Platelets are non-nucleated spherical cells with a diameter of 2-4 microns (micrometer). These cells, along with leukocytes and platelets, belong to the blood cells. They are called platelets. In the bloodstream, the main mass is made up of mature platelets - they are approximately 87%, old cells - 4.5% and young or immature - 3.2%. The period of maturation of platelets on average lasts 8 days. Platelets stay in the bloodstream for 9 to 11 days.
The norm for men, women and children will be slightly different. In addition, depending on the age of the person, it also changes. The general blood test, along with leukocytes, hemoglobin, erythrocyte sedimentation rate (ESR) and the leukocyte formula, also includes such an indicator as platelets. The norm in men of these cells is from 180 to 400 billion per liter.
Where are they formed and destroyed?
Platelets are formed from large cells of megakaryocytes, which are almostcompletely filled with cytoplasm. They are giant red bone marrow cells. Approximately 70,000 new platelets, called platelets, are formed in the body per day. Small fragments of the cytoplasm of megakaryocytes are separated and enter the bloodstream - platelets are formed. Further, these cells mature, perform their functions and after 9-11 days are destroyed in the spleen. This organ is responsible for the exclusion from the bloodstream of shaped elements with a broken structure that have served their time.
One megakaryocyte can produce up to 8,000 platelets. For the development of these bone marrow cells in the body, a special hormone is responsible - thrombopoietin, which is synthesized in the liver, kidneys, and skeletal muscles. From there, with the blood flow, it enters the red bone marrow. And there it regulates the process of formation of megakaryocytes and platelets. With an increase in platelets in the blood, the synthesis of the hormone thrombopoietin is inhibited.
Physiological properties
Platelets play an important role in physiological processes. They perform the following functions:
- Primary stop bleeding.
- Maintaining vascular tone and permeability.
- Defensive reactions.
- Together with leukocytes, they are involved in the elimination of inflammatory processes.
- Keeping blood fluid.
But their hemostatic function is most pronounced. When a blood vessel is damaged, its lumen narrows reflexively. Platelets interact with collagen (they stick together) and forma blood clot that helps stop bleeding.
What affects platelet count?
Find out what affects such an indicator as platelets. The norm in men is slightly higher than in women and children. The number of platelets, among other things, in both children and adults is affected by age. So, in newborns, the range of platelet norm is very wide and ranges from 100 to 420 x 109/l (billion/l). This variation is due to the fact that the circulatory system of newborns is very unstable and platelets, like other blood cells, actively develop and die in them. This continues for up to a year.
The number of platelets in the blood may vary seasonally, increase after intense physical exertion and have daily fluctuations.
The norm of platelets in men, women, children
You can get acquainted with the norms of this indicator for men, women and children, depending on age, in the table below.
| Platelets | Norm in 109/l (billion per liter) |
| Men | 180-400 |
| Women | 150-380 |
| Newborn babies | 100-420 |
| Babies aged 1 to 3 months | 179-399 |
| Children ages 1 to 6 | 159-389 |
| Children aged 7 to 12 | 159-379 |
Some sources indicate that the rate of platelets inmen is up to 320 x 109/l. This is a little old data.
Platelets: the norm in men
Reduced values may be in the representatives of the stronger sex after 60 years. Depending on age, some indicators of the general blood test may change. This also applies to such an indicator as platelets. The norm for men by age of this indicator is shown in the table.
| Age of men | Norma |
| 18 to 25 years old | 179-380 |
| 26 to 35 years old | 180-400 |
| 36 to 60 years old | 179-340 |
| after 60 | up to 320 |
In adulthood, the number of platelets may become a little lower. This table clearly shows how the norm of such an indicator as platelets changes depending on age. The norm for men aged 60 is slightly reduced compared to the values of young people.
What does a high platelet count indicate?
In the general blood test, along with hemoglobin, leukocytes, ESR and the calculation of the leukocyte formula, platelets are also an important indicator. The norm in men in their blood is up to 400, in women - up to 380 x 109/l. If this figure is much higher, then this condition is called thrombocytosis. This can cause increased blood clotting. But it does not manifest itself symptomatically. It is often detected absolutely by chance - when passing a general blood test during a routine examination. Thrombocytosis can be seen withthe following states:
- Oncological processes.
- Myelofibosis.
- Chronic inflammatory processes.
- Infectious diseases.
- Postoperative period.
- Erythromyosis (chronic leukemia).
- After the removal of the spleen (splenectomy).
- For iron deficiency anemia.
- Due to long-term use of certain medications such as corticosteroids.
All of these conditions can cause an increase in such an indicator as platelets. The norm in men in their blood is usually slightly higher than in women and children. A slight increase in platelets is possible after increased physical activity. This is not a pathology. After rest, this indicator returns to normal. Thrombocytosis is primary and secondary.
Primary thrombocytosis: causes
Primary thrombocytosis occurs as a result of impaired hematopoiesis (formation and maturation of blood cells) of bone marrow stem cells. Reasons may be:
- Some form of anemia.
- Erythromia.
- Chronic myeloid leukemia.
- Fibrous degeneration of the bone marrow (myelofibrosis).
- Idiopathic thrombocythemia, with platelet counts up to 4000.
Secondary thrombocytosis: causes
Secondary thrombocytosis develops as a result of pathological conditions (diseases) that disrupt the functioning of the blood-forming organs. The most common cause of secondarythrombocytosis is an infection.
Possible causes of secondary thrombocytosis:
- Rheumatoid arthritis.
- Rheumatism (the correct name for this pathology is acute rheumatic fever).
- Osteomyelitis or purulent-necrotic process in the bone marrow.
- Ulcerative colitis.
- Severe liver disease such as cirrhosis.
- Tuberculosis.
- Tumor processes, such as carcinoma, lymphoma or Hodgkin's disease.
- Great blood loss.
- Acute hemolysis (a serious condition in which red blood cells break down).
What does a low platelet count mean?
Thrombocytopenia is a condition in which platelets are low in the blood. The norm for men in some sources is up to 320 billion cells per liter, in others - 400, and the lower limit in any case is from 180 cells. A decrease in this indicator by several times will be considered thrombocytopenia.
The reasons for this may be:
- Infectious processes.
- Functional abnormalities of the bone marrow.
- Pregnancy and menstruation in women.
- Anemia of various kinds.
- Leukemias.
- Heredity.
- Harmful effects of heavy metals.
- Alcohol in large quantities.
- Massive bleeding.
- Taking certain medications (such as antibiotics, analgesics, estrogens).
Deviations fromnormal platelet values in one direction or another requires a thorough examination and treatment not only with medications, but also with an appropriate diet.
