Skip to content
Human Body Study

Lymphatic and Immune System

The body’s defense network and its drainage system, closely intertwined.

The lymphatic and immune system A stylised body with the lymphatic organs placed at their anatomical positions, plus two concept panels for the functional arms — innate immunity (phagocytes eating pathogens) and adaptive immunity (lymphocytes and antibodies). Each label links to the article for that part. Innate immunity fast frontline: phagocytes ingest pathogens Adaptive immunity specific and remembered: lymphocytes and antibodies Tonsils Thymus Lymph nodes Spleen Lymphatic vessels Bone marrow Lymphatic organs and lymph vessels, plus the two arms of the immune response — schematic.

Structures

Section titled “Structures”
  • Lymphatic vessels — collect leaked tissue fluid and return it to the blood.
  • Lymph nodes — filtering stations where immune cells inspect lymph.
  • Spleen — filters the blood and stores a blood reserve.
  • Thymus — where T cells mature, mostly early in life.
  • Tonsils — immune sentries at the throat and nose.
  • Bone marrow — the source of all blood and immune cells.

Two arms of defense

Section titled “Two arms of defense”
  • Innate immunity — a fast, general first line of defense.
  • Adaptive immunity — a slower, targeted response that remembers specific invaders, which is what makes vaccination possible.

What it does

Section titled “What it does”
  • Drainage — returns excess tissue fluid to the blood, preventing swelling.
  • Defense — detects and destroys microbes, toxins, and abnormal cells.

Key idea

Section titled “Key idea”

The immune system works by telling self from non-self. Most of the time this protects us; when it misfires, the result is allergy, autoimmune disease, or rejection of transplants.