The document discusses hemostasis and bleeding disorders. It describes the three stages of hemostasis: vascular contraction, platelet plug formation, and blood clot formation. Thirteen coagulation factors involved in clot formation are also listed. Mechanisms of fibrinolysis, anti-clotting, and three main types of bleeding disorders - hemophilia, purpura, and von Willebrand disease - are summarized. Hemophilia is caused by a deficiency of coagulation factor VIII, IX or XI and results in prolonged clotting time. Purpura is characterized by prolonged bleeding time and purpuric spots due to ruptured capillaries. Von Willebrand disease is caused by a deficiency of the von

1. Haemostasis
Anticoagulants
& Bleeding
Disorders
Hemophilia & purpura)

2. Stages of Hemostasis
Vascular Contraction
Platelet Plug formation
Blood clot formation
Fibrinolysis
Properties of Platelets
1. Adhesiveness
2. Activation
3. Aggregation

3. Vascular contraction
Reduces flow of blood from injured vessel.
Cause:
1- Sympathetic reflex

4. Vascular contraction-----
2-Release of vasoconstrictor
ThromboxaneA2(TXA2) &
serotonin (dense granules)
from platelets that have
adhered to the walls of
damaged vessels.

5. Platelet Plug formation: Adherence
.Platelets adhere to, exposed collagen
and von Willebrand factor
in the injured vessel wall that attract
platelets as platelets have receptors
for them on their cell membrane.

6. Platelet adhesion, Aggregation & Secretion

7. Factor I Fibrinogen
Factor II Prothrombin
Factor III Thromboplastin
Factor IV Calcium
Factor V Labile factor, or proaccelerin
Factor VI Non – existent
Factor VII Stable factor or proconvertin
Factor VIII Antihaemophilic factor / globulin A
Factor IX Christmas factor or Antihaemophilic factor B
Factor X Stuart – Prower factor
Factor XI Plasma thromboplastin antecedent or
Antihaemophilic factor C
Factor XII Hageman factor or Contact factor
Factor XIII Fibrin stabilizing factor or Laki – Lorand factor
CLOTING
FACTOR

8. CLOT FORMATION
 The clotting mechanism involves a cascade of
reactions in which clotting factors are activated.
 Most of them are plasma proteins synthesized by
the liver (vitamin K is needed for the synthesis of
factor II, VII, IX and X).
 They are always present in the plasma in an inactive
form.
 When activated they act as proteolytic enzymes
which activate other inactive enzymes.
 Several of these steps require Ca++ and platelet
phospholipid.

10. Anti - Clotting Mechanism (in vivo)
Some factors do not allow the clot enlarge beyond the
injured vessel wall one factor such is Heparin
Heparin when combined with antithrombin-III,
the effectiveness of antithrombin III to remove
thrombin increases by 100 to 1000-fold. This does not
allow the clot to extends to long .
Prevents coagulation for approximately 24 hours by
neutralizing thrombin. It facilitates action of
antithrombin III. Thus, it prevents formation of
fibrin from fibrinogen

11. Fibrinolysis (in vivo)
 The process of removing unwanted
insoluble deposit formed as a result of
coagulation is called fibrinolysis.
 It is a physiological process in which fibrin
clot is broken down by enzyme into soluble
fragment.

12. Fibrinolysis
THROMBIN+ Thrombomodulin
Protein C
Inactivate inhibitor of
plasmin activator
Generation of plasmin from
plasminogen
tPA and urokinase form
plasmin from
plasminogen

13. Plasminogen activator
plasminogen plasmin
Fibrin Soluble fibrin
fragment

14. BLEEDING DISORDERS
 Bleeding disorders are the conditions characterized by
prolonged bleeding time or clotting time.
 Bleeding disorders are of three types:
1. Hemophilia.
2. Purpura.
3. von Willebrand disease.

15. 1.Hemophilia
 Hemophilia is a group of sex-linked inherited blood
disorders, characterized by prolonged clotting time.
 However, the bleeding time is normal.
 Usually, it affects the males, with the females being the
carriers.
 Easy bruising and hemorrhage in muscles and joints
are also common in this disease

16. Causes of hemophilia
 Hemophilia occurs due to lack of formation of
prothrombin activator.
 That is why the coagulation time is prolonged.
 The formation of prothrombin activator is affected due
to the deficiency of factor VIII, IX or XI.

17. Types of hemophilia
 Depending upon the deficiency of the factor
involved,hemophilia is classified into three types:
 i. Hemophilia A (VIII)or classic hemophilia: 85%
 ii. Hemophilia B(IX) or Christmas disease: 15%
 iii. Hemophilia C or factor XI deficiency: Rare

18. Symptoms of hemophilia
i. Spontaneous bleeding.
ii. Prolonged bleeding due to cuts, tooth extraction and
surgery.
iii. Hemorrhage in gastrointestinal and urinary tracts.
iv. Bleeding in joints followed by swelling an pain
v. Appearance of blood in urine

19. 2. Purpura
 Purpura is a disorder characterized by prolonged
bleeding time.
 However, the clotting time is normal.
 Characteristic feature of this disease is spontaneous
bleeding under the skin from ruptured capillaries.
 It causes small tiny hemorrhagic spots in many
areas of the body.
 The hemorrhagic spots under the skin are called
purpuric spots (purple colored patch like
appearance).

20. Types and causes of purpura
1.Thrombocytopenic purpura
 Thrombocytopenic purpura is due to the deficiency of
platelets (thrombocytopenia).
 In bone marrow disease, platelet production is affected
leading to the deficiency of platelets.

21. 2. Idiopathic thrombocytopenic purpura
 Purpura due to some unknown cause is called
idiopathic thrombocytopenic purpura.
 It is believed that platelet count decreases due to the
development of antibodies against platelets, which
occurs after blood transfusion

22. 3.Thrombasthenic purpura
 Thrombasthenic purpura is due to structural or
functional abnormality of platelets
 However, the platelet count is normal.
 It is characterized by normal clotting time, normal or
prolonged bleeding time but defective clot retraction

23. 3. von Willebrand Disease
 von Willebrand disease is a bleeding disorder,
 characterized by excess bleeding even with a mild
injury.
 It is due to deficiency of von Willebrand factor, which
is a protein secreted by endothelium of damaged
blood vessels and platelets.
 This protein is responsible for adherence of platelets to
endothelium of blood vessels during hemostasis after
an injury.