The lymphatic and immune system

1
The lymphatic and immune system

• Fluid, vessels, cells and tissues

2
Functions of the lymphatic/immune system

• Maintaining balance between intracellular and
  extracellular fluid levels
• Transport of lipids and lipid-soluble vitamins
  (A,D, E, K)
• Immune function
• Antigen trapping
• B and T lymphocytes, antigen-presenting cells

3
Overview of the lymphatic system
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Lymphatic vessels system parallels circulatory
system

• Capillaries drain into lymphatic vessels
• Valves keep fluids moving
• Circulates through lymph nodes
• Lymphatic vessels are not present in avascular
  tissue, CNS, red bone marrow, parts of spleen

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Structure of lymphatic capillaries
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Lymphatic ducts connect lymphatic and circulatory
systems
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continued
8
Edema excess retention of interstitial fluid

• High blood pressure
• Heart disease
• Liver disease

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Organs and tissues of the lymphatic system

• Thymus
• Lymph nodes
• Spleen

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The thymus T (thymus) cells mature there
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Thymic education

• T cells migrate from bone marrow to thymus
• Most are eliminated there
• Surviving cells regulate immune response (helper
  T cells) or help control infection (cytotoxic T
  cells)
• Thymus decreases in size throughout life

12
Lymph nodes about 600 throughout body

• Tends to occur in groups (esp. mammary glands,
  axillae and groin)
• Encapsulated
• Trabeculae form compartments
• Exchange between blood and lymph

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Features of lymph nodes
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Lymph nodes filter lymph spleen filters blood
15
Spleen, continued

• White pulp (arteries)
• T and B cells, macrophages
• Red pulp(veins)
• Removal of damaged cells
• Storage of platelets
• Formation of blood cells in fetus

16
Lymphoid tissue aggregates elsewhere in the body

• MALT, GALT
• Tonsills adenoids
• Specialized immune cells are resident in other
  organs also

17
See pp. 522-529 for major groups of lymph nodes
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Important aspects of immune function

• Protection from infection (immediate and
  long-term)
• Distinguishes self from non-self
• Disorders include hypersensitivity, autoimmune
  disease, immune deficiency