What is the Difference Between Tonsils and Lymph Nodes

The main difference between tonsils and lymph nodes is that tonsils are large masses of lymphoid tissue found in the walls of the pharynx and nasopharynx, and at the base of the tongue, whereas lymph nodes are small masses of confluent lymphoid follicles found along lymphatic vessels. Furthermore, tonsils are typically non-encapsulated lymphoid tissue while lymph nodes are encapsulated lymphoid tissue.

Tonsils and lymph nodes are two types of secondary lymphoid organs which allow the functional specialization of lymphocytes.

Key Areas Covered

1. What are Tonsils
     – Definition, Structure, Function
2. What are Lymph Nodes
     – Definition, Structure, Function
3. What are the Similarities Between Tonsils and Lymph Nodes
     – Outline of Common Features
4. What is the Difference Between Tonsils and Lymph Nodes
     – Comparison of Key Differences

Key Terms

Antigens, Lymph Nodes, Mucosa-Associated Lymphoid Tissue (MALT), Secondary Lymphoid Organs, T and B Lymphocytes, Tonsils

What are Tonsils

Tonsils are large, non-encapsulated or partially encapsulated masses of secondary lymphoid tissue. They lie in the walls of the pharynx and nasopharynx and at the base of the tongue. They are one of the three types of large mucosa-associated lymphoid tissue (MALT) while the other two types are the Peyer’s patches and the appendix. Here, MATL is a small concentration of lymphoid tissue found in submucosal membranes including salivary glands, oral passage, gastrointestinal tract, nasopharyngeal tract, lung, thyroid, breast, eye, and skin

Figure 1: Tonsils

Furthermore, the main function of tonsils is to filter tissue fluid in order to capture antigens. Furthermore, stratified squamous epithelium lines the luminal surface of tonsils. Beneath the epithelium, many lymphoid follicles occur with germinal centers as in lymph nodes. Here, macrophages receive the phagocytized pathogens by the epithelial cells. Macrophages present the antigens of the pathogens to the unspecialized lymphocytes, activating them. These activated cells locally secrete IgA antibodies as well.

What are Lymph Nodes

Lymph nodes are bean-shaped organs that occur along the lymphatic vessels. Around 100-200 lymph nodes occur in the human body. Most lymph nodes occur in the neck, thorax, abdomen, and pelvis. Also, they are a type of small MALT whose diameter is around 1 mm. Significantly, lymph nodes are encapsulated organs covered with dense connective tissue. These organs also contain capsular extensions of connective tissue called trabeculae, which support the blood vessels entering the lymph node.

Figure 2: Structure of a Lymph Node

Moreover, the lymph enters into the lymph node through afferent lymphatic vessels while it leaves the lymph node through efferent lymphatic vessels. The main function of lymph nodes is to filter pathogens, antigen-presenting cells, soluble antigens, and a few amounts of B cells from the lymph. Also, lymph nodes contain T and B lymphocytes, plasma cells, macrophages, and antibodies. Here, T and B lymphocytes make contact with antigens and become functionally specialized to produce an immune response specific to the antigen.

Similarities Between Tonsils and Lymph Nodes

• Tonsils and lymph nodes are two types of secondary lymphoid organs.
• Also, both are two types of mucosa-associated lymphoid tissue (MALT).
• Moreover, they contain macrophages.
• Furthermore, both allow the functional specialization of both T and B lymphocytes by coming into contact with antigens.
• Besides, both organs allow lymphocytes to contact with antigens by filtering extracellular fluids.

Difference Between Tonsils and Lymph Nodes

Definition

Tonsils refer to either of two masses of lymphoid tissue in the throat, one on each side of the root of the tongue while lymph nodes refer to the each of a number of small swellings in the lymphatic system where lymph is filtered, and lymphocytes are formed. This is the main difference between tonsils and lymph nodes.

Type of MALT

Moreover, another difference between tonsils and lymph nodes is that tonsils are large masses of MALT while lymph nodes are small masses of MALT whose diameter is less than 1 mm.

Occurrence

Furthermore, tonsils lie in the walls of the pharynx and nasopharynx and at the base of the tongue while lymph nodes occur along the lymphatic vessels.

Encapsulation

Also, tonsils are non-encapsulated or partially-encapsulated lymphoid tissue while lymph nodes are encapsulated lymphoid tissue. This is another difference between tonsils and lymph nodes.

Type of Extracellular Fluid Filtered

Finally, tonsils filter tissue fluid while lymph nodes filter lymph.

Conclusion

Tonsils are the large masses of MALT which lie in the walls of the pharynx and nasopharynx and at the base of the tongue. They filter tissue fluid to collect antigens. In comparison, lymph nodes are the small masses of MALT which occurs along the lymphatic system. Therefore, they filter lymph to collect antigens. Both tonsils and lymph nodes are two types of secondary lymphoid tissue which allow the functional specialization of lymphocytes by making them contact with filtered antigens. However, the main difference between tonsils and lymph nodes is the size, location, and the type of extracellular fluid they filter to capture antigens.

References:

1. Peckham, Michelle, et al. “The Leeds Histology Guide.” Histology Guide, 1 Jan. 1970, Available Here
2. Peckham, Michelle, et al. “The Leeds Histology Guide.” Histology Guide, 1 Jan. 1970, Available Here

Image Courtesy:

1. “Blausen 0859 Tonsils&Adenoids” By BruceBlaus. When using this image in external sources it can be cited as:Blausen.com staff (2014). “Medical gallery of Blausen Medical 2014”. WikiJournal of Medicine 1 (2). DOI:10.15347/wjm/2014.010. ISSN 2002-4436. – Own work (CC BY 3.0) via Commons Wikimedia 
2. “Lymph node” By Garland Science 2008 – Imuunobiology, 7th (CC BY-SA 4.0) via Commons Wikimedia