BLOOD CELLS
Blood cells are essential components of blood, circulating throughout the body to
perform vital functions. They are primarily produced in the bone marrow. The three
main types of blood cells are red blood cells, white blood cells, and platelets.
RED BLOOD CELLS (ERYTHROCYTES)
Function: The primary role of red blood cells is to transport oxygen from the lungs
to the body's tissues and to carry carbon dioxide from the tissues back to the lungs.
This is made possible by a protein called hemoglobin, which binds to oxygen.
Characteristics: In mammals, mature red blood cells are biconcave discs and lack a
nucleus, maximizing their surface area for gas exchange and flexibility to pass
through narrow blood vessels.
WHITE BLOOD CELLS (LEUKOCYTES)
Function: White blood cells are the body's primary defense against infection and
disease. They are a crucial part of the immune system, identifying and fighting off
pathogens like bacteria, viruses, and fungi.
Types: There are several types of white blood cells, each with specialized roles:
• Neutrophils: Fight bacterial infections.
• Lymphocytes: Involved in the adaptive immune response, including
producing antibodies and fighting viruses.
• Monocytes: Differentiate into macrophages, which engulf pathogens and
cellular debris.
• Eosinophils: Combat parasitic infections and are involved in allergic reactions.
• Basophils: Release histamine and other mediators involved in inflammatory
responses.
PLATELETS (THROMBOCYTES)
Function: Platelets are small, irregular-shaped cell fragments that play a critical
role in hemostasis, the process of stopping bleeding. When a blood vessel is
injured, platelets aggregate at the site of injury and help form a blood clot.
Characteristics: They are much smaller than red or white blood cells and are
essential for preventing excessive blood loss.