Blood Composition and Function Quiz

Blood Composition and Function

• Adult human blood volume ranges from 4 to 6 liters, depending on size.
• Blood is approximately 5 times thicker than water.
• Blood pH is maintained between 7.35 and 7.45.
• Blood temperature is 1°C higher than body temperature.
• Blood is a colloid, meaning it contains dispersed proteins in a liquid (water) medium.

Blood Components

• Blood, when centrifuged, separates into plasma (55%), formed elements (platelets and white blood cells -1%, and red blood cells -44%.
• Hematocrit is the percentage of formed elements in blood.
  • Adult males: 42-56%
  • Adult females: 38-46%
• Plasma is 92% water, 7% plasma proteins (albumin, globulins, and fibrinogen), and 1% dissolved molecules and ions.
• Plasma proteins exert colloid osmotic pressure (COP), preventing fluid loss from blood vessels.

Plasma Proteins

• Albumin: Most abundant plasma protein (58%), produced in the liver, acts as a transportation protein.
• Globulins: Second largest group (37%), important in transport, immunity, and blood clotting (alpha and beta subtypes).
• Fibrinogen: Plays a crucial role in blood clotting (4%).

Formed Elements

• Red Blood Cells (Erythrocytes):
  • Transport oxygen and carbon dioxide.
  • Lack a nucleus, increasing hemoglobin space.
  • Average lifespan: 90-120 days.
• White Blood Cells (Leukocytes): Two groups (Granulocytes/Agranulocytes)
  • Granulocytes: (Neutrophils, Eosinophils, Basophils)
  • Agranulocytes: (Lymphocytes, Monocytes).

Granulocytes: Description and functions

• Neutrophils: Most numerous, multilobed nucleus, pale-staining granules
• Eosinophils: 1-4% of leukocytes, bilobed nucleus, reddish granules
  • Basophils: 0.5-1% of leukocytes, bilobed nucleus, blue-violet granules

Agranulocytes: Description and functions.

• Monocytes: C-shaped nucleus, 2-8% of blood leukocytes, take up residence in tissues.

• Lymphocytes: Lymphoid organs, 20-40% of blood leukocytes, dark staining, (T-cells, B-cells, and Natural Killer cells – T-cells manage immune responses, B-cells produce antibodies, and NK cells attack abnormal cells).

• Platelets: Small cell fragments, no nucleus, crucial to hemostasis (blood clotting).

Hematopoiesis

• Formation of blood cells, predominantly in red bone marrow.

Blood Types

• ABO Blood Grouping: Determined by the presence or absence of A and B antigens on red blood cells.
• Rh Factor: Determines positive or negative blood type (Rh+ or Rh-). Rh-negative mothers carrying Rh-positive babies may require RhoGAM injections.
  • Universal Donor: Blood type O.

Blood Disorders

• Anemia: Reduced red blood cell count or hemoglobin levels, characterized by symptoms like shortness of breath, pallor, and palpitations. Types of anemia include aplastic, congenital hemolytic, erythroblastic, hemorrhagic, and pernicious.
• Sickle Cell Disease: Genetic disorder resulting in abnormal hemoglobin.
• Blood Doping: Increasing red blood cell count artificially, can cause serious cardiovascular issues.
• Leukopenia: Low white blood cell count.
• Leukocytosis: High white blood cell count.
• Neutrophilia: Increased neutrophil count, often associated with bacterial infections.

Blood Clotting

• Hemostasis: Process of stopping bleeding.
  • Vascular Spasm: Initial constriction of injured blood vessels.
  • Platelet Plug Formation: Platelets adhere to collagen and aggregate to form a plug.
  • Coagulation Phase: Formation of a fibrin mesh that traps cells and forms a clot.
    • Intrinsic Pathway and Extrinsic Pathway: Two pathways that lead to clot formation.

Blood Recycling

• When blood cells die the hemoglobin from those cells is recycled by the body. The iron from hemoglobin is transported to the liver.
• The heme portion of hemoglobin, without iron, becomes bilirubin, part of bile, and is eliminated in feces.