platelets even in the middle of the twentieth century were different names.After forty years it has been found that they are involved in thrombus formation and are relevant to blood clotting.At the same time, the Italian scientist Bitstsotsero described the structure of these cells.Soon, scientists have begun to study and platelet function.However, until now these cells have not been fully explored.
- 1 What is meant by a platelet and what their structure
- 2 What are the forms of platelet
- 3 What are the main physiological properties have platelets
- 4 Because of what changes in blood platelet counts
- 5 reasons for increasing platelets in the blood and how they reduce
What is meant by a platelet and what their structure
platelets are called nuclear-free education, which are surrounded by a membrane.They are one of the main types of blood cells, which represent some cell fragments, i.e. megakaryocytes that are produced in the bone marrow.
Formed in the bone marrow, platelet like otshnurovyvaetsya of megakaryocyte cytoplasm and then into the blood.Platelets ripe for an average of eight days.In the bloodstream, they are processed from eight to eleven days.Norm is the presence in blood from two hundred to four hundred thousand platelets in 1 ml of blood.
platelets of normal size up to a diameter of 3 to 4 microns, respectively platelet shape can also be smaller, and they are called microforms and larger size macroform being called.These cells have a round or oval shape with a smooth surface.When platelets in contact with any foreign surfaces, they become activated and then take the shape of a star.Scion of this form are called pseudopodia.
in platelets is divided into four zones.The first is called nadmembranny layer or glycocalyx.This zone serves to platelet activation.Next is the membrane that carries out the process of interaction with platelet coagulation factors.The inner layer of the membrane has a system of canals that connect the surface of the membrane and the cytoplasm.The third area is considered zone or gel matrix.In this zone, there are mitochondria, which are constantly included in plant and animal cells.They secrete granules and are involved in the synthesis processes that occur in cells.The fourth zone is called organelles area.This area contains four types of granule that accumulate clotting factors.These granules contain bubbles, some elements of the mitochondria, and the contrast of grain tubule.
The platelets are also those substances that accelerate the gradual conversion of the inactive to the active clotting factors.
Platelets contain a huge amount of proteins or proteins, amino acids and a bit less fat.In addition they are lipoprotein complexes, a small amount of ash, glycogen, calcium, sodium, potassium, copper, magnesium, iron, manganese, and other components.
What are the forms of platelet
platelet shape depends on the degree of maturity.Therefore distinguish five forms of platelets.The first category includes mature forms.Such forms in healthy humans are in the blood substantially ninety-five percent.In such platelets is pale blue area, or gialomer, and the central area with grit or granulomer.Coming into contact with another surface forms a platelet gialomer processes, which can be of various shapes and sizes.Also distinguish between the young or immature form of platelets.They are larger than mature platelets.Such forms appear in large amounts in the case of an increased work bone marrow that is often associated with blood loss.There is also the old forms, which have different forms of education and a narrow rim.These platelets have a large number of vacuoles and granules.The presence of the old forms of platelets in large numbers indicates the formation of a malignant tumor.Besides also distinguished form irritation.These platelets can be quite large and varied forms.They arise due to violation otshnurovki process of platelets from megakaryocytes.When these forms often reveal blood diseases.Last fifth form includes degenerative platelets.They are small in size.The presence of such platelet speaks about violations of hematopoiesis.
What are the main physiological properties of platelets are
The main physiological platelet properties include the tendency to adhesion, aggregation and adsorption.Adhesion is a process of platelet adhesion to solid surfaces.Aggregation is the process of platelet adhesion and integration into a single system.Adsorption - is deposited on the surface of blood coagulation factors contained in the liquid portion of blood, i.e. the plasma, and transported with the blood flow.
Platelets are often located on the periphery of all the blood flow near the walls of blood vessels.While in this arrangement, it is easier to interact with vascular cells of the inner shell, which helps to stimulate hemostatics function.
In case of damage of the blood vessel wall components it stimulates platelet adhesion reaction process and release them from the granules, which reinforce and form a powerful amplifier aggregation thromboxane A2.This reaction can also occur influence water viruses, allergic reactions and other bacteria.Because this reaction is isolated platelets calcium which in turn is able to alter the shape of platelets, then it stimulates the release of reaction and, finally, bonding activates platelets, leading to thrombus formation.
Because of what changes in the number of blood platelets
number of platelets in the blood increases due to certain blood diseases, acute infections, inflammatory diseases, or splenectomy.Increased number of platelets in the blood is called thrombocytosis.
can also manifest itself more and decrease of platelets in the blood.This process is called thrombocytopenia.This decrease occurs because of braking formation of megakaryocytes in the bone marrow, in the accumulation of a certain number of platelets in the spleen, increased platelet decay, damage and so on.
Reasons for increasing platelets in the blood and how they reduce
Thrombocytosis, or an increase in platelets in the blood, can be primary and secondary.Primary thrombocytosis result becomes the primary proliferation, or proliferation of megakaryocytes.Secondary thrombocytosis, or else it is called a jet, occurs against a background of any disease.
blood platelet count is increased due to some diseases.Primary platelets can be caused by essential thrombocythemia, chronic myeloid leukemia, and myelofibrosis eritremii.As for the secondary platelet, they cause diseases such as tuberculosis, acute rheumatic fever, cirrhosis, rheumatoid arthritis, ulcerative colitis, amyloidosis, lymphoma, acute bleeding, cancer, acute hemolysis, Hodgkin's disease, as well as post-operative condition.
Since thrombocytosis increased blood clotting, which can lead to blood clots, most often to lower the recommended blood platelet aspirin, antiplatelet agents, anticoagulants and plateletpheresis.These drugs are much lower risk of blood clots.