Lymph system Information | Mount Sinai

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.

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).

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.

Information

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

• White blood cells, especially lymphocytes, the cells that attack bacteria in the blood and body tissues
• 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

Lymph nodes mainly store immune cells that help the body fight infection but are also places where these cells can be made. 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

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. 10th ed. Philadelphia, PA: Elsevier; 2023: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.

Last reviewed on: 7/25/2022

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

Structure and function of lymph nodes

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By Dr. Ananya Mandal, MDReviewed by April Cashin-Garbutt, MA (Editor)

The lymphatic system is basically a channel that carries a clear or whitish fluid called the lymph. This lymph aids in clearing the tissues of infective organisms, toxins etc.

The basic structure and functions of the lymphatic system can be broken into the lymph channels. The lymph nodes, lymph and other organs. (1-4)

The lymph channels

These are a network of tubes or vessels much like the blood vessels that cover all the tissues of the body.

The lymphatic channels get progressively smaller as they pass in to distant organs and tissues.

For example, the vessel at the beginning of the arm is thicker. It branches into thinner tubes that progressively become thinner and thinner as they travel up to the fingers.

At the tips of the fingers the vessels may be the thinnest with places where they may be only a few cells thick. These are called lymphatic capillaries.

The walls of the capillaries are usually single cell thick. This helps in the movement of the immunity producing cells called lymphocytes (type of white blood cells), and the toxins, germs and chemicals to move in to the lymph capillaries freely.

The arteries also branch similarly at the tips of the organs. These capillaries give out a clear fluid called the plasma. This plasma bathes the tissues and enters the lymphatic channels as lymph.

The lymph channels eventually drain at a large lymphatic vessel called the thoracic duct at the chest that drains into a blood vessel.

All the filtered fluid, salts, and proteins as well as the debris thus ends up in the blood stream.

The lymph nodes

The lymph nodes are small bean shaped glands or bulbs that tend to occur in clusters much like grapes.

Along the lymph channels reside approximately 600 lymph nodes. These act as filters that sieve off the harmful substances brought by the lymphatic channels.

The lymphatic channels of the fingers, hand and arm for example comes to be filtered at the lymph nodes that lie at the elbow and the arm pit.

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Similarly, those of the legs, toes and thighs drain and nodes behind the knees and the groin.

Lymph channels from the face, head and scalp drain at the nodes present at the back of the head, behind the ears and sides of the neck.

Some lymph nodes are located deeper within the body at the chest (between the two lobes of the lungs), around the coils of the intestines, in the pelvis etc.

The lymph nodes contain 2 regions within them – these include the cortex and the medulla.

The cortex contains collections of lymphocytes. These contain predominantly B-lymphocytes and some T-lymphocytes.

The B lymphocytes mature completely within the bone marrow while the T lymphocytes exit the bone marrow immature and attain maturity within the thymus.

The lymphatic vessels entering the lymph nodes are called afferent lymphatic vessels and those exiting are called efferent lymphatic vessels.

Lymph

This is a clear fluid that travels via the lymphatic channels. This contains fluid, debris, chemicals, toxins, bacteria, viruses and lymphocytes on its way back from the tissues.

Other organs and the lymphatic system

The lymphatic system also consists of other organs like the spleen that lies on the above left sided part of the abdomen.

It acts like a large filter to remove worn out and damaged red blood cells from the blood and recycle them.

The spleen also contains B lymphocytes and T lymphocytes. When blood passes through the organ these cells pick up the infections.

The lymphatic system also contains the thymus that lies behind the chest bone.

The thymus is a maturation site for T lymphocytes.

Tonsils and adenoids are also part of the lymphatic system. The lie at the back of the throat. These are sentinels that protect the digestive system and the lungs from bacteria and viruses.

Function of the lymphatic system

Functions of the lymphatic system include (3):

• Drainage of fluid from blood stream into the tissues – The circulating blood through narrow vessels leads to leakage of fluid or plasma into the tissues carrying oxygen and nutrients to the tissues and carrying waste materials from the tissues into the lymph channels.

  The leaked fluid drains into the lymph vessels. This forms a circulatory system of fluids within the body.

• Filtration of the lymph at the lymph nodes – The nodes contain white blood cells that can attack any bacteria or viruses they find in the lymph as it flows through the lymph nodes.

  The cancer cells may also get trapped similarly at the lymph nodes and thus lymph nodes act as indicators of how far the cancer has already spread.

• Filtering blood – This is done by the spleen. The spleen filters out bacteria, viruses and other foreign particles.
• Raise an immune reaction and fight infections – The lymphatic system especially the lymph nodes are over active in case of an infection the lymph nodes or glands often swell up in case of a local infection.

