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Encyclopedia > 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 part of the immune system. Image File history File links Question_book-3. ... Image File history File linksMetadata Illu_lymphatic_system. ... Image File history File linksMetadata Illu_lymphatic_system. ... Lymph nodes are components of the lymphatic system. ... In human anatomy, the thoracic duct is an important part of the lymphatic system — it is the largest lymphatic vessel in the body. ... Lymphatic Tissue is a specialized form of reticular connective tissue in the lymphatic system that contains large numbers of lymphocytes. ... Lymph capillaries or lymphatic capillaries are small thin-walled blood vessels which are located all over the body except in the central nervous system. ... In anatomy, lymph vessels are thin walled, valved structures that carry lymph. ... Biological tissue is a collection of interconnected cells that perform a similar function within an organism. ... For transport in plants, see Vascular tissue. ... A scanning electron microscope image of a single neutrophil (yellow), engulfing anthrax bacteria (orange). ...


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. [1] Chyle is a milky fluid (bodily fluid) consisting of lymph and emulsified fats, or free fatty acids (FFAs). ... A scanning electron microscope (SEM) image of a single human lymphocyte. ... Plasma cells (also called plasma B cells or plasmocytes) are cells of the immune system that secrete large amounts of antibodies. ... Monocyte A monocyte is a leukocyte, part of the human bodys immune system that protects against blood-borne pathogens and moves quickly (aprox. ...

Contents

Discovery

Olaus Rudbeck Sr. of Sweden (1630–1702) was a university dean, natural scientist, archaeologist and more. In 1652 he discovered the lymphatic system. He pointed to these as the source of production of white blood cells. Olaus Rudbeck, painted in 1696 by Martin Mijtens the Elder. ...


Lymphatic circulation

Unlike the cardiovascular system, the lymphatic system is not closed and has no central pump. Lymph movement occurs 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. Peristalsis is the rhythmic contraction of smooth muscles to propel contents through the digestive tract. ... In the circulatory system, a vein is a blood vessel that carries blood toward the heart. ... Grays Fig. ... Blood flows from the heart to arteries, which narrow into arterioles, and then narrow further still into capillaries. ... This page is about the condition called edema. ... The right lymphatic duct, about 1. ... In human anatomy, the thoracic duct is an important part of the lymphatic system — it is the largest lymphatic vessel in the body. ... The subclavian vein is a continuation of the axillary vein and runs from the outer border of the first rib to the medial border of anterior scalene muscle. ...


Function of the fatty acid transport system

Lymph vessels called lacteals are present in the lining of the gastrointestinal tract, predominantly in the small intestine. 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. 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. In anatomy, lymph vessels are thin walled, valved structures that carry lymph. ... A lacteal is a lymphatic capillary that absorbs dietary fats in the microvilli of the small intestine. ... Gut redirects here. ... In biology the small intestine is the part of the gastrointestinal tract (gut) between the stomach and the large intestine and comprises the duodenum, jejunum, and ileum. ... The portal vein is a major vein in the human body draining blood from the digestive system and its associated glands. ... The liver is the largest internal organ in the human body, and is an organ present in vertebrates and some other animals. ... In human anatomy, the thoracic duct is an important part of the lymphatic system — it is the largest lymphatic vessel in the body. ... In biology the small intestine is the part of the gastrointestinal tract (gut) between the stomach and the large intestine and comprises the duodenum, jejunum, and ileum. ... Chyle is a milky fluid (bodily fluid) consisting of lymph and emulsified fats, or free fatty acids (FFAs). ... The liver is the largest internal organ in the human body, and is an organ present in vertebrates and some other animals. ...


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. Elephantiasis (Greek ελεφαντίασις, from ελέφαντας, the elephant) is a disease that is characterized by the thickening of the skin and underlying tissues, especially in the legs and genitals. ... A parasitic disease is a disease caused or transmitted by a parasite. ... Lymphatic filariasis is parasitic infection of the lymphatic circulation which may result in the deforming disease known as elephantiasis. ...


