Internal and External Lymphoid Organs
The lymphoid organs again can be classified into two types – internal and external lymphoid organs based on their location within the body. The bone marrow, thymus, spleen, and some lymph nodes are included in internal lymphoid organs whereas all the components of MALT as well as the lymph nodes that come from MALT are included in external lymphoid organs.
The skin plays an important role in the first line of defense and is thus included in external lymphoid organs. These two types of lymphoid organs function independently in host defense. Internal lymphoid organs are responsible for a systemic immune reaction or systemic immunity whereas external lymphoid organs play an important role in local immune reaction or local immunity.
What Are Lymphoid Organs?
Lymphoid organs are part of the lymphatic system that performs many immunological functions. The lymphatic system is comprised of organs, vessels, lymph nodes, and lymph. Lymphoid organs are mainly of two types-primary and secondary lymphoid organs. The primary lymphoid organs or the central lymphoid organs such as bone marrow and thymus are the site of the maturation of lymphocytes. In contrast, the secondary lymphoid organs, also known as peripheral lymphoid organs like spleen, lymph node, etc. are associated with the initiation of adaptive immune response. In this article, we will explore lymphoid organs, types, and differences between primary and secondary lymphoid organs.
Table of Content
- What are Lymphoid Organs?
- Types of Lymphoid Organs
- Primary Lymphoid Organs and their Functions
- Secondary Lymphoid Organs and their Functions
- Tertiary Lymphoid Organs and their Functions
- Internal and External Lymphoid Organs
- Differences Between Primary and Secondary Lymphoid Organs
- What is the Function of the Lymphoid Organs?
- Diseases Associated with Lymphoid Organs