Sources

1. www.cancerquest.org/anatomy-lymphatic-system.html
2. http://www.cancer.org/Cancer/CancerBasics/lymph-nodes-and-cancer
3. cancerhelp.cancerresearchuk.org/…/the-lymphatic-system
4. http://emedicine.medscape.com/article/937855-overview

Further Reading

• All Lymph Node Content
• What are lymph nodes?
• Swollen lymph nodes
• Lymph nodes and disease
• Lymph node Removal

Last Updated: Jun 5, 2019

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Suggested Reading

Onco Wiki – How is the skin structured?

Skin is the largest organ in our body. The skin consists of several layers, each of which has its own peculiarity and plays its own biological role. What are these layers?

• Epidermis
• Derma
• Subcutaneous fat

The role of the epidermis and intermediate layers. The epidermis takes on the entire impact of the adverse effects of the external environment. The most “injured” areas of the skin – the palms and feet – are covered with an extensive stratum corneum of the epidermis – scales into which keratinocytes turn during their natural development, in other areas the severity of the stratum corneum is less pronounced.

Below the epidermis is the dermis (lat. dermis – skin). It contains:

• blood and lymph vessels;
• sebaceous and sweat glands;
• hair follicles;
• macrophages and antigen-presenting cells that trigger an immune response upon contact with foreign microorganisms.

Deeper under the dermis lies a layer of subcutaneous fat. It contains adipose tissue that performs many important functions.

Lymph. Fluid is exchanged between blood and tissues. Lymph is the filtrate (liquid) that has been filtered (“left”) from the blood into tissues and which contains leukocytes and antigen-presenting cells

Lymph returns to the blood vessels, but along with it takes away the metabolic products of cells and tissues – proteins , carbohydrates, fats and excess fluid that are not needed by skin tissues, but which may be useful to other organs and tissues.

With lymph, metabolic products of cells and tissues, as well as lymphocytes, leak into the lymph nodes – according to this mechanism, lymphocytes that provide an immune response and metabolic products return to the blood for further use by the body (recycling). But how does it happen?

Lymph nodes. Lymphatic vessels collect lymph from organs and tissues, and the skin is no exception. Lymphatic vessels drain into the lymph nodes.

Lymph nodes are collectors (“collectors”) of lymph, the place where lymphatic vessels flow from a certain part of the body.

Lymph nodes are scattered throughout the body. They can be found along the course of large blood vessels, where they gather in groups: axillary, inguinal, cervical, popliteal, elbow, lymph nodes that collect lymph from internal organs – etc.

Even larger lymphatic vessels start from the lymph nodes, flow into even larger vessels and collect into even larger lymph nodes. Ultimately, they all flow into the neck veins.

Unfortunately, tumor cells can also enter the lymph nodes through the lymphatic system. Therefore, with melanoma, sometimes they resort to removing not only the primary tumor of the skin, but also the lymph nodes.

• The skin consists of several layers (epidermis, dermis, subcutaneous fat).
• Fluid is exchanged between blood and tissues. Lymph is the filtrate (liquid) that has been filtered (“left”) from the blood into the tissues and which contains leukocytes and antigen-presenting cells.
• Lymph returns to the blood, but through a separate system of lymphatic vessels and lymph nodes (lymph collectors).
• Lymphatic vessels gather into lymph nodes.
• Together with lymph, both leukocytes and tumor cells can be transported. Therefore, with melanoma of the skin, it is sometimes necessary to remove the lymph nodes.

Grigoriy Chizh

Oncologist, chemotherapist, graduate of the Higher School of Oncology

July 27, 2022

Understanding your lymphatic and immune systems

Our lymphatic system is an important network of vessels, lymph nodes and organs that work together to to support our health. It is an important part of our immune system, and neither our immune nor lymphatic systems can function without each other.

On this page we will provide an overview of what our lymphatic and immune systems are and what they do to keep us healthy.

On this page:

What does the lymphatic and immune systems consist of?

Our lymphatic system consists of:

• Lymph node
• Lymphatic vessels
• Lymphocytes (a type of white blood cell)
• Organs including ours:
  9 0007 Bone marrow
  • Thymus
  • Tonsils and adenoids
  • Appendix
  • Spleen.

Our immune system consists of:

• Lymphatic system
• Physical barriers such as skin, mucous membranes and stomach acid.
• Antibodies (produced by B-cell lymphocytes)
• All leukocytes, including: macrophages
• dendritic cells
• lymphocytes

How do our lymphatic system and immune system work together?

