8.1.4

Blood Cells

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Blood Cells

Blood is the liquid that moves through the vessels and includes plasma (the liquid portion), red & white blood cells, and cell fragments called platelets.

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Components of blood

  • Blood plasma is the dominant component of blood. It contains water, proteins, electrolytes, lipids, and glucose.
  • The cells are responsible for carrying the gases (red cells) and the immune response (white).
  • The platelets are responsible for blood clotting.
  • Tissue fluid that surrounds cells is separate from the blood. Tissue fluid is drained via the lymphatic system.
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Red blood cells

  • Red blood cells (erythrocytes) are specialized cells that circulate through the body delivering oxygen to cells.
  • They contain haemaglobin, which binds to oxygen.
  • Red blood cells are smaller than almost all white blood cells and have a biconcave shape. They have no nucleus.
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White blood cells

  • White blood cells primarily involved in the immune response to identify and target pathogens.
  • White blood cells have nuclei and do not contain haemoglobin.
  • White blood cells include neutrophils, lymphocytes, & monocytes.
    • Neutrophils are characterized by a lobed nucleus and granular inclusions in the cytoplasm. They are typically first-responders during injury or infection.
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White blood cells - 2

  • Lymphocytes, including B and T cells, are responsible for the adaptive immune response.
    • B cells differentiate into plasma cells. Plasma cells make antibodies. This process requires help from T cells.
    • Lymphocytes have a large nucleus that takes up most of the cytoplasm.
  • Monocytes differentiate into macrophages, which in turn respond to infection or injury.
    • Macrophages phagocytose invading pathogens. They are larger than lymphocytes.

Jump to other topics

1Cell Structure

2Biological Molecules

3Enzymes

4Cell Membranes & Transport

5The Mitotic Cell Cycle

6Nucleic Acids & Protein Synthesis

7Transport in Plants

8Transport in Mammals

9Gas Exchange

10Infectious Diseases

11Immunity

12Energy & Respiration (A2 Only)

13Photosynthesis (A2 Only)

14Homeostasis (A2 Only)

15Control & Coordination (A2 Only)

16Inherited Change (A2 Only)

17Selection & Evolution (A2 Only)

18Classification & Conservation (A2 Only)

19Genetic Technology (A2 Only)

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