Blood Components and Functions Quiz

Functions and Characteristics of Blood Components

• Blood plasma contains over 100 solutes, including proteins, nonprotein nitrogenous substances, organic nutrients, electrolytes, and respiratory gases.
• The formed elements of blood include erythrocytes, leukocytes, and platelets, with white blood cells being the only complete cells.
• Erythrocytes, or red blood cells, lack nuclei and organelles, are filled with hemoglobin, and contribute significantly to gas transport due to their structural characteristics.
• Hemoglobin in erythrocytes binds reversibly with oxygen, with each molecule of hemoglobin capable of transporting four molecules of oxygen.
• Erythropoiesis, or the production of red blood cells, occurs in the red bone marrow and is controlled by the hormone erythropoietin, which is released by the kidneys in response to hypoxia.
• Erythropoiesis requires proteins, lipids, carbohydrates, iron, vitamin B12, and folic acid for optimal production of red blood cells.
• The life span of an erythrocyte is 100-120 days, after which dying erythrocytes are engulfed by macrophages and their components are recycled.
• Leukocytes, or white blood cells, are less numerous than red blood cells and can leave capillaries via diapedesis to move through tissue spaces.
• Leukocytosis, an increase in the white blood cell count, is a normal response to bacterial or viral invasion.
• Granulocytes, a type of white blood cell, include neutrophils, eosinophils, and basophils, which are all phagocytic cells with specific functions.
• Neutrophils are important in combating bacterial infections and have granules containing peroxidases, hydrolytic enzymes, and defensins.
• Eosinophils are involved in counterattacking parasitic worms and lessening the severity of allergies by phagocytizing immune complexes.

Hemostasis and Blood Transfusion Overview

• Hemostasis involves three phases: vascular spasms, platelet plug formation, and coagulation
• Platelets adhere to collagen with the help of von Willebrand factor and are stimulated by thromboxane A2
• Coagulation transforms blood from a liquid to a gel through intrinsic and extrinsic pathways
• Hemostasis disorders include thrombus (clot in a blood vessel) and embolus (freely floating thrombus)
• Substances like aspirin, heparin, and warfarin are used to prevent undesirable clots
• Whole blood transfusions are used for substantial blood loss while packed red cells are used for treating anemia
• RBCs have glycoprotein antigens on their surfaces, unique to individuals and used for blood group classification
• ABO blood group consists of two antigens (A and B) and corresponding antibodies in the plasma
• Rh blood group has eight different agglutinogens, with presence indicated as Rh+
• Hemolytic disease of the newborn occurs when Rh+ antibodies of a sensitized Rh– mother attack Rh+ baby's RBCs
• Transfusion reactions occur when mismatched blood is infused, causing diminished oxygen-carrying capacity and other issues
• Blood typing involves adding serum containing anti-A or anti-B agglutinins to blood and observing agglutination as a positive reaction