HEMOSTASIS

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HEMOSTASIS

• Dr MOHAMMED H SAIEMALDAHR
• FACULTY of Applied Medical Sciences
• _at_KAAU
• MED TECH DEP
• Room 513 ext. 21060

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HEMOSTASIS

• An overview of Haemostatic Mechanism, Platelet
  structure and function,
• Define the term hemostasis, coagulation,
  fibrinolysis, and hemorrhage.
• List the major and minor systems involved in
  maintaining hemostasis.
• Describe the events that take place in primary
  hemostasis.

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HEMOSTASIS

• List the function of the vascular system.
• Describe the major functions of the endothelium.
• Name the three structural zones of platelets.

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HEMOSTASIS OBJECTINES

• Describe the composition and functions of the
  peripheral zone, the sol-gel zone, and the
  organelle zone.
• Explain the role of platelets in the haemostatic
  process.
• List steps in platelet plug formation
• Name essential elements for the process of
  platelet adhesion.

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HEMOSTASIS OBJECTINES

• Describe the process of platelet aggregation.
• Describe the events take place in secondary
  hemostasis.
• Name the product responsible for stabilization
  of the haemostatic plug.
• List characteristics for the contact coagulation
  proteins.
• List characteristics for the prothrombin
  proteins.

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HEMOSTASIS OBJECTINES

• Interaction of the Fibrinolytic, Coagulation
  Systems and Related Pathology.
• Name the component of the coagulation and
  fibrinolytic system.
• List plasminogen activators and negative feedback
  clotting mechanisms.

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HEMOSTASIS OBJECTINES

• Describe plasmins action in forming the
  intermediate degradation product, D dimer.
• Name the primary inhibitor of the fibrinolytic
  system.
• Describe the physiologic interactions of the
  proteolytic system.

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HEMOSTASIS OBJECTINES

• Acquired coagulation disorders
• Objectives
• Following this conference, the student will be
  able to
• Explain the classification of acquired disorder
  of haemostasis such as
• Hepatic disease, vitamin K deficiency , renal
  disease, haeorrhagic disease of the newborn,
  overdosage with anticoagulant, massive
  transfusion syndrome.
• Explain the action of oral anticoagulants

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HEMOSTASIS OBJECTINES

• Acquired coagulation disorders
• Objectives
• Name the most common laboratory test used to
  monitor oral anticoagulant therapy
• List mechanisms and clinical conditions
  associated with DIC.
• Define the three generalized clinical states of
  DIC with regard to the typical
• Laboratory abnormalities associated with each
  state.
• Describe the use of laboratory tests to
  distinguish primary fibrnolysis from DIC.
• Identify therapies for treatment of DIC

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HEMOSTASIS OBJECTINES

• Quantitative and Qualitative Vascular and
  Platelet Disorders.
• Both Congenital and Acquired.
• Congenital Disorder of platelet Function
• 1- Bernard Soulier Syndrome (BSs).
• 2- Glanzmanns thrombasthenia

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HEMOSTASIS

• Objectives.
• Definition of Hemostasis
• Haemostatic components
• Concepts of Normal Hemostasis
• Role of Coagulation in Hemostasis
• Primary and Secondary
• Role of Blood Vessels in Hemostasis
• Coagulation Proteins
• Factor Nomenclature
• Coagulation Groups
• Phospholipids Contribution to Coagulation.

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Vessel wall, Blood flow Coagulation Substances
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In Case if there is an Endothelial
Injury(Bleeding must be prevented at site of
injury)
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Flow must be Maintained
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HEMOSTASIS

• Definition
• Hemostasis drives from the Greek meaning The
  stoppage of blood flow.
• There are three haemostatic components
• 1- The extra-vascular (The tissues surrounding
  blood vessels) involved in Hemostasis when local
  vessel is injured.
• It plays a part in Hemostasis by providing
  back-pressure on the injured vessel through
  swelling and trapping of escaped blood.

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HEMOSTASIS

• The three haemostatic components
• 2- The vascular (The blood vessels through which
  blood flow) it depends on the size, amount, of
  smooth muscle within their walls and integrity of
  the endothelial cell lining.
• 3- The intra-vascular (The platelets and plasma
  proteins that circulate within the blood
  vessels).
• These components are involved in Coagulation
  (clot or thrombus formation) or Fibrinolysis
  (clot or thrombus dissolution).

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HEMOSTASIS

• Concepts of Normal Hemostasis
• Under normal conditions, the formation and
  dissolution of thrombi is maintained in a
  delicate balance. (fig ).

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• Without this balance, the individual may
  experience either excessive bleeding (poor clot
  formation or excessive Fibrinolysis)
• Vaso-occlusion (uncontrolled formation of
  thrombin in vascular system, occluding vessels
  and depriving organs of blood).

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HEMOSTASIS

• There are certain conditions associated with
  excessive bleeding are referred to as
  Hypo-coagulable states.
• Such as, Hemophilia or deficiency in one of the
  plasma coagulation proteins such as factors VIII.
  
• Acquired conditions such as DIC, Liver and
  Kidney diseases.
• In addition to Coagulation promotion, vessel
  injury initiates Fibrinolysis through endothelial
  cell release of tissue Plasminogen activators
  (tPAS).
• This is to ensure that excessive coagulation does
  not occur.

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HEMOSTASIS

• Role of Coagulation in Hemostasis
• Coagulation Is the process where by on vessel
  injury, Plasma protein, Tissue factors and
  Calcium interact on the surface of the platelets
  to form a Fibrin clot.
• Platelets provide a surface for the coagulation
  reaction, and interact with fibrin to form a
  stable platelet fibrin clot.

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HEMOSTASIS

• Tissue factors (except Ca and Tissue
  Thromboplastin) normally circulate in the plasma
  as inactive proteins.
• On activation some factors form enzymatic
  proteins known as Seiren Proteases that activate
  other specific factors in the coagulation
  sequence.
• Other conditions are related to uncontrolled
  thrombosis are called Hyper-coagulable state.
  This is related to an appropriate formation of
  thrombi in the vascular vessels that occlude
  normal blood flow.

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HEMOSTASIS

• Hemostasis can be divided into two stages
• Primary and Secondary.
• Primary hemostasis includes the platelet and
  vascular response to vessel injury.
• Secondary hemostasis includes the coagulation
  factors response to such injury.
• Together, platelets, vessels, and coagulation
  factors combine to stop bleeding and allow for
  vessel repair through formation of a stable
  fibrin-platelet plug at the site of injury.

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HEMOSTASIS

• Role of Blood Vessels in Hemostasis
• Blood flows through the vascular system to and
  from all parts of the body. The vascular system
  consists of capillaries, arteries, and veins.
• Blood normally carried within vessels whose
  physical capabilities include Contraction
  (narrowing) and Dilation, which are controlled by
  the smooth muscle of the vessel media.

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HEMOSTASIS

• Vasoconstriction and Vasodilatation provide the
  means for control blood flow rate and blood
  pressure.
• Substances released from the endothelial cells
  and sub- endothelial smooth muscles also
  contribute to normal blood flow and prevent
  abnormal formation of clot.