Our immune system is made up of all the cells and parts of our body that actively protect us from germs or damage that leads to infection and disease. Our white blood cells actively fight microbes, recognize, repair or destroy damaged cells. Our skin, mucous membranes, and the acids in our stomach work to provide a barrier that prevents germs from entering or spreading throughout our body.

Our lymphatic system, however, is the transport network (lymphatic vessels and lymphatic fluid) for our immune system and helps move all of our immune cells through our body, as well as remove any waste products from immune function. It also provides locations in our body (lymph nodes and organs) where the immune system does its job.

Learn more about our immune system

Our immune system has two main functions: innate immunity and adaptive immunity. These two functions work well to provide immediate and long-term protection against germs and damage that cause infection and disease.

Innate immunity

Innate immunity is the immunity we are born with. It includes physical barriers, as well as some of our white blood cells, which immediately recognize cells that are damaged or do not belong to us (germs) and begin to fight them.

Physical barriers

Skin – Our skin is the largest organ of our body. It protects us by creating a physical barrier that prevents most germs from entering our body. When we cut ourselves, break or shed our skin, we are at increased risk of infection due to the germs that can enter our bodies.

Mucous membranes – Sometimes we can breathe in germs. In these cases, we have mucous membranes lining our nose and airways that trap germs and allow our immune cells to trap and attack them. We have similar mucous membranes lining other parts of our body that work in the same way.

Stomach acids – If we eat food that contains germs, our stomach acid is designed to kill germs. This helps prevent illness or food poisoning.

White cells – Most of our white blood cells, with the exception of lymphocytes, are part of our innate immunity. Their job is to quickly recognize any cell or organism that appears to be unwanted and launch an attack. They are not very specific, but act quickly. Once they fight a germ, they send signals to our adaptive immune cells to let them know to come and join the fight or take notes and take notes. memories (see adaptive immunity) to better prepare to fight the infection if it comes back.

The most common white blood cells in your innate immune system that you have ever heard of are your neutrophils . They are the workhorse of your innate immunity, but they can be reduced if you have lymphoma or CLL. Their treatment can also lower the number of neutrophils, which increases the risk of infection. When you have a low neutrophil count, it’s called neutropenia.

Adaptive (acquired) immunity

Our adaptive immunity is also called adaptive immunity because we are not born with it. Instead, we acquire (or develop) it as we go through life and are exposed to different types of microbes. This is often referred to as our “immunological memory” because our adaptive immunity remembers infections we have had in the past and stores some very specialized cells called memory B cells or memory T cells in our lymph nodes and lymph organs.

If we get the same germs again, our memory cells go into action with a very specific and precise attack to fight the germ before it has a chance to make us sick. But each of our memory cells recognizes only one microbe, which means that they do not fight as often as our innate immune cells, but fight those microbes that remember are much more effective.

The main cells of our adaptive immunity are the same cells that become cancerous in lymphoma or CLL. Lymphocytes .

Antibodies (immunoglubulins)

The most mature types of B cells are called plasma B cells and they produce antibodies to fight infections. Antibodies are also called immunoglobulins. Because lymphoma and CLL can affect your B cells, some people may have lower antibody levels and be more prone to the disease. In this case, you may be given an antibody infusion called I NTRA V enough I mmuno G lubulins – IVIG received from a donor.

Vaccines work by activating our adaptive immunity. By exposing us to a very small dose, or an inactivated portion of a microbe that is not enough to make us sick, it helps our adaptive system recognize and create memory cells to fight infection should we encounter one in the future.

Learn more about each part of your lymphatic and immune systems by clicking on the headings below.

Lymph Node

What a lymph node looks like inside.

Lymph nodes are also sometimes referred to as lymph nodes. Most of the time you won’t be aware of your lymph nodes, but if you’ve ever had a swollen lump in your neck or jaw line during an ear or throat infection, it was a swollen lymph node. Your lymph nodes swell as your immune cells begin to fight and destroy the germs that are causing the infection. Microbes enter the lymph node, where they are destroyed and removed from the body.

Most of our lymphocytes are in our lymph nodes and lymph organs, but we may also have other immune cells in our lymph nodes.

Often the first sign of lymphoma is swelling or swelling because the lymph node fills with cancerous lymphocytes and begins to swell.

A common symptom of lymphoma includes swollen lymph nodes/nodes.

Lymphatic vessels and lymphatic fluid

Our lymphatic vessels are a network of “roads” connecting all of our lymph nodes and lymphatic organs together. They are the main transport network for moving immune cells around the body and removing waste products from damaged or diseased cells.

