Hematopoiesis and Hemostatic Mechanisms

• The topics covered include hematopoiesis and hemostatic mechanisms, including coagulation factors, prothrombin times, thrombin, fibrinogen, and fibrin monomer.

Hematopoiesis

• The yolk sac is the primary hematopoietic organ at the beginning of embryonic life, specifically in the third week.
• By the age of 2, all bones form the hematopoietic system.
• In young adults, hematopoiesis occurs in the epiphysis of long bones such as the humerus, femur, pelvis, sternum, and cranium.
• Formed elements of blood are created in the bone marrow.
• 5 liters of blood exist in the human body
• 3 liters consist of plasma with 90% water and 2 liters consist of other formed elements.
• Red blood cells, white blood cells, and platelets form the elements of blood.

Blood Cells and Components

• Platelets have a mean life of 10 days.
• Red blood cells or erythrocytes or haematies have a mean life of 120 days.
• Red blood cells are in charge of cellular nutrition, as they carry hemoglobin and oxygen.
• White blood cells defend the body and contain neutrophils, lymphocytes, monocytes, eosinophils, and basophils.
• Platelets are responsible for blood coagulation.
• Neutrophils are a type of white blood cell responsible for activating against bacteria.
• Lymphocytes are a type of white blood cell responsible for activating against viruses.
• Eosinophils are a type of white blood cell responsible for activating against parasites.
• Hemoglobin values for women range from 13-15.
• Hemoglobin values for men range from 14-16.
• Vasospasm, platelet plug formation, blood clot formation, connective tissue proliferation, and clot destruction are in charge of the hemostatic mechanism.
• In a severe injury, platelets begin to act within 15-20 seconds.
• In a mild injury, platelets begin to act within 1-2 minutes.

Coagulation Pathways and Factors

• Factors 12, 11, 9, 8, and 10 form the intrinsic coagulation pathway.
• Factors 3, 7, and 10 form the extrinsic pathway.
• Factors 10, 5, 2, and 1 form the common pathway.
• Factor 4 activates the other factors
• Factor 4 is calcium, the only factor that acts in the cascade of coagulation.
• Factor 8 is antihemophilic A.
• Factor 9 is antihemophilic B.
• All antihemophilic factors are in the intrinsic pathway.

Immunology

• Immunity is the body's ability to defend itself against a foreign agent called an antigen.
• An antigen is a foreign agent that triggers an immune response.
• Types of immunity include innate, acquired, passive, and active.
• Innate immunity is what one is born with.
• Acquired immunity is obtained by vaccines or contact with a disease.
• Acquired immunity divides into humoral or cellular.
• Humoral acquired immunity involves lymphocytes B.
• Cellular acquired immunity involves lymphocytes T.
• Lymphocytes B's function include memory and antibody generation (immunoglobulin GAMDE) through humoral immunity.
• Lymphocyte T needs three divisions to help: T helper, T cytotoxic, T suppressor.
• T helper cells identify.
• T cytotoxic cells eliminate or attack.
• T suppressor cells control to not damage the rest of the cell.
• Innate immunity is what one is born with.
• Acquired immunity is obtained through contact or vaccines.
• Passive acquired immunity is obtained through antidotes.
• Active acquired immunity is obtained through breast milk.

Clinical Scenario

• A 17-year-old female patient presents with 3 days of fever, headache, reticular pain, and opccimial.
• Test results are: IG, G positive; IG, M negative; IG, E negative.
• Suspect dengue, but could also be due to a parasite or allergy.
• The first lymphocytes T to defend are CD4 and CD8, with natural killers as the last resort.

Macrophages

• Microcytic macrophagic system includes macrophages that can move and are already activated.
• More than 100 bacteria are in charge of phagocytizing the macrophagic system.
• Macrophages in the brain are called microglia.
• Macrophages in the lung are called dust cells.
• Macrophages in the liver are called Kupffer cells.
• Macrophages in the bone are called osteoclasts.

Anemia

• Anemia is due to a deficiency in erythropoiesis.
• Treatment involves erythropoietin injection, iron, or B complex.

Normal Values

• Platelets: 150,000 to 450,000
• White blood cells: 6,000 to 10,000
• Neutrophils: 60% to 70%
• Lymphocytes: 25% to 30%
• Other cells: 25%
• Red blood cells: 5,200,000, with a variation of ± 300,000.