blood

• What are the four main components of blood?

  Red blood cells, white blood cells, platelets, plasma
• What is the primary role of red blood cells?

  To carry oxygen from lungs to tissues
• What pigment do red blood cells contain?

  Hemoglobin
• What happens to oxyhemoglobin in tissues?

  It splits back into hemoglobin and oxygen
• Why do red blood cells lack a nucleus?

  To provide more space for hemoglobin
• What shape do red blood cells have and why?

  They are biconcave discs for large surface area
• What percentage of blood do white blood cells make up?

  Less than 1%
• What is the role of white blood cells?

  To defend against infections
• What is one method white blood cells use to defend against pathogens?

  Phagocytosis
• How do antibodies help white blood cells?

  They bind to pathogens and help destroy them
• What do anti-toxins do?

  They neutralize toxins produced by pathogens
• Do white blood cells have a nucleus?

  Yes, they have a nucleus
• What are platelets?

  Small fragments of cells
• What is the primary function of platelets?

  To aid in blood clotting
• What happens when a cut occurs?

  Platelets rush to the wound to clot
• Why are platelets important besides clotting?

  They prevent microorganisms from entering wounds
• What is plasma?

  A pale yellow liquid that makes blood watery
• What does plasma carry?

  Nutrients, waste products, hormones, and cells
• How much blood do most adults have?

  About five liters
• What happens if blood volume drops too much?

  Insufficient oxygen delivery to tissues
• What is artificial blood?

  A blood substitute made of salt water
• What is a major benefit of artificial blood?

  It adds volume to the circulatory system
• What is a limitation of artificial blood?

  It doesn't contain red blood cells
• What is a blood transfusion?

  Receiving real blood from donors
• Why is a blood transfusion better than artificial blood?

  It contains real red blood cells