Lymphatic System

• What does the lymphatic system protect the body against?

  Pathogens like viruses, bacteria, and parasites
• What is one of the principal functions of the lymphatic system?

  Defend against disease-producing microbes
• What do lymphatic vessels drain from tissue spaces?

  Excess interstitial fluid
• Why is draining excess interstitial fluid important?

  It maintains circulating blood volume
• What do lymphatic vessels transport from the digestive canal?

  Dietary lipids and lipid-soluble vitamins
• How does lymphatic tissue respond to pathogens?

  It initiates specific immune responses
• What is the detrimental effect of excessive interstitial fluid accumulation?

  Increases diffusion distance for nutrients
• What is the flow direction of lymph through a lymph node?

  Enters via afferent vessels, exits via efferent vessels

  
• What does lymph fluid contain?

  Proteins, minerals, fats, and damaged cells
• How is lymph flow facilitated?

  By thoracic pressure and muscle contractions
• What role do lymph nodes play in the lymphatic system?

  They filter foreign substances from lymph
• What is the size range of lymph nodes?

  1 to 25 mm in length
• What structure covers lymph nodes?

  A capsule of dense connective tissue
• What divides the interior of a lymph node into compartments?

  Trabeculae
• What are the two main parts of the parenchyma of a lymph node?

  Superficial cortex and deep medulla

  
• Where do T cells reside in a lymph node?

  Inner cortex
• Where do B cells reside in a lymph node?

  Outer cortex
• What are the major types of lymph nodes in the body?

  • Submental
  • Submandibular
  • Cervical
  • Subclavian
  • Axillary
  • Mediastinal
  • Cubital
  • Abdominal
  • Iliac
  • Superficial Inguinal
  • Popliteal
• What do submental lymph nodes collect lymph from?

  Lower lip, floor of mouth, apex of teeth
• What do submandibular lymph nodes collect lymph from?

  Cheeks, upper lip, anterior tongue
• What do axillary lymph nodes drain?

  Lateral quadrants of the breast and upper limbs
• What do mediastinal lymph nodes surround?

  Pericardium, thymus, major heart vessels
• What do abdominal lymph nodes drain?

  Stomach, duodenum, liver, pancreas
• What do superficial inguinal lymph nodes drain?

  Anal canal, lower extremities, vulva
• What are the functions of the lymphatic system?

  • Drains excess interstitial fluid
  • Transports dietary lipids
  • Initiates immune responses
• What happens to fluid that does not return to capillaries?

  It becomes interstitial fluid
• What can a build-up of interstitial fluid lead to?

  Decreased blood volume and pressure
• What is lymphedema?

  Build-up of fluid causing tissue swelling
• What can cause lymphedema?

  Infection, injury, cancer, or radiation
• Why is lymphedema common in breast cancer patients?

  Due to removal of axillary lymph nodes
• What does the lymphatic system facilitate during fat absorption?

  Absorption of fatty acids and vitamins
• What are chylomicrons?

  Lipoproteins formed from fatty acids
• How does the body defend against pathogens?

  Through external and internal lines of defense
• What does the epidermis do in pathogen defense?

  Provides a physical barrier for microbes
• What role does mucus play in pathogen defense?

  Traps microbes and foreign substances
• What happens when pathogens penetrate barriers?

  They encounter the second line of defense
• What do antimicrobial substances do?

  Discourage microbial growth and replication
• What are the two major types of phagocytes?

  Neutrophils and macrophages
• What is the purpose of inflammation?

  Dispose of microbes and foreign materials
• What does fever do in the immune response?

  Intensifies effects of antimicrobial substances