Red Blood Cells (Erythrocytes): These cells are responsible for the transport of oxygen from the lungs to the tissues and the return of carbon dioxide from the tissues to the lungs. They contain the protein hemoglobin, which binds oxygen. White Blood Cells (Leukocytes): These cells are part of the immune system and are involved in protecting the body against infection and disease. They can be further classified into granulocytes (neutrophils, eosinophils, basophils) and agranulocytes (lymphocytes, monocytes). Platelets (Thrombocytes): These are small cell fragments that play a key role in blood clotting and wound healing. Plasma: The liquid component of blood that carries cells and a variety of substances, including nutrients, hormones, and waste products.
