Chpt. 22: Lymphatic System

function of lymphatic system?

1) production, maturation, activity of lymphocytes

2) alternative transport system for nutrients, waste, lipid

3) maintain blood volume (3L/day)

what are the lymphatic tissues/organs

• lymph

• lymphocytes

• primary lymphoid organs (red bone marrow, thymus)

• secondary lymphoid organs (lymph nodes, spleen, tonsils, MALT)

• lymphatic vessels

what are the primary and secondary lymphoid organs responsible for?

• primary: production/maturation of lymphocyte

• secondary: activation of lymphocytes

list the lymphatic vessels from smallest to biggest (lymphatic…)

• capillaries

• collecting vessels

• trunk

• duct

how does the lymphatic system work as an alternative pathway?

• intertwined with blood capillaries

• reclaims tissue fluid leakage from capillaries

what are lymph nodes? (functions + characteristics)

• function: filter lymph, exist in junctions

  • ex) neck/cervical, axillary, popliteal, inguinal

1) reticular fibers (network)

2) collection of lymphocyte

3) valves

difference between Afferent vs Efferent vessels

• afferent: arriving at lymphatic vessel (3)

• efferent: exiting lymphatic vessels (2)

lymphatic drainage right vs left side

• right: via R lymphatic duct @ R internal jugular/subclavian vein

• left: via L thoracic duct @ L internal jugular/subclavian vein

what is the thymus? (functions + characteristics)

• function: maturation of T-cell

  • identify self and do not attack

• located at mediastinum

• “hormonal” organ

what is the spleen? (functions + characteristics)

• function:

  • white pulp: immune function, filter blood

  • red pulp: filters old RBC

• made of reticular tissue/fibers = weaker organ

what is mucosa-associated lymphoid tissue (MALT)?

• epithelium = covered in mucus surface

  • examples:

    • NALT (nasal)

    • GALT (gut)

    • BALT (bronchus)

what kind of pathogens are there? (2 types)

• intracellular (replicate inside cell)

• extracellular (replicate outside cell)

process of innate response to pathogens

1) phagocytosis (macrophages + neutrophils)

2) enhance phagocytosis by coating pathogen (acts as antibody)

process of adaptive response

• forms immune memory

  1) antibody optimization/production

  2) helper T-cell produce molecules to stimulate macrophage/neutrophil activity