASMA— contains
Water
Proteins
Inorganic salts—NaCl and sodium bi carbonate
Other substances-- glucose, amino acid,
hormones, urea etc.
Cellular elements are
RBC—red blood cells (erythrocytes)
WBC—white blood cells (leucocytes)
Blood platelets (thrombocytes)

14. BLOOD IN AN ARTERY

15. RBC

17. RED BLOOD CELL
THE OXYGEN GAS CARRIER
uMinute concave disc like
uFlat in the centre and thick at the
periphery—no nucleus
uVery small app. 7 microns in diameter
( 1 micron= ⅟1000 of a millimetre)
uTheir concave structure provide them
large surface area for transporting
oxygen
uThe small size enables them to move
through very fine capillaries
u The body of the RBC is colourless and
spongy called stroma

18. uIt contains a respiratory pigment called
Haemoglobin. Haemin—iron globin—
protein
uHaemoglobin has the ability to combine
with oxygen to form oxyhaemoglobin and
carry it to the cells
uHaemoglobin can only combine with a small
amount of carbon dioxide to form
carbaminohaemoglobin and carry it to the
lungs for exhalation
uRBC are produced in the marrow of long bones
In embryo it is produced in the spleen and
liver
In children it is produces from all the bone
marrows till age 5 yrs.

19. u The avg. Life is 120 days
u The old and worn out RBC are
broken down and destroyed in the
liver, spleen and bone marrow
u In normal person 20,000,000
RBC’s are destroyed every day.
u Abnormal increase in the number
of RBC’s is called
POLYCYTHAEMIA
u Abnormal decrease is called
ERYTHROPENIA

21. WHITE BLOOD CELLS

23. v The WBC’s are produced in the bone
marrow, lymph nodes, spleen and
liver.
v Their average life span is of two
weeks.
v The old and worn out WBC’s are
destroyed in the spleen and liver
v Leukaemia—when there is an
abnormal rise in the number of WBC
at the cost of RBC’s
v Leucopoenia is the abnormal
decrease in the number of WBCs
v Antibodies produced by the WBC’s
act like antitoxins which
neutralize the effect of the
toxins produced by the microbe.

29. FUNCTIONS OF LEUCOCYTES
1. Scavengers—Neutrophils
and Monocytes engulf
worn out cells of the body
and dead microbes and
thus act as scavengers.

30. ENGULFING THE MICROBE

31. Diapedesis—neutrophils show
amoeboid movement. They
migrate in mass towards the
site of infection, squeeze
through the blood capillary
walls to engulf and kill the
bacteria/microbe. Their ability
to squeeze out of the capillaries
is called Diapedesis.

32. DIAPEDESIS

33. Phagocytosis—on reaching
the infection site the
neutrophils and monocytes
engulf the microbes or
foreign material. The
granules of the neutrophils
are lysosomes whose enzymes
digest the engulfed
material.

35. PHAGOCYTOSIS

36. OVERVIEW OF FUNCTIONS OF
WBC

37. Pus formation—during their fight
against the foreign bodies many WBC’s
are killed, these accumulate in the
infected area and are exuded with the
plasma as pus.
Inflammation/ inflammatory reaction—
at the site of injury blood vessels release
more blood making the area red and
hot. Due to the accumulation of the
tissue fluid, the area swells up. Later on
Diapedesis and pus formation takes
place.

38. PUS FORMATION

39. INFLAMMATION

41. Formation of antibodies—lymphocytes
produce antibodies to kill the germs and
neutralize their toxins (poisons produced
by the microbe)
Confers Immunity—lymphocytes
produce antibodies to provide lifelong
immunity against certain diseases.
(Weakened /dead microbes are injected
into the body, the lymphocytes then
produce antibodies to fight against
them. The number of antibodies increase
in the blood and provide lifelong
immunity)

42. BLOOD PLATELETS
Blood platelets are minute oval structures, non-nucleated and
floating in the blood
They are derived from some giant cells called
MEGAKARYOCYTES in the bone marrow.
They are 3-4µm in diameter.
They are found 2, 00,000—3, 00,000 per cubic mm
of blood.
They live for 3-5 days.
They are destroyed in the spleen by macrophages.
They are essential for clotting of blood at the site of
injury.

