The Lymphatic/Immune System - by Presleigh Taylor

The immune/lymphatic system protects our body from infection like bacteria, dangerous viruses, even the common cold, and other pathogens our bodies encounter in the air, the food we eat, and even in water.


  • Thymus- The thymus gland where T-lymphocytes develop and mature before birth and it is most active before puberty. The thymus secretes the hormone thymosin, which starts the growth of lymphocytes and lymphoid tissue throughout the body.
  • Tonsils- The tonsils are actually masses of lymphoid tissue that are designed to filter tissue fluids in our body.
  • Spleen- The spleen contains lymphoid tissue and is made to filter our blood for example, our red blood cells.The spleen also keeps phagocytes, which engulfs bacteria and other foreign particles.
  • Appendix- People are unclear as to what the appendix does but they do know the appendix is rich in lymph tissues.
  • Lymph nodes- Lymph nodes are in many different parts of the body like the armpits, the neck, the groin, under the jaw, in the back of the head, and in some other places in the body. Lymph nodes produce immune cells to help filter bacteria and cancer out of the body.
  • Adenoid- Adenoids are lumpy clusters of spongy tissue that help us from getting sick.
  • Thoracic duct- The thoracic duct acts as a duct which lymph drains into.
  • Lymphatic vessels- The lymphatis vessels or capillaries pick up the lymph fluid and starts pumping it away from the cells.
  • Bone Marrow- Bone marrow is soft tissue found in the cavities of bones.It is the source of all blood cells. Bone marrow can regenerate blood cells in a person who has an illness such as Leukemia.
  • Peyer's Patch- The Peyer's Patch are lymphoid follicles is located in the wall of the small intestine. The are similar to the tonsils, destroying bacteria. The Peyer's Patch also generates memory lymphocytes for long term immunity.


  • Thymosin- Thymosin is secreted in the thymus. Without thymosin your Immune system would not work properly because thymosin is what develops T lymphocytes, which recognizes foreign antigens, and without T lymphocytes your Immune sysytem will not fight off disease like its suppose to.
  • Histamines- Produced by your Immune System to fight antigens and foreign bacteria or viruses.
  • Interleukins 1- Triggers the hypothalamus in the brain to readjust thermostat to raise body temperature.


  • Prostagladins- Classified as a hormone that helps regulate inflammation. Whenever someone gets an infection, a lot of what drives the respnse is prostagladins.
  • Perforin- A protein in cytotoxic T lymphocytes that creates transmembrane pores that act as ion channels.

Lines of Defense in the Immune/Lymphatic System:

  • 1st Line: Barriers- broad, external defense- skin and muus membranes act as walls or moats
  • 2nd Line: Non-specific Patrol- broad, internal defense- the leukocytes arre like "patroling soldiers"
  • 3rd Line: Immune System- specific, acquired Immunity- lymphocytes and antibodies, B Cells and T Cells


B Cell Response- Invader (foreign antigen) => tested by B Cells (in blood and lymph) => B Cells + Antibodies => Recognition => clone => plasma cells (release antibodies) => captured invaders => memory cells (reserves/ remembers invader)

T Cell Response- Infected Cell => interleukin 1 => interleukin 2 (activates killer T Cells) or Activated Macrophage => interleukin 1 => interleukin 2 (stimulates B Cells and antibodies)

Good communication:

Immune System only really works with the circulatory system because it allows immune cells pass through blood vessels to find infection

Bad Communication:

Immune System => Nervous System-Multiple sclerosis - the immune system attacks the myelin in the neurons
Immune System => Skeletal System- Inflammation in the bones
Immune System => Muscular System- attacks motor neurons in Myasthenia gravis
Immune System => Endocrine System- attacks beta cells that produce insulin for diabetes
Immune System => Digestive System- attacks gluten in the intestines which leads to over reactive response that damages tissue

‍Example of an Immune System Disease- Polio (is a viral disease that can affect nerves and can lead to partial or full paralysis)


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