Lymph

Information about Lymph

The human lymphatic system

The lymphatic system is a complex network of lymphoid organs, lymph nodes, lymph ducts, lymphatic tissues, lymph capillaries and lymph vessels that produce and transport lymph fluid from tissues to the circulatory system. The lymphatic system is a major component of the immune system.

The lymphatic system has three interrelated functions: (1) removal of excess fluids from body tissues, (2) absorption of fatty acids and subsequent transport of fat, as chyle, to the circulatory system and, (3) production of immune cells such as lymphocytes (e.g. antibody producing plasma cells) and monocytes.

Lymphatic circulation

Unlike the blood system, the lymphatic system is not closed and has no central pump. Lymph movement occurs slowly with low pressure due to peristalsis, valves, and the milking action of skeletal muscles. Like veins, lymph travels through vessels in one way only, due to semilunar valves. This depends mainly on the movement of skeletal muscles to squeeze fluid through them, especially near the joints. Rhythmic contraction of the vessel walls through movements may also help draw fluid into the smallest lymphatic vessels, capillaries. Tight clothing can restrict this, thus reducing the removal of wastes and allowing them to accumulate. If tissue fluid builds up the tissue will swell; this is called edema. As the circular path through the body's system continues, the fluid is then transported to progressively larger lymphatic vessels culminating in the right lymphatic duct (for lymph from the right upper body) and the thoracic duct (for the rest of the body); both ducts drain into the circulatory system at the right and left subclavian veins. The system collaborates with white blood cells in lymph nodes to protect the body from being infected by cancer cells, fungi, viruses or bacteria. This is known as a secondary circulatory system.

Function of the fatty acid transport system

Lymph vessels called lacteals are present in the lining of the gastrointestinal tract. While most other nutrients absorbed by the small intestine are passed on to the portal venous system to drain, via the portal vein, into the liver for processing, fats (lipids) are passed on to the lymphatic system, to be transported to the blood circulation via the thoracic duct. The enriched lymph originating in the lymphatics of the small intestine is called chyle (not chyme). As the blood circulates, fluid leaks out into the body tissues. This fluid is important because it carries food to the cells and waste back to the bloodstream. The nutrients that are released to the circulatory system are processed by the liver, having passed through the systemic circulation. The lymph system is a one-way system, transporting interstitial fluid back to blood.

Pathology

In elephantiasis, infection of the lymphatic vessels cause a thickening of the skin and enlargement of underlying tissues, especially in the legs and genitals. It is most commonly caused by a parasitic disease known as lymphatic filariasis.

Lymphedema also causes abnormal swelling, especially in the appendages (though the face, neck, and abdomen can also be affected). It occurs if the lymphatic system is damaged, or underdeveloped in some way. An estimated 170 million suffer with the disorder. There are three stages:
Stage 1: Pressing the swollen limb leaves a pit that takes a while to fill back in. Because there is little fibrosis (hardening) it is often reversible. Elevation reduces swelling.
Stage 2: Pressure does not leave a pit. Elevation does not help. If left untreated, the limb becomes fibrotic.
Stage 3: This stage of lymphedema is often called elephantiasis. It is generally only in the legs after lymphema that has gone long untreated. While treatment can help a little, it is not reversible.

Development of Lymphatic Tissues

Lymphatic tissues begin to develop by the end of the fifth week of embryonic life. Lymphatic vessels develop from lymph sacs that arise from developing veins, which are derived from mesoderm.
The first lymph sacs to appear are the paired jugular lymph sacs at the junction of the internal jugular and subclavian veins. From the jugular lymph sacs, lymphatic capillary plexuses spread to the thorax, upper limbs, neck and head. Some of the plexuses enlarge and form lymphatic vessels in their respective regions. Each jugular lymph sac retains at least one connection with its jugular vein, the left one developing into the superior portion of the thoracic duct.
The next lymph sac to appear is the unpaired retroperitoneal lymph sac at the root of the mesentery of the intestine. It develops from the primitive vena cava and mesonephric veins. Capillary plexuses and lymphatic vessels spread form the retroperitoneal lymph sac to the abdominal viscera and diaphragm. The sac establishes connections with the cisterna chyli but loses its connections with neighboring veins.
The last of the lymph sacs, the paired posterior lymph sacs, develop from the iliac veins. The posterior lymph sacs produce capillary plexuses and lymphatic vessels of the abdominal wall, pelvic region, and lower limbs. The posterior lymph sacs join the cisterna chyli and lose their connections with adjacent veins.
With the exception of the anterior part of the sac from which the cisterna chyli develops, all lymph sacs become invaded by mesenchymal cells and are converted into groups of lymph nodes.
The spleen develops from mesenchymal cells between layers of the dorsal mesentery of the stomach. The thymus arises as an outgrowth of the third pharyngeal pouch.

