lymphatic

Examples of lymphatic in the following topics:

• Structure of the Lymphatic System

  • The lymphatic system consists of lymphatic vessels and associated lymphoid organs.
  • The structure of the lymphatic system facilitates these general roles.
  • The lymphatic vessels are the lymphatic system equivalent to the blood vessels of the circulatory system and drains fluid from the circulatory system.
  • Lymphatic organs are the site of many important functions for the immune system.
  • Describe how the lymphatic system consists of lymphatic vessels and associated lymphoid organs

• Lymphatic Tissue Development

  • Lymphatic tissue development begins by the end of the fifth week of embryonic development.
  • Lymphatic tissues begin to develop by the end of the fifth week of embryonic development.
  • Lymphatic vessels develop from lymph sacs that arise from developing veins, which are derived from mesoderm.
  • 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.

• Distribution of Lymphatic Vessels

  • The lymphatic system comprises a network of conduits called lymphatic vessels that carry lymph unidirectionally towards the heart.
  • The lymphatic system is a circulatory system for lymphatic fluid, comprising a network of conduits called lymphatic vessels that carry a lymphatic fluid, in one direction towards the heart.
  • Lymphatic vessels are most densely distributed near lymph nodes.
  • Afferent lymphatic vessels: the lymph vessels that flow into a lymph node.
  • Efferent lymphatic vessels: the lymph vessels that flow out of a lymph node.

• Lymph Trunks and Ducts

  • After filtration by the lymph nodes, efferent lymphatic vessels take lymph to the end of the lymphatic system.
  • The final goal of the lymphatic system is to recirculate lymph fluid back into the plasma of the bloodstream.
  • There are two specialized lymphatic structures at the end of the lymphatic system, which are called the lymph trunks and ducts.
  • Lymphatic trunks then drain lymph fluid into the lymph ducts, which are the final part of the lymphatic system.
  • Reaching this point marks the end of lymph fluid's journey through the lymphatic system.

• Lymphatic Capillaries

  • Lymphatic circulation begins in the smallest type of lymph vessels, which are the lymph capillaries.
  • Lymphatic capillaries are primarily made out of an endothelium layer that sits on a permeable basement membrane.
  • They extend out from the lymphatic capillary, attaching the endothelium to fibroblast cells in the connective tissue.
  • Unlike larger lymphatic vessels, lymphatic capillaries do not contain smooth muscle, nor do they have a well developed adventita, only small elastic filaments that perform a similar function to adventitia.
  • The other function of the lymphatic capillaries is to bring lymph further into the lymphatic vessels.

• Functions of the Lymphatic System

  • The lymphatic system plays a prominent role in immune function, fatty acid absorption, and removal of interstitial fluid from tissues.
  • The lymphatic system is the site of many key immune system functions.
  • One of the main functions of the lymphatic system is to drain the excess interstitial fluid that accumulates.
  • The lymphatic system is a blunt-ended linear flow system, in which tissue fluids, cells, and large extracellular molecules, collectively called lymph, are drained into the initial lymphatic capillary vessels that begin at the interstitial spaces of tissues and organs; are transported to thicker collecting lymphatics, which are embedded with multiple lymph nodes; and are eventually returned to the blood circulation through the left and right subclavian veins, and into the vena cava.
  • The lymphatic system also facilitates fatty acid absorption from the digestive system.

• Lymphatic Vessel Structure

  • The general structure of lymphatic vessels are similar to that of blood vessels.
  • This is largely because blood vessels and lymphatic vessels are the two types of vessels in the body.
  • The smallest vessels, such as the lymphatic capillaries even lack the outer adventitia altogether.
  • Valves are found in larger lymph vessels and collecting vessels and are absent in the lymphatic capillaries.
  • A lymphagion is the term for the space between two semilunar valves in a lymphatic vessel, and represents a functional unit of the lymphatic system.

• Lymphoid Tissue

  • Lymphatic tissues begin to develop by the end of the fifth week of embryonic development.
  • Lymphatic vessels develop from lymph sacs that arise from developing veins, which are derived from mesoderm, the inner tissue layer of the embryo.
  • Development of lymphatic tissue starts when venous endothelial tissues differentiate into the lymphatic endothelial tissues.
  • The lymphatic endothelial cells proliferate into sacs that eventually become lymph nodes, with the afferent and efferent vessels that flow out from the lymph nodes.
  • Smaller lymph vessels and lymphatic capillaries develop after that until the lymphatic system is completed at the closed end of every lymphatic capillary.

• Metastasis Through Lymphatic Vessels

  • Some cancer cells acquire the ability to penetrate the walls of lymphatic and/or blood vessels, after which they are able to circulate through the bloodstream (circulating tumor cells) to other sites and tissues in the body.
  • This process is known as a lymphatic or hematogeneous spread.
  • Metastasis is a complex series of steps in which cancer cells leave the original tumor site and migrate to other parts of the body via the bloodstream or the lymphatic system.
  • By degrading the ECM, which acts as a barrier to adjoining tissue, cancer cells are able to breach the ECM and enter the lymphatic system.
  • Lymphatic spread: Invasion into the lymphatic system allows the transport of tumor cells to regional and distant lymph nodes and, ultimately, to other parts of the body.

• Submucosa

  • The submucosa is a dense irregular layer of connective tissue with large blood vessels, lymphatics, and nerves that supports the mucosa.
  • The submucosa consists of a dense irregular layer of connective tissue with large blood vessels, lymphatics, and nerves branching into the mucosa and muscularis externa.
  • Blood vessels, lymphatic vessels, and nerves (all supplying the mucosa) will run through here.