Blood Functions and Composition Quiz

Blood and Its Functions

• Transports nutrients, gases, and wastes around the body
• Composed of 55% plasma, 45% formed elements (red blood cells, white blood cells, and platelets)

Composition of Whole Blood

• Plasma: 90% water, 10% dissolved gases, salts, minerals, nutrients, enzymes, hormones, waste, and proteins
• Physical characteristics: 5 times more viscous than water, colors due to oxygen amount in vessels, pH range of 7.35-7.45
• Blood volume: 5-6 liters in the human body

Erythrocytes (Red Blood Cells)

• Structure: biconcave shape, round sides, no nucleus and few organelles
• Function: transport oxygen around the body via hemoglobin molecules
• Production: produced in bone marrow, assist in hematopoiesis
• Fate: destroyed in the spleen after 120-day lifespan

White Blood Cells (WBCs)

Granulocytes

• Neutrophils: destroy bacteria, produced during infection
• Basophils: release histamines to dilate blood vessels
• Eosinophils: kill parasitic worms, lessen allergic reactions

Agranulocytes

• Lymphocytes: largest and spherical nucleus, found in lymph nodes, T-cells and B-cells
• Monocytes: kidney-shaped nucleus, become macrophages to attack and engulf viruses, parasites, and bacterial infections

Platelets

• Structure: made up of tiny fragments of other cells
• Function: clotting the blood when a vessel is broken
• Production: produced to clot blood

Hemostasis

• Vascular spasms: reduce blood loss by contracting blood vessels
• Platelet plug formation: platelets stick together at the wounded epithelium
• Coagulation: injured tissue releases tissue factor, interacting with platelets to produce thrombin
• Clot retraction and repair: thrombus dislodges and floats through the blood, becoming an embolus

Blood Groups

• ABO blood groups: A, B, AB, and O
• Rh blood groups: Rh positive (Rh+) and Rh negative (Rh-)
• Basis of transfusion reactions: mismatch between donor and recipient blood types