University of Mary Hardin-Baylor 6

Thymus and Its Functions

  • Thymus Hormone Production

    • The thymus produces the hormone thymosin.

    • Thymosin is essential for the maturation of T cells.

  • Developmental Changes

    • The thymus is largest during childhood.

    • It shrinks with age, impacting immune function.

  • Function

    • Stores immature T cells and aids in their maturation.

    • T cells produced are critical for combating pathogens; the thymus does not directly fight pathogens.

Spleen Overview

  • Location and Structure

    • The spleen is located posterior to the stomach and below the diaphragm.

    • It contains two main regions: red pulp (red blood cell graveyard) and white pulp (lymphatic cells).

  • Functions of the Spleen

    • Red pulp stores and recycles iron from red blood cells.

    • White pulp is involved in immune responses against pathogens.

  • Resilience

    • The spleen is delicate and can be easily injured, increasing the risk of infections.

    • Surgical removal is termed a splenectomy; individuals can live without their spleen, with other organs compensating its functions.

Tonsils

  • Types of Tonsils

    • Palatine Tonsils: The largest, located on either side of the throat.

    • Lingual Tonsils: Located at the base of the tongue.

    • Pharyngeal Tonsils (Adenoids): Located in the nasopharynx.

  • Function

    • Act as an initial defense against pathogens found in food and air.

    • Inflammation can occur if overwhelmed by pathogens, leading to pain and potential removal.

Peyer's Patches

  • Overview

    • Peyer's patches are lymphoid tissues located in the intestinal wall, functioning similarly to tonsils.

    • They help in the immune response by ‘remembering’ previously encountered pathogens.

  • Location and Immunological Role

    • Important for immunity in the gut, essentially preventing infections by recognizing dangerous pathogens.

Digestive and Immune Interactions

  • Appendix

    • Functionally involved in the immune response and memory cell storage.

    • Can become inflamed (appendicitis) if fecal material gets trapped, causing pain.

  • Importance of B and T cells

    • B cells produce antibodies for immune response, while T cells target infected cells.

Immune System Components

  • Pathogens

    • Types include bacteria (single-celled) and viruses (non-cellular).

  • Response Types

    • Innate Immunity: Non-specific, present at birth, involves barriers such as skin and mucous membranes.

    • Adaptive Immunity: Specific response developed after exposure to pathogens, involves memory cells.

  • MHC and Natural Killer Cells

    • Natural killer cells target cells that lack major histocompatibility complex (MHC) proteins.

  • Inflammatory Response

    • Response to injury involves increased blood flow, margination of leukocytes, and diapedesis (exit of leukocytes from blood vessels).

    • Results in redness, swelling, and warmth at the injury site as immune cells act to resolve infection.

Conclusion

  • Understanding these components helps illustrate how the body defends itself against disease and responds to injuries.