43. BLOOD WITH PLATELETS
!

44. Clotting of blood
Ruptured platelets→ Thromboplastin
Prothrombin-Thromboplastin---à thrombin
Fibrinogen –Thrombinà fibrin
(Soluble) (Insoluble)
Fibrin mesh + blood cells ----à clot
A clot is also called a thrombus.
It takes 3-5 min for a clot
Blood Clot

45. Clotting of blood
Ruptured platelets→ Thromboplastin
Prothrombin-Thromboplastin---à thrombin
Inactive Ca++ Active
Fibrinogen – Thrombinà fibrin
(Soluble) Ca++ (Insoluble)
Fibrin mesh + blood cells ----à clot
A clot is also called a thrombus.
It takes 3-5 min for a clot

47. Blood contains heparin which does not allow the blood to clot
in the blood vessels. It prevents the formation of thrombin.
Heparin is produced by the basophils.
Defibrinated Blood:
Blood which does not contain the blood protein
fibrinogen is called Defibrinated blood. Without
fibrinogen blood does not clot.
Blood Blisters
They are reddish spots formed due to some injury in
which the capillaries under the skin rupture and the
blood clots under the skin. There is no external injury.
Vitamin K is essential for clotting as it is required for the
production of Prothrombin

48. BLOOD BLISTER

49. BLOOD TRANSFUSION AND BLOOD
GROUPS
ABO Blood groups
Karl Landsteiner (1900) discovered blood groups
in humans.
He divided the blood into four types A, B, AB,
and O.
Blood has antigens and antibodies
Blood group A has antigen A and antibody b
B has antigen B and antibody a
AB has antigen A and B but no antibodies
O has no antigen but has antibodies a and b

50. BLOOD GROUPS AND BLOOD
TRANSFUSION

52. In an incompatible blood transfusion, the antigen of the donated
blood is attacked by the antibody of the recipient blood plasma,
causing the blood cells to clump together.
Rh Factor:
Rhesus factor is a substance present in the red
blood cells of most people. Such people are said to
Rh+ve and those who do not have this substance
are called Rh-ve .
When Rh –ve blood is given to an Rh-ve person the
transfusion is successful.
When Rh+ve blood is given to an Rh-ve person, the
person develops antibodies against the Rh+ve blood.
When a second transfusion is given, the antibodies
will react with the Rh+ve blood and cause clumping.

53. When the father is Rh+ve and the mother is
Rh-ve the Foetus is Rh+ve. The mothers’
blood is stimulated to produce antibodies
against the Rh+ve blood. Enough antibodies
are not produced to harm the foetus.
During second pregnancy the Rh+ve foetus
could be harmed as the number of
antibodies increase and destroy the RBCs of
the foetus. This is called erythroblastosis
foetalis/ haemolytic jaundice/ anaemia in
newborns.

57. The heart is in the centre of the chest between the two lungs and
above the diaphragm.
The heart tapers towards the left side and contracts very
powerfully, and we feel the heart is towards the left side.
The heart is 12 x 9 cm in size.
It is covered by a doubled walled membrane called pericardium.
Between the two membranes is a fluid called pericardial fluid
which acts as a lubricant.
The heart consists of four chambers
Two Atria (auricle)
Two Ventricles
The walls of the atria are thinner than the walls of the ventricles
as they pump blood only till the ventricles, whereas the ventricles
have to pump blood to a greater distance.
The left ventricle has a more muscular wall than the right
ventricle as it has to pump blood to all the parts of the body and
the right ventricle till the lungs.

59. BLOOD VESSELS ENTERING AND LEAVING
THE HEART
The right atrium receives two major vessels
Anterior vena cava – brings deoxygenated blood from
the anterior parts of the body.
Posterior vena cava—brings deoxygenated blood from
the posterior parts of the body
The left atrium receives four pulmonary veins from
the lungs carrying oxygenated blood.
The right ventricle pumps the deoxygenated blood to
the lungs for oxygenation through the pulmonary
artery.
The left ventricle pumps oxygenated blood to the
parts of the body through the Aorta.
Pulmonary artery is the only artery in the body which
carries deoxygenated blood

61. From the base of the aorta
arise two coronary arteries
which supply blood to the heart
muscles. The cardiac veins
collect the deoxygenated blood
and pour it into the right
ventricles.

63. VALVES OF THE
HEART
There are four valves in
the heart which control
the flow of blood in the
heart.
1.Right Atrio- ventricular
valve/ tricuspid
(triangular leaf like
flaps/cusps held together
by chordae tendinae
which arise from the
walls of the ventricles
called papillary muscles)
2.Left Atrio—ventricular
valve/ bicuspid (two
flaps/ cusps)
3.Pulmonary semilunar
valves
4.Aortic semilunar valves
The valves prevent the
backflow of blood.

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