Lymph nodes

Definition

Lymph nodes are small, bean-shaped structures that filter lymph and store white blood cells to help fight infection. They are an integral part of the lymphatic system, which supports the circulatory system in maintaining fluid balance and immunity.

5 Must Know Facts For Your Next Test

1. Lymph nodes filter harmful substances from the lymph fluid before it is returned to the bloodstream.
2. They contain immune cells such as lymphocytes and macrophages that attack and destroy pathogens.
3. Lymph nodes are strategically positioned throughout the body, with clusters found in areas like the neck, armpits, and groin.
4. Swollen lymph nodes can be a sign of infection or other diseases as they become activated while fighting off pathogens.
5. The movement of lymph through the nodes relies on muscle contractions and body movements rather than a central pump like the heart.

Review Questions

• What role do lymph nodes play in filtering harmful substances from lymph fluid?
• Why might swollen lymph nodes indicate an infection?
• How does lymph move through the lymphatic system without a central pump?

Related terms

Lymph:

A clear fluid that circulates through the lymphatic system, carrying cells that help fight infections.

Lymphocytes:

A type of white blood cell found in the lymphatic system that plays a crucial role in immune responses.

Macrophages:

Large phagocytic cells found within tissues that ingest and digest pathogens and cellular debris.