Question 1
Define the following:
1.1. DIAPEDESIS
A disorder in which red and white blood cells pass through the blood
vessel walls that house them typically accompanying inflammation,
without injuring the vessels.
1.2. ANEMIA
A pathological condition in which there is an abnormally low number of red
blood cells in the bloodstream, resulting in pallor and weariness
1.3. LEUKOPENIA
An abnormal decrease in the number of white blood cells/leukocytes in
the blood below 5000 cells per cubic millimeter which places individuals
at increased risk of infection.
1.4. LEUKEMIA
A malignant progressive disease, a cancer of blood cells, in which the
bone marrow and other blood-forming organs produce increased
numbers of immature or abnormal leucocytes. These suppress the
production of normal blood cells, leading to anemia and other symptoms.
1.5. THROMBUS
A thrombus is a stationary blood clot along the wall of a blood vessel,
frequently causing vascular obstruction. It is the final product of the blood
coagulation step in hemostasis. There are two components to a thrombus:
aggregated platelets that form a platelet plug, and a mesh of cross-
linked fibrin protein. A thrombus is a healthy response to injury intended to
prevent bleeding.
, Question 2
Describe the intrinsic pathway of initiating blood coagulation.
The intrinsic pathway of initiating blood coagulation begins with trauma to the
blood or exposure of the blood to collagen from a traumatized blood vessel
wall.
Blood coagulation or clotting takes place in 5 essential phases.
Blood trauma causes activation of factor XII and release of platelet
phospholipids. Trauma alters factor XII and platelets.
Factor XII is disturbed by contact with collagen and it converts to activate
factor XII.
Trauma damages the platelets, releases platelets phospholipids that have
lipoprotein called platelet factor 3 which has a role in clotting reactions.
Thereafter, activated factor XII acts on factor XI to activate it as well. This
reaction requires high molecular weight kininogen which is accelerated by
prekallilrein.
Thirdly, the activated factor XI then acts enzymatically on factor IX to activate
this factor as well. Activation of factor X follows as the role of factor VIII. In which,
activated factor IX + Factor VIII + Factor 3 (Platelets) activate factor X. This step
will not be possible if factor VIII or platelets are in short supply.
As in a person who has classic hemophilia, factor VIII is missing. Platelets are
the clotting factor that is lacking in the bleeding disease called
thrombocytopenia. Therefore, it is called antihemophilic factor. Calcium (Ca++)
is required for the initial three steps.
The following step includes the action of the activated factor X to form
prothrombin activator which is the role of factor V. That is, the activated factor X
combines with Factor V and platelet or tissue phospholipids to form the complex
called prothrombin activator. The prothrombin activator in turn initiates the
cleavage of prothrombin to form thrombin, thereby setting into motion the final
clotting process.
Define the following:
1.1. DIAPEDESIS
A disorder in which red and white blood cells pass through the blood
vessel walls that house them typically accompanying inflammation,
without injuring the vessels.
1.2. ANEMIA
A pathological condition in which there is an abnormally low number of red
blood cells in the bloodstream, resulting in pallor and weariness
1.3. LEUKOPENIA
An abnormal decrease in the number of white blood cells/leukocytes in
the blood below 5000 cells per cubic millimeter which places individuals
at increased risk of infection.
1.4. LEUKEMIA
A malignant progressive disease, a cancer of blood cells, in which the
bone marrow and other blood-forming organs produce increased
numbers of immature or abnormal leucocytes. These suppress the
production of normal blood cells, leading to anemia and other symptoms.
1.5. THROMBUS
A thrombus is a stationary blood clot along the wall of a blood vessel,
frequently causing vascular obstruction. It is the final product of the blood
coagulation step in hemostasis. There are two components to a thrombus:
aggregated platelets that form a platelet plug, and a mesh of cross-
linked fibrin protein. A thrombus is a healthy response to injury intended to
prevent bleeding.
, Question 2
Describe the intrinsic pathway of initiating blood coagulation.
The intrinsic pathway of initiating blood coagulation begins with trauma to the
blood or exposure of the blood to collagen from a traumatized blood vessel
wall.
Blood coagulation or clotting takes place in 5 essential phases.
Blood trauma causes activation of factor XII and release of platelet
phospholipids. Trauma alters factor XII and platelets.
Factor XII is disturbed by contact with collagen and it converts to activate
factor XII.
Trauma damages the platelets, releases platelets phospholipids that have
lipoprotein called platelet factor 3 which has a role in clotting reactions.
Thereafter, activated factor XII acts on factor XI to activate it as well. This
reaction requires high molecular weight kininogen which is accelerated by
prekallilrein.
Thirdly, the activated factor XI then acts enzymatically on factor IX to activate
this factor as well. Activation of factor X follows as the role of factor VIII. In which,
activated factor IX + Factor VIII + Factor 3 (Platelets) activate factor X. This step
will not be possible if factor VIII or platelets are in short supply.
As in a person who has classic hemophilia, factor VIII is missing. Platelets are
the clotting factor that is lacking in the bleeding disease called
thrombocytopenia. Therefore, it is called antihemophilic factor. Calcium (Ca++)
is required for the initial three steps.
The following step includes the action of the activated factor X to form
prothrombin activator which is the role of factor V. That is, the activated factor X
combines with Factor V and platelet or tissue phospholipids to form the complex
called prothrombin activator. The prothrombin activator in turn initiates the
cleavage of prothrombin to form thrombin, thereby setting into motion the final
clotting process.
