L14 - Lymphatic system

• What is the primary function of the lymphatic system?

  Returns fluid to vascular system
• What are the main components of the lymphatic system?

  Lymphatic vessels, lymph, and lymph nodes
• What is the role of lymphoid organs and tissues?

  They provide the structural basis of the immune system
• How do lymphatic vessels function in the body?

  They collect interstitial fluid not absorbed into blood
• What is the flow direction of lymph in the lymphatic system?

  One-way flow toward the heart
• What do lymphatic capillaries collect?

  Interstitial fluid
• Why are lymphatic capillaries highly permeable?

  Large molecules can easily pass into them
• What drains large areas of the body in the lymphatic system?

  Lymphatic trunks
• What is the function of the right lymphatic duct?

  Drains right arm and right side of head
• What is the main function of lymph nodes?

  Filter lymph and remove foreign substances
• What do afferent lymphatic vessels do?

  Carry lymph to lymph nodes
• How do efferent lymphatic vessels function?

  Carry lymph away from lymph nodes
• What mechanisms help lymphatic vessels return lymph to the circulatory system?

  Skeletal muscle pumps and valves
• What is innate immunity?

  Defenses present from birth
• What is adaptive immunity?

  Involves T and B lymphocytes
• What are natural killer (NK) cells?

  Cytotoxic innate immune cells
• What role do macrophages play in the immune system?

  Act as phagocytes and activate T cells
• Where do lymphocytes arise and mature?

  Arise in red bone marrow, mature in thymus
• What happens when B cells encounter an antigen?

  They can activate into plasma cells
• What are the steps of lymphocyte development?

  Origin, maturation, seeding, activation, proliferation
• What are the key functions of lymphoid tissue?

  • Houses lymphocytes
  • Site for lymphocyte activation and proliferation
  • Location for macrophage and lymphocyte surveillance
• Distinguish between primary and secondary lymphoid organs.

  Primary lymphoid organs:

  • Sites where T and B cells mature (e.g., red bone marrow, thymus)

  
  

  Secondary lymphoid organs:

  • Sites where immune responses occur (e.g., lymph nodes, spleen)
• What are the two main functions of lymph nodes?

  Cleanse lymph and activate the immune system
• What is the structure of lymph nodes?

  Surrounded by fibrous capsule with compartments
• What is the function of the spleen?

  Remove old RBCs and provide immune surveillance
• What are the two types of pulp in the spleen?

  Red pulp and white pulp
• What is the role of mucosa-associated lymphoid tissues (MALT)?

  Prevent pathogens from penetrating mucous membranes
• Where are Peyer’s patches located?

  In the wall of the ileum
• What is the function of the thymus?

  Maturation site for T lymphocytes
• What happens to the thymus during adulthood?

  Gradually atrophies but continues to function
• What is the significance of the higher number of afferent compared to efferent lymphatic vessels?

  Slows lymph for filtration by lymphocytes
• True or false: Lymphatic capillaries have low permeability.

  False
• True or false: The thoracic duct drains all areas of the body except the right arm.

  True
• True or false: Lymphocytes are primarily located in the white pulp of the spleen.

  True
• True or false: The thymus is the location for B cell maturation.

  False
• True or false: Peyer’s patches are a form of mucosa-associated lymphoid tissue.

  True