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Lymph system

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Lymphatic system

The lymph system is a network of organs, lymph nodes, lymph ducts, and lymph vessels that make and move lymph from tissues to the bloodstream. The lymph system is a major part of the body's immune system.

Video Transcript

Lymphatics and the breast - Animation

The lymphatic system is often referred to as the body's secondary circulatory system. The lymphatic system collects excess fluid in the body's tissues and returns it to the bloodstream. Lymph formation occurs at the microscopic level. During the exchange of fluid and molecules between the blood circulation and body tissues, blood capillaries may not reabsorb all of the fluid. Surrounding lymphatic capillaries absorb the excess fluid. The fluid is then filtered and transported back by the lymphatic system into large veins near the heart. The lymphatic system can play a very worrisome role in the spread of breast cancer. Components of the lymphatic system called lymph nodes are distributed at specific locations throughout the body. There is also an extensive network of lymphatic vessels in every woman's breast tissue, which is important in regulating the local fluid balance as well as in filtering out harmful substances. The lymph vessels in the breast may inadvertently supply cancerous cells with access to a highway along which the cancerous cells can move to other parts of the body. This process is called metastasis and may result in the formation of a secondary cancer mass in a different location of the body. Regular breast self examinations can help to detect tumors earlier in their growth, hopefully before they spread quickly or metastasize.

Information

Lymph is a clear-to-white fluid made of:

  • White blood cells, especially lymphocytes, the cells that attack bacteria in the blood
  • Fluid from the intestines called chyle, which contains proteins and fats

Lymph nodes are soft, small, round- or bean-shaped structures. They usually cannot be seen or easily felt. They are located in clusters in various parts of the body, such as the:

  • Neck
  • Armpit
  • Groin
  • Inside the center of the chest and abdomen

Video Transcript

Lymph nodes - Animation

The lymphatic system is a complex network of thin vessels, valves, ducts, nodes, and organs. It helps to protect and maintain the fluid environment of the body by producing, filtering, and conveying lymph and by producing various blood cells. Lymph nodes play an important part in the body's defense against infection. The most common cause of swollen lymph nodes is infection, which might occur even if the infection is trivial or not. Afferent lymph vessels bring unfiltered fluids into the lymph node to be filtered while efferent vessels carry clean fluids away from the lymph node and to the cardiovascular system where it helps form the plasma in the blood. Overall, lymph nodes work like a biological filtering system. When the body is invaded by foreign organisms, the painful swelling sometimes felt in the neck, armpits, groin, or tonsils comes from the microorganisms being trapped inside collections of lymph cells or nodes. Eventually, these organisms are destroyed and eliminated by cells that line the walls of the lymph nodes and the swelling and pain subside.

Lymph nodes make immune cells that help the body fight infection. They also filter the lymph fluid and remove foreign material such as bacteria and cancer cells. When bacteria are recognized in the lymph fluid, the lymph nodes make more infection-fighting white blood cells. This causes the nodes to swell. The swollen nodes are sometimes felt in the neck, under the arms, and groin.

The lymph system includes the:

  • Tonsils
  • Adenoids
  • Spleen
  • Thymus

Text only

Review Date: 8/13/2020

Reviewed By

Linda J. Vorvick, MD, Clinical Associate Professor, Department of Family Medicine, UW Medicine, School of Medicine, University of Washington, Seattle, WA. Also reviewed by David Zieve, MD, MHA, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.

References

Ball JW, Dains JE, Flynn JA, Solomon BS, Stewart RW. Lymphatic system. In: Ball JW, Dains JE, Flynn JA, Solomon BS, Stewart RW, eds. Seidel's Guide to Physical Examination. 9th ed. Philadelphia, PA: Elsevier; 2019:chap 10.

Hall JE, Hall ME. The microcirculation and lymphatic system: capillary fluid exchange, interstitial fluid, and lymph flow. In: Hall JE, Hall ME eds. Guyton and Hall Textbook of Medical Physiology. 14th ed. Philadelphia, PA: Elsevier; 2021:chap 16.

Disclaimer

The information provided herein should not be used during any medical emergency or for the diagnosis or treatment of any medical condition. A licensed medical professional should be consulted for diagnosis and treatment of any and all medical conditions. Links to other sites are provided for information only -- they do not constitute endorsements of those other sites. © 1997- A.D.A.M., a business unit of Ebix, Inc. Any duplication or distribution of the information contained herein is strictly prohibited.

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Lymphatic system - Illustration Thumbnail

Lymphatic system

The lymphatic system filters fluid from around cells. It is an important part of the immune system. When people refer to swollen glands in the neck, they are usually referring to swollen lymph nodes. Common areas where lymph nodes can be easily felt, especially if they are enlarged, are the groin, armpits (axilla), above the clavicle (supraclavicular), in the neck (cervical), and the back of the head just above hairline (occipital).

Illustration

Lymphatic system - Illustration Thumbnail

Lymphatic system

Lymph nodes produce immune cells to help fight infection. They also filter the lymph fluid and remove foreign material, such as bacteria and cancer cells. They can become swollen from inflammatory conditions, an abscess, cancer, and most commonly from infection. Common areas where lymph nodes can be felt include the groin, armpit, behind the ears, back of the head, sides of the neck and under the jaw and chin.

Illustration

Lymphatic system - Illustration Thumbnail

Lymphatic system

The lymphatic system filters fluid from around cells. It is an important part of the immune system. When people refer to swollen glands in the neck, they are usually referring to swollen lymph nodes. Common areas where lymph nodes can be easily felt, especially if they are enlarged, are the groin, armpits (axilla), above the clavicle (supraclavicular), in the neck (cervical), and the back of the head just above hairline (occipital).

Illustration

Lymphatic system - Illustration Thumbnail

Lymphatic system

Lymph nodes produce immune cells to help fight infection. They also filter the lymph fluid and remove foreign material, such as bacteria and cancer cells. They can become swollen from inflammatory conditions, an abscess, cancer, and most commonly from infection. Common areas where lymph nodes can be felt include the groin, armpit, behind the ears, back of the head, sides of the neck and under the jaw and chin.

Illustration

 
 
 
 

 

 
 

 
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