Lymphatic System Structures and Functions

Lymph flows from lymphatic capillaries into progressively larger lymphatic vessels, located deeper within tissues.
Lymphatic vessels, like veins, have valves to prevent the backward flow of lymph.
Larger lymphatic vessels join together to form two ducts, each draining a specific part of the body and returning lymph to the venous circulation.
Right Lymphatic Duct: Collects lymph from the right side of the head and neck, the upper right quadrant of the body, and the right arm.
- Empties into the right subclavian vein.
- The subclavian vein is the proximal part of the main vein of the arm.
Thoracic Duct: The largest lymphatic vessel in the body.
- Collects lymph from the left side of the head and neck, the upper left quadrant of the trunk, the left arm, the entire lower portion of the trunk, and both legs.
- Empties into the left subclavian vein.

Each small, bean-shaped lymph node contains specialized lymphocytes capable of destroying pathogens.
Unfiltered lymph flows into the nodes, where lymphocytes destroy harmful substances like bacteria, viruses, and malignant cells.
Additional structures within the node filter the lymph to remove other impurities.
After filtration, the lymph leaves the node and continues its journey to become part of the venous circulation again.
There are between 400 and 700 lymph nodes located along the larger lymphatic vessels, with approximately half of them in the abdomen.
Most other nodes are positioned on the branches of the larger lymphatic vessels throughout the body.

Cervical Lymph Nodes:
- Located along the sides of the neck.
- "Cervic" means neck, and "-al" means pertaining to.
- Pronunciation: (SER-vih-kal)
Axillary Lymph Nodes:
- Located under the arms in the armpit area.
- "Axill" means armpit, and "-ary" means pertaining to.
  - Pronunciation: (AK-sih-lar-ee)
Inguinal Lymph Nodes:
- Located in the inguinal (groin) area of the lower abdomen.
- "Inguin" means groin, and "-al" means pertaining to.
- Pronunciation: (ING-gwih-nal)