Our lymphatics contain a clear fluid called lymph, which helps immune cells to easily pass through our lymphatics. It also has an important immune function as it traps bacteria and transports them to the lymph nodes so they can be destroyed.

Lymphocytes and Antibodies

Lymphocytes are a type of white blood cell that fight infection and disease. These include B cells, T cells, and natural killer (NK) cells, which are produced in our bone marrow before reaching our lymphatic system.

Lymphocytes differ from other white blood cells in how they fight infection. They are part of our adaptive immunity .

Most of the time you don’t even know you’ve come into contact with germs because your lymphocytes and other immune cells fight them off before they can make you sick.

Some lymphocytes live in different parts of our body. They cluster in the lining of some of our organs so that if any microbes enter those organs, the lymphocytes can step in and stop them from causing an infection. Some areas of our body that have these groups of lymphocytes include:

• • intestinal tract (gut) – these are often referred to as Peyer’s patches.
  • respiratory tract (lungs and respiratory tract)
  • reproductive organs (including uterus, testicles and related organs and tubes)
  • urinary tract (kidneys, bladder and associated tubes).

B cells

B cells live mainly in our lymph nodes and spleen. Mature B cells produce a special protein called immunoglobulin, otherwise known as an antibody, which is very effective in fighting infections and diseases.

B cells are often found in the lymphatic system and only become active when they are alerted to an infection they need to fight.

T cells

Most of our T cells are produced before we reach adulthood and leave our bone marrow as very immature cells. They move to our thymus, where they continue to grow and mature. Often, they rest and only reactivate when there is an infection they need to fight.

T cells can also be found in our lymph nodes, spleen and other areas of our lymphatic system, but in smaller numbers.

Natural killer cells are a specialized type of T cells that are involved in both our innate and adaptive immunity , so they are all the time more active and often travel through our body looking for any signs of infection or disease with which need to fight.

Lymphocytes are the cells that become cancerous in CLL lymphoma.

But because they live primarily in our lymphatic system and not in our bloodstream, you can often have normal blood tests even if you have lymphoma.

Bone marrow

Blood cells, including red blood cells, white blood cells and platelets, are produced in the softer spongy middle part of bones.

Our bone marrow is the spongy material in the middle of our bones. Its job is to make all of our blood cells, including red blood cells, platelets, and all of our white blood cells.

Thymus

Our thymus is a butterfly-shaped organ that sits just below our sternum (breast bone). This is the main organ of the lymphatic system where T cells go after they leave the bone marrow. Once in the thymus, T cells continue to mature and then remain dormant until they are needed to fight infection.

Tonsils and Adenoids

Our tonsils are lymph nodes located at the back of the throat, one on each side. Adenoids are located in the back of the nasal cavity. Both of them work to prevent germs from entering our body. They often swell when we have a sore throat or a respiratory infection.

Spleen

Our spleen is a lymphatic organ that sits just below the diaphragm. This is where many of your B-cell lymphocytes live and make antibodies. Our spleen also helps filter our blood by breaking down old and damaged cells to make room for new healthy cells. It also stores other white blood cells and platelets that help blood clot. You can see the location of the spleen in the picture of the lymphatic system at the top of this page.

What else does our lymphatic system do?

Our lymphatic system performs three main functions, including:

Circulating and Regulating Fluid

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Every day, a small amount of fluid leaks out of our bloodstream. If this fluid stays in our tissues outside of our bloodstream, we can swell up and get swollen feet or hands (this swelling is called edema). Our lymphatic system collects this excess fluid and returns it to the bloodstream or helps us remove it from the body when we go to the bathroom to prevent swelling.

Absorbent Fats

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Some fats in the foods we eat are too large to be picked up and transferred from our digestive system to the bloodstream. Instead, our lymphatic system collects these fats in the digestive system and transports them into the bloodstream, where they can be used for energy. This is done through special lymphatic vessels in the lining of our digestive system called lactiferous vessels.

Protecting Our Body from Infection and Disease

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Supports our immune system by transporting immune cells throughout the body and moving harmful microbes or damaged and diseased cells to our lymph nodes and lymph organs for destruction and removal from our body. Our B-cell lymphocytes also produce antibodies to fight infection and disease. They do this in our spleen and other lymphatic organs.

Where does lymphoma start?

Because our lymphocytes can travel anywhere in our body, lymphoma can also start anywhere in our body. It most often starts in the lymph nodes or other parts of the lymphatic system. However, it can sometimes start in other places, including the skin, lungs, liver, brain, or spinal cord.

Nodular lymphoma is when the lymphoma is in your lymph nodes or other parts of your lymphatic system.