References

External links

Lymphatic System
Lymphatic System Overview (innerbody.com)

• • [ e] Immune system / Immunology
Systems	Adaptive immune system vs. Innate immune system • Humoral immune system vs. Cellular immune system • Complement system (Anaphylatoxins)
Antibodies and antigens	Antibody (Monoclonal antibodies, Polyclonal antibodies, Autoantibody) • Allotype • Isotype • Idiotype • Antigen (Superantigen)
Immune cells	White blood cells (T cell, B cell, NK cell, Mast cell, Basophil, Eosinophil) • Phagocyte (Neutrophil, Macrophage, Dendritic cell) • Antigen-presenting cell • Reticuloendothelial system
Immunity vs. tolerance	Immunity • Autoimmunity • Allergy • Tolerance (Central) • Immunodeficiency
Immunogenetics	Somatic hypermutation • V(D)J recombination • Immunoglobulin class switching • MHC / HLA
Other	Cytokines • Inflammation • Opsonin

• • [ e] Human organ systems
Cardiovascular system • Digestive system • Endocrine system • Immune system • Integumentary system • Lymphatic system • Muscular system • Nervous system • Reproductive system • Respiratory system • Skeletal system • Urinary system

• • [ e] Immune system: Lymphatic system (Lymph, Lymphocytes)
Primary	Bone marrow - Thymus (Hassall's corpuscles)
Secondary: Spleen (blood)	Hilum - Trabeculae - Red pulp (Cords of Billroth, Marginal zone) - White pulp (Periarteriolar lymphoid sheaths)
Secondary: Lymph nodes (extracellular fluid)	Subcapsular sinus - Paracortex - Lymph vessels - High endothelial venules
Secondary: MALT (mucosa)	GALT - Peyer's patches

• • [ e] Lymphatics of head and neck
Head	Occipital - Mastoid - Parotid (Preauricular) - Buccinator - Submandibular - Submental - Retropharyngeal
Neck	Cervical (Superficial, Superior deep, Inferior deep) - Supraclavicular (Virchow's) - Paratracheal - Jugular trunk
Tonsils/Waldeyer's tonsillar ring	Palatine - Lingual - Adenoid - Tubal

• • [ e] Lymphatics of upper limbs
Axillary	brachial - pectoral axillary - subscapular axillary - central - apical
Other	supratrochlear - deltopectoral

• • [ e] Lymphatics of torso
Chest	Tracheobronchial - Right lymphatic duct - Thoracic duct (spans diaphragm)
Abdomen	Cisterna chyli - Lumbar trunk - Intestinal trunk - lumbar/paraaortic (Retroaortic, Lateral aortic, Preaortic, Inferior mesenteric) - iliac (Common, External, Internal)

• • [ e] Lymphatics of lower limbs
Deep inguinal - Superficial inguinal - Popliteal

Lymph nodes are components of the lymphatic system. They are sometimes informally called lymph glands but, as they do not secrete substances, such terminology is not entirely accurate. They are found mostly in the neck area.
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In human anatomy, the thoracic duct is an important part of the lymphatic system—it is the largest lymphatic vessel in the body.

It collects most of the lymph in the body (except that from the right arm and the right side of the chest, neck and head, which is
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Lymphatic Tissue is a specialized form of reticular connective tissue in the lymphatic system that contains large numbers of lymphocytes. ^[1] This tissue type makes up the spleen, the thymus, and the tonsils, as well as visceral nodes, peyer's patches and lacteals which are all
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Lymph capillaries or lymphatic capillaries are tiny thin-walled blood vessels that are closed at one end and are located in the spaces between cells throughout the body, except in the central nervous system, and in non-vascular tissues.
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In anatomy, lymph vessels are thin walled, valved structures that carry lymph. As part of the lymphatic system, lymph vessels are complimentary with the vascular system. In contrast to the vascular system, which carries blood under pressure to the entire body, lymph is not under
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Biological tissue is a collection of interconnected cells that perform a similar function within an organism.

