Lymphatic system

Lymphatic System

• Network of vessels and tissues/organs producing immune cells.

• Components include lymph, lymphatic vessels, lymphatic tissue, and lymphatic organs.

• Lymph characteristics: clear, low in protein, contains lymphocytes, possibly debris, hormones, pathogens.

Lymphatic Vessels

• Lymph flows through lymphatic vessels, absent in CNS, cartilage, etc.

• Capillaries are closed at one end, allow for passage of fluids and immune cells.

• Lymph flow mechanisms: contraction of vessels, skeletal muscle movement, thoracic pump, and rapid bloodstream flow into subclavian veins.

Leukocytes

• Protect against infections, migrate from bloodstream to tissues.

• Types: NK cells (destroy infected/cancerous cells), T lymphocytes (thymus-dependent), B lymphocytes (produce antibodies), macrophages (phagocytize debris and pathogens).

Inflammation

• Local response to tissue injury with purposes: limit pathogen spread, remove debris, initiate repair.

• Characterized by erythema, swelling, heat, and pain.

• Involves cytokines for immune cell communication and mobilization of defenses.

Immunity

• Immune system protects against infections, deficiencies increase susceptibility.

• Types: innate (immediate response, barriers, phagocytes) and adaptive (specific and memory responses).

• Forms of specific immunity: humoral (antibody-mediated) and cellular (cell-mediated).