Afferent and efferent lymphatic vessels are two types of lymphatic vessels in the lymphatic system. The lymphatic system plays an important role in the immune system of the body. The lymphatic system also has two main functions: helping to balance the body’s fluid by draining excess fluid from the body’s tissue and returning it to the blood after filtering it.
The key difference between afferent and efferent lymphatic vessels is their function. Afferent lymphatic vessels bring unfiltered fluids from the body into the lymph node, while efferent vessels carry clean, filtered fluids away and back to the bloodstream.
CONTENTS
1. Overview and Key Difference
2. What are Afferent Lymphatic Vessels
3. What are Efferent Lymphatic Vessels
4. Similarities – Afferent and Efferent Lymphatic Vessels
5. Afferent vs Efferent Lymphatic Vessels in Tabular Form
6. FAQ – Afferent and Efferent Lymphatic Vessels
7. Summary – Afferent vs Efferent Lymphatic Vessels
What are Afferent Lymphatic Vessels?
Afferent lymphatic vessels convey unfiltered lymphatic fluid from the body tissues to the lymph nodes. Afferent lymphatic vessels are thin-walled tubes that carry fluid towards a central point. Afferent lymphatic vessels are only found in lymph nodes. Afferent lymphatic vessels enter at the periphery of the lymph node and open into the lymph sinuses of the cortical part.
Figure 01: Afferent Vessels
In afferent lymphatic vessels, lymph flow and cell output rates are low. Moreover, afferent lymphatic vessels contain antigen-presenting dendritic cells, T cells, and a small proportion of B cells.
Figure 01: Afferent Vessel
What are Efferent Lymphatic Vessels?
Efferent lymphatic vessels convey clear, filtered lymphatic fluid from lymph nodes to subsequent lymph nodes or into the venous system. Efferent lymphatic vessels commence from the lymph sinuses of the medullary portion of the lymph nodes. They leave the lymph nodes at the hilum to veins or greater nodes.
Figure 02: Efferent Lymphatic Vessels
Furthermore, efferent lymphatic vessels contain >98% lymphocytes with a higher proportion of B cells. They also have much higher flow and cell output rates than afferent lymphatic vessels.
Similarities Between Afferent and Efferent Lymphatic Vessels
- Afferent and efferent lymphatic vessels are two different types of lymphatic vessels.
- Both are associated with lymph nodes.
- Both contain a fluid called lymph.
- They are affected by diseases such as lymphedema and lymphangiomatosis.
Difference Between Afferent and Efferent Lymphatic Vessels
Definition
- Afferent lymphatic vessels convey unfiltered fluid containing lymphocytes and antigen-presenting accessory cells into the subcapsular and medullary sinuses of lymph nodes.
- Efferent lymphatic vessels carry clear fluid with lymphocytes and lymph plasma out of lymph nodes ultimately into the major efferent ducts and then back to the blood.
Walls
- Afferent lymphatic vessels are thin-walled.
- Efferent lymphatic vessels are thick-walled.
Found in
- Afferent lymphatic vessels are only found in lymph nodes.
- Efferent lymphatic vessels can be found in lymph nodes, thymus, and spleen.
Composition
- Afferent lymphatic vessels contain antigen-presenting dendritic cells, T cells, and a small proportion of B cells.
- Efferent lymphatic vessels contain >98% lymphocytes with a higher proportion of B cells.
Lymph Flow and Cell Output Rates
- In afferent lymphatic vessels, lymph flow and cell output rates are low.
- In efferent lymphatic vessels, lymph flow and cell output rates are high.
The following table summarizes the difference between afferent and efferent lymphatic vessels.
Summary – Afferent vs Efferent Lymphatic Vessels
Lymphatic vessels act as reservoirs for plasma and other substances, including cells that have leaked from the circular system. They also transport lymph fluid back from the tissues to the circulatory system. There are two types of lymphatic vessels: afferent and efferent lymphatic vessels. Afferent lymphatic vessels bring unfiltered fluids from the body into the lymph node, while efferent lymphatic vessels carry the clean, filtered fluid away and back to the bloodstream. This summarizes the difference between afferent and efferent lymphatic vessels.
FAQ: Afferent and Efferent Lymphatic Vessels
1. What are the major locations of lymph nodes?
- Humans have approximately 500–600 lymph nodes distributed throughout the body. Lymph nodes are located in different parts of the body, including the head, neck, thorax, abdomen, arm, and lower limbs.
2. What is the function of the lymphatic vessels in the immune system?
- The lymphatic system is a part of the immune system. The lymphatic system keeps body fluid levels in balance, defends the body against infections, and helps to drain a watery fluid called lymph from throughout the body.
3. What is the function of afferent lymphatic vessels?
- Afferent lymph vessels bring unfiltered fluids from the body into the lymph node, where they are filtered. These lymphatic vessels drain into the subcapsular sinus of lymph nodes, carrying lymph fluid and immune cells for processing.
4. What are efferent lymphatic vessels rich in?
- Efferent lymphatic vessels contain >98% lymphocytes with a higher proportion of B cells. The efferent lymphatics are enriched in antibodies.
5. What is the main function of the efferent lymphatic vessels?
- Efferent lymphatic vessels are thick-walled. Efferent lymphatic vessels start from the lymph sinuses. They carry clean, filtered fluid away and back to the bloodstream, where it helps form plasma.
Reference:
1. Haig, D M, et al. “Local Immune Responses in Afferent and Efferent Lymph.” Immunology, U.S. National Library of Medicine.
2. “Efferent Lymph Vessel.” Science Direct.
Image Courtesy:
1. “3D Medical Animation of Afferent Vessel” by Scientific Animations (CC BY-SA 4.0) via Commons Wikimedia
2. “Lymphatic system immune response” By SGUL lymres (CC BY-SA 4.0) via Commons Wikimedia
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