Blood Overview and Functions

Blood

• Blood is a specialized connective tissue composed of formed elements (blood cells) and blood plasma.
• Average blood volume: 4-5 L in females, 5-6 L in males; circulates approximately 1000 times daily.
• Main functions include transporting oxygen and nutrients to cells and removing waste products.

Blood Plasma

• Plasma acts as the liquid medium in blood, with 91% being water; remainder consists of salts and organic molecules.
• Major plasma proteins produced by the liver:
  • Albumins (transport molecules)
  • Globulins (immune function)
  • Fibrinogen (blood clotting)
• Globulins consist of three types: alpha, beta, and gamma.

Cellular Elements of Blood

• Three main types of blood cells:
  • Erythrocytes (RBCs):
    • Biconcave, anucleate cells specialized for oxygen transport; normal count: ~5 million/ml.
    • Lifespan of about 120 days; transport carbon dioxide (CO2) via hemoglobin and bicarbonate ion.
  • Leukocytes (WBCs):
    • Larger than RBCs, nucleated, involved in immune defense; normal count: 7000/ml (range: 5000-10000).
    • Classified into:
      • Granulocytes:
        • Neutrophils: Most abundant; first responders to bacterial infections (60-70%).
        • Eosinophils: Part of allergic reactions and parasitic infections; 2-4% of WBCs.
        • Basophils: Produce histamine; 0.5-1% of WBCs.
      • Agranulocytes:
        • Lymphocytes: Second most abundant (25-35%), responsible for antibody production.
        • Monocytes: Largest WBC, eccentric kidney-shaped nucleus; normal count: 3-8%.
  • Platelets (thrombocytes):
    • Fragments that are crucial for blood clotting; protein content aids clotting.
    • Vitamin K is essential for prothrombin production, helped by colonic bacteria.

Functions of Blood

• Supports body respiration, nutrition, waste elimination, thermoregulation, immune defense, acid-base balance, and water balance.

Muscular Tissue

• Comprises three types:
  • Skeletal Muscle:
    • Striated in appearance; under voluntary control; functions to move the skeleton.
  • Cardiac Muscle:
    • Striated with intercalated discs for cell communication; cardiac cells (cardiomyocytes) typically have a single nucleus.
  • Smooth Muscle:
    • Not detailed in the text, but generally involuntary and found in walls of hollow organs.

Explore the essential components and functions of blood in this informative quiz. Learn about blood plasma, cellular elements, and the vital roles they play in transporting substances throughout the body. Perfect for students studying human biology or anatomy.