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 lymphedema that has gone long untreated. While treatment can help a little, it is not reversible. Azskeptic 17:34, 10 July 2007 (UTC) Lymphedema, also spelled lymphoedema, also known as lymphatic obstruction, is a condition of localized fluid retention caused by a compromised lymphatic system. ...


Some common causes of swollen lymph nodes include staph infections, infectious mononucleosis and neoplasm, e.g. Hodgkin's and non-Hodgkin's lymphoma, and metastasis of cancerous cells via the lymphatic system. Binomial name Staphylococcus aureus Staphylococcus aureus (also known as golden staph) is a bacterium, frequently living on the skin or in the nose of a healthy person, that can cause illnesses ranging from minor skin infections (such as pimples, boils, and cellulitis) and abscesses, to life-threatening diseases such as... Neoplasia (literally: new growth) is sudden and abnormal growth in a tissue or organ. ... Non-Hodgkins lymphoma is a type of cancer. ... For the musical composition, see Metastasis (Xenakis composition). ...


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 mesoderm is one of the three germ layers in the early developing embryo, the other two layers being the ectoderm and the endoderm. ...


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. The cisterna chyli (or receptaculum chyli) is a dilated sac at the lower end of the thoracic duct into which the intestinal trunk and two lumbar lymphatic trunks flow. ...


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. Lymph nodes are components of the lymphatic system. ...


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. The spleen is an organ located in the abdomen, where it functions in the destruction of old red blood cells and holding a reservoir of blood. ... Thymus, see Thyme. ...


See also

Azskeptic 17:34, 10 July 2007 (UTC) Lymphedema, also spelled lymphoedema, also known as lymphatic obstruction, is a condition of localized fluid retention caused by a compromised lymphatic system. ... This article is about lymphoma in humans. ... There are very few or no other articles that link to this one. ... This article should appear in one or more categories. ...

References

External links

Wikimedia Commons has media related to:
Lymphatic system
The intestinal trunk receives the lymph from the stomach and intestine, from the pancreas and spleen, and from the lower and front part of the liver. ... The preaortic lymph nodes lie in front of the aorta, and may be divided into celiac, superior mesenteric, and inferior mesenteric groups, arranged around the origins of the corresponding arteries. ... The inferior mesenteric glands consist of: (a) small glands on the branches of the left colic and sigmoid arteries (b) a group in the sigmoid mesocolon, around the superior hemorrhoidal artery (c) a pararectal group in contact with the muscular coat of the rectum They drain the descending iliac and... In common usage, a human leg is the lower limb of the body, extending from the hip to the ankle, and including the thigh, the knee, and the cnemis. ... The deep inguinal lymph nodes are located medial to the femoral vein and under the cribriform fascia. ... The superficial inguinal lymph nodes form a chain immediately below the inguinal ligament. ... The popliteal lymph nodes, small in size and some six or seven in number, are imbedded in the fat contained in the popliteal fossa. ...

  Results from FactBites:
 
Spleen and Lymphatic System (1176 words)
One of the major lymphatic vessels is the thoracic duct, which begins near the lower part of the spine and collects lymph from the pelvis, abdomen, and lower chest.
The right lymphatic duct is the other major lymphatic vessel and collects lymph from the right side of the neck, chest, and arm, and empties into a large vein near the right side of the neck.
Lymphatic tissue is also scattered throughout the body in different major organs and in and around the gastrointestinal tract.
ScienceDaily: Metastasis (1401 words)
Glioma -- A glioma is a type of primary central nervous system (CNS) tumor that arises from glial cells.
Lymphatic system -- Lymph originates as blood plasma lost from the circulatory system, which leaks out into the surrounding tissues.
The lymphatic system collects this fluid by diffusion into lymph capillaries, and...
  More results at FactBites »

 
 

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