Blood clotting

1. St. Thomas Training College
Mukkolakkal
Power point presentation
Submitted to
Mrs. Asasindhu S S
Lecturer in Natural Science
STTC, Mukkolakkal
Submitted by
SIMI S NAIR
NATURAL SCIENCE
Reg. No
STTC ,MUKKOLAKKAL

2. BLOOD CLOTTING -A defence
mechanism
Std –10
unit:6- The strategy of defence and
treatement
Topic: Blood clotting too –a defence mechanism

3. HOW BLOOD CLOTS?
• When there is a wound is formed platelets
come and adhere to the damaged surface.
• Platelets aggregate to form platelet plug.
• Platelets are now stimulated to release certain
chemical substance.
• They synthesis an enzyme called
thromboplastin.

5. Formation of thrombin
• Thromboplastin with the help of Ca2+ convert
prothrombin to thrombin.
enzyme
• Prothrombin thrombin.
Ca2+

6. • Thrombin causes the conversion of soluble
fibrinogen to insoluble fibrin.
• Fibrin polymerises into fibrin network.
• RBC &platelets get trapped in this net work
and blood clot is formed

7. Fibrinogen in the blood fibrin
Fibrin
fibrin network

8. Thus Blood clotting include 3 steps
• 1. formation of thromboplastin
• 2.conversion of prothrombin to
thrombin
• 3.conversion of fibrinogen to fibrin

9. Ca2+
• Prothrombin thrombin
thromboplastin
• Fibrinogen fibrin
RBC
Platelets
Blood clot

10. Role of platelets
– Platelets serve 3primary function.
• 1.sticking to the injured blood vessels
(platelets adherence)
• 2 .platelets aggregate to form platelet plug
(platelets aggregation)
• 3.platelets stimulated to release certain
chemical substance for the process of
coagulation

11. A Critical question for you
• What is the cause of recurrence of blood flow
even when there is aslight force on the
wounded part ? Discuss and find the answer.
THANK YOU