How many lymphatic ducts

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Learn more about our commitment to Global Medical Knowledge. This site complies with the HONcode standard for trustworthy health information: verify here. Common Health Topics. Disorders of the lymphatic system. Lymphatic Disorders.

Test your knowledge. Swelling is a condition caused by excess fluid in the tissues. The fluid involved in swelling is primarily water. Swelling may occur in one or several parts of the body, often the feet and lower legs.

Swelling that occurs throughout the body has different causes than swelling in a single limb or part of a limb. Which of the following is a frequent cause of swelling in a single limb or part of a limb? Lymph Ducts Two lymph ducts receive lymph from the lymph trunks. The thoracic lymph duct, the largest lymph vessel in the body, takes lymph from the lower and left halves of the body. Because the thoracic lymph duct drains the intestinal lymph trunks, it carries a mixture of lymph and emulsified fatty acids called chyle back to the bloodstream.

The right lymphatic duct receives lymph from the right and upper halves of the body, including the right sides of the jugular, bronchomediastinal, and subclavian lymph trunks. Authored by : Boundless. Provided by : Boundless. Provided by : Wikipedia. Located at : en.

Provided by : Wiktionary. Provided by : Wikimedia. As the interstitial fluid begins to accumulate, it is picked up and removed by tiny lymphatic vessels and returned to the blood. As soon as the interstitial fluid enters the lymph capillaries , it is called lymph.

Returning the fluid to the blood prevents edema and helps to maintain normal blood volume and pressure. Lymphatic vessels, unlike blood vessels, only carry fluid away from the tissues. The smallest lymphatic vessels are the lymph capillaries, which begin in the tissue spaces as blind-ended sacs. They grow successively larger as they increase their distance from the capillaries and reduce their distance from the heart. As they move towards the heart, lymphatic collecting vessels pass through thousands of lymph nodes which filter the lymph.

The collecting vessels are divided into sections by valves. There are two lymphatic ducts also called lymphatic trunks , ductus thoracicus left lymphatic, or thoracic duct and ductus lymphaticus dexter right lymphatic duct , respectively located in the left and right thoracic chest region. The two ducts connect the large lymphatic collecting vessels to the blood circulation via the subclavian veins which pump blood into the heart.

The ductus thoracicus connects to the left subclavian vein, while the ductus lymphaticus dexter connects to the right subclavian vein. The junction where the lymphatic ducts and subclavian veins meet is the only direct connection between the blood and lymph circulatory systems, and thus the only point where lymph can enter the blood circulation.

Thousands of lymph nodes occur in clusters along the lymphatic vessels. They are particularly abundant in the lower abdomen, neck and armpits. Each lymph node connects to several afferent lymphatic vessels on one side known as the cortex and lymph enters the node through these connections.

Each node also connects to a smaller number of efferent lymphatic vessels on the other side known as the hilus and lymph exits the node through these connections. Lymph nodes can be separated into a fibrous outer capsule and an inner cortex of soft tissue.

The cortex is segmented by strands called trabeculae, which are extensions of the fibrous capsule. Lymph enters and travels through the lymph node cortex.

The segments of the lymph node cortex support a dynamic changing population of lymphocytes. The lymphatic system as a whole supports an abundance of lymphocytes, with a collective weight of 1 kg in a 70 kg body. Each node also contains static unchanging collections of macrophages. Structures called follicles within the lymph nodes support static populations of B-lymphocytes antibody-producing lymphocytes.

Lymphoid tissue, also referred to as lymphoid nodules, is tissue that is dominated by the lymphocytes. A lymphoid nodule is usually about a millimetre in diameter, but as there is no capsule surrounding it, it is often hard to measure.

Examples of these nodules include the gut-associated lymphatic tissue GALT cells as well as the tonsils. The lining of other hollow organs also contain patches of lymphoid tissue. Lymphoid organs are characterised by abundant lymphocytes and connective structural tissues. In addition to the lymph nodes they include:. While each of these organs and tissues fulfils protective immune functions which are related to the lymphatic system, the lymph nodes are unique amongst the lymphoid organs because they are the only organs with lymph filtering functions.

The spleen is a blood-rich organ and the largest of the lymphoid organs. It is usually purple in colour, and located in the upper-left section of the abdomen. The spleen is surrounded by the lining of the abdominal cavity on all sides except at the hilum, where the splenic artery and vein are located.

The spleen lies behind to the stomach and in front of the diaphragm, near the left kidney. It is covered by a fibrous capsule which is thickest at the hilum, where the splenic artery and vein connect and transport blood into and out of the spleen. The spleen is composed of areas of red pulp and white pulp. Most of the red pulp consists of loose tissues and blood capillaries. The splenic white pulp is made of two types of lymphocytes; T lymphocyte infection detecting and B lymphocyte antibody producing.

The thymus is a lymphoid organ located in the lower section of the throat, overlying the heart. It receives a rich supply of arterial blood from the large arteries which connect to it.

The veins which drain blood from the thymus connect to larger veins in the chest area. The thymus is divided into two lobes which each have an outer cortex and an inner medulla. The cortex sections contain T lymphocyte stem cells, while the medulla contains mature T lymphocytes which have migrated from the cortex. The thymus also contains hormone producing cells. The lymphatic system commences development during embryogenesis the period from 4—8 weeks after fertilisation, in which the fertilised egg is called an embryo.

First, several tiny sacs called lymph sacs form. These continue to grow to form lymphatic capillaries, vessels and nodes. The vessels and clusters of nodes are visible by the 5 th week of embryo development the 7 th week of pregnancy which begins 2 weeks before fertilisation occurs. However, while the foetus remains in the womb the lymphatic system remains underdeveloped and does not function.

It is not until after childbirth when lymphocytes rapidly populate lymph nodes and immune functions commence. Before entering the lymphatic system, lymph is called interstitial fluid and consists mainly of a fluid called hyaluronan. This interstitial fluid plays an important role in giving shape and structure to the body organs, and in order to give each organ or body part the correct structure, the volume of interstitial fluid must remain constant.

If interstitial fluid accumulates, swelling occurs and the shape and structure of the organ or body part changes. So although the lymphatic system is constantly absorbing interstitial fluid from the interstitial spaces, there is always a constant volume of interstitial fluid in a given interstitial space except for example in times of inflammation and swelling.

The lymphatic system only absorbs fluid when new fluid is leaked into the space to replace that absorbed into the lymphatic system. Absorption of lymph into the lymphatic vessels plays an important role in maintaining the correct amount of fluid in the interstitial spaces to ensure that swelling does not occur. A considerable quantity of fluid leaks from the blood circulation each day. While the majority of leaked blood is reabsorbed by the blood vessels, up to 3 L per day remains in the spaces between tissues and becomes part of the interstitial fluid.

Unless this fluid is absorbed by the lymphatic system, too much fluid will accumulate in the interstitial spaces and swelling will occur. Once an organ or body part is swollen, the process by which lymph and blood exchange their component parts becomes impaired.

This stops lymph and blood exchanging potentially dangerous components such as antigens e. It enables the dangerous substance to be localised kept within a particular area. While swelling is often a necessary immune response which prevents the spread of an antigen, in some cases the immune system functions irregularly, as swelling can occur when it is not needed to protect the body.

The key function of lymph is to transport blood components back to the blood stream and maintain the correct volume of blood circulation. Interstitial fluid is fluid which has leaked from the blood circulation and contains blood cells and proteins which are essential components of blood.

Once absorbed into the lymphatic system, the interstitial fluid becomes known as lymph and travels through the lymphatic vessels to the subclavian veins where it re-enters the blood circulation and maintains blood volume.