The study of tissue is known as histology, or, in connection with disease, histopathology.
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Circulatory System is a psychedelic rock musical ensemble formed by musician/painter Will Cullen Hart, and featuring Hannah Jones, Derek Almstead, Peter Erchick, John Fernandes, and Heather McIntosh.
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immune system is a collection of mechanisms within an organism that protects against disease by identifying and killing pathogens and tumor cells. It detects a wide variety of agents, from viruses to parasitic worms, and needs to distinguish them from the organism's own healthy
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Chyle is a milky fluid (bodily fluid) consisting of lymph and emulsified fats, or free fatty acids (FFAs). It is formed in the small intestine during digestion of ingested fatty foods and taken up by lymph vessels specifically known as lacteals, unlike other components of digested
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lymphocyte is a type of white blood cell in the vertebrate immune system. By their appearance under the light microscope, there are two broad categories of lymphocytes, namely the large granular lymphocytes and the small lymphocytes.
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Plasma cells (also called plasma B cells or plasmocytes) are cells of the immune system that secrete large amounts of antibodies. They differentiate from B cells upon stimulation by CD4+ lymphocytes.
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A monocyte is a leukocyte, part of the human body's immune system that protects against blood-borne pathogens and moves quickly (aprox. 8-12 hours) to sites of infection in the tissues. Monocytes are usually identified in stained smears by their large bilobate nucleus.
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Peristalsis is the rhythmic contraction of smooth muscles to propel contents through the digestive tract. The word is derived from New Latin and comes from the Greek peristaltikos, peristaltic, from peristellein, "to wrap around," and stellein
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vein is a blood vessel that carries blood toward the heart. The majority of veins in the body carry low-oxygen blood from the tissues back to the heart; the exceptions being the pulmonary and umbilical veins which both carry oxygenated blood.
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In anatomy, the heart valves are valves in the heart that maintain the unidirectional flow of blood by opening and closing depending on the difference in pressure on each side. The mechanical equivalent of the heart valves would be the reed valves.
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capillary is used to describe any very narrow tube or channel through which a fluid can pass. See capillary action for details.

Capillaries are the smallest of a body's blood vessels, measuring 5-10 μm, which connect arterioles and venules, and are
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Edema
Classifications and external resources

ICD-10 R 60.9
ICD-9 782.3

DiseasesDB 9148

This page is about the medical condition. For the rock band, see Adema.

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The right lymphatic duct, about 1.25 cm. in length, courses along the medial border of the Scalenus anterior at the root of the neck. In most cases it ends in the right subclavian vein, at its angle of junction with the right internal jugular vein, although the termination can be
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In human anatomy, the subclavian veins are two large veins, one on either side of the body. Its diameter is approximately that of a man's small finger. It is divided into right and left subclavian vein.
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A lacteal is a lymphatic capillary that absorbs dietary fats in the villi of the small intestine.

The combination of fat and lymph in the lacteals is milky in appearance and called chyle.
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gastrointestinal tract (GI tract), also called the digestive tract, or the alimentary canal, is the system of organs within multicellular animals that takes in food, digests it to extract energy and nutrients, and expels the remaining waste.
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In biology the small intestine is the part of the gastrointestinal tract (gut) between the stomach and the large intestine and includes the duodenum, jejunum, and ileum. It is where the vast majority of digestion takes place.
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Portal vein can refer to:

the hepatic portal vein, a large vein that carries blood from the digestive tract to the liver and is formed by the splenic vein and superior mesenteric vein
a vein that is part of a portal venous system and connects two systems of capillary beds

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liver is an organ present in vertebrates and some other animals. It plays a major role in metabolism and has a number of functions in the body, including glycogen storage, decomposition of red blood cells, plasma protein synthesis, and detoxification.
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Chyme, also known as Chymus is the liquid substance found in the stomach before passing through the pyloric valve and entering the duodenum. It results from the mechanical and chemical breakdown of a bolus and consists of partially digested food, water, hydrochloric acid,
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