Blood and Immunity Quiz

Blood and Immunity

• Blood is thicker than water, and flows more slowly.
• Temperature: 38 degrees Celsius
• pH: 7.35-7.45
• 8% of total body weight
• Blood volume: 5-6 L (average male), 4-5 L (average female)

Components of Whole Blood

• Plasma (55%):
  • 91.5% water
  • 7% proteins (albumin, globulins, fibrinogen)
  • 1.5% other solutes (nutrients, electrolytes, gases, regulatory substances, waste products)
• Formed elements (45%):
  • Red blood cells (RBCs): 4.8-5.4 million per µL
  • White blood cells (WBCs): 5,000-10,000 per µL (different types)
  • Platelets: 150,000-400,000 per µL

Functions of Blood

• Transport:
  • Oxygen from lungs to tissues
  • Carbon dioxide from tissues to lungs
  • Nutrients from intestines to tissues and cells
  • Waste products from tissues to kidneys
• Regulatory:
  • Regulates body temperature
  • Regulates pH
  • Regulates water content
  • Regulates hormones and other chemicals
• Protective:
  • Circulates white blood cells, antibodies, antitoxins
  • Produces clots to prevent excessive blood loss

Plasma Constituents and Functions

• Albumin: Maintains blood osmotic pressure
• Globulins (Immunoglobulins): Antibodies that bind to antigens, forming antigen-antibody complexes
• Fibrinogen: Involved in blood clotting.
• Nutrients (Glucose, fatty acids, amino acids, cholesterol): Provide energy and building materials
• Electrolytes (Sodium, potassium, calcium, chloride, phosphorus, magnesium): Maintain fluid balance and nerve function.
• Gases (Oxygen, carbon dioxide): Essential for cellular respiration.
• Hormones and Enzymes: Involved in various bodily functions.
• Waste products (Urea, uric acid, creatinine, ammonia): Waste products need to be removed by kidneys.

Cellular Content of Blood (Blood Cells)

• Red Blood Cells (Erythrocytes):
  • No organelles or nuclei
  • Contain hemoglobin, an oxygen-carrying protein
  • Biconcave shape (increased surface area)
  • Functions include transporting oxygen, carbon dioxide and carrying blood group antigens and rh factor.
• White Blood Cells (Leukocytes):
  • Types:
    • Granulocytes (Neutrophils, Eosinophils, Basophils)
    • Agranulocytes (Lymphocytes, Monocytes)
  • Key function: Body defense and immune response
• Platelets (Thrombocytes):
  • Involved in hemostasis (stopping bleeding)
  • Form platelet plugs and blood clots
  • Involve in defense mechanisms
  • Repair blood vessels

Non-Specific (Innate) Body Defenses

• Physical and Mechanical Barriers:
  • Skin
  • Mucous membranes
  • Cilia (respiratory tract)
  • Tears and saliva
• Chemical Barriers:
  • Lysozyme (tears, saliva, mucus)
  • Acidic environment (stomach)
  • Defensins (antimicrobial peptides)
• Cellular Defenses:
  • Phagocytic cells (Neutrophils, Macrophages)
  • Natural killer (NK) cells — Target and destroy virus-infected cells and cancer cells.
• Inflammatory Response:
  • Vasodilation (increased blood flow)
  • Recruitment of immune cells
  • Cytokine and chemokine release
• Fever:
  • Inhibits pathogen growth
  • Enhances immune responses
• Complement System: A group of proteins that opsonize pathogens, form membrane attack complexes, and recruit inflammatory cells.
• Interferons: Proteins produced by virus-infected cells that interfere with viral replication and activate immune cells (NK cells and macrophages).