The Lymphatic System Back to Top The lymphatic system is composed of lymph vessels, lymph nodes, and organs.
A lymph Lymphatic system and immunity showing afferent and efferent lymphatic vessels A lymph node is an organized collection of lymphoid tissue, through which the lymph passes on its way back to the blood.
Lymph nodes are located at intervals along the lymphatic system. Several afferent lymph vessels bring in lymph, which percolates through the substance of the lymph node, and is then drained out by an efferent lymph vessel.
There are between five and six hundred lymph nodes in the human body, many of which are grouped in clusters in different regions as in the underarm and abdominal areas. Lymph node clusters are commonly found at the base of limbs groin, armpits and in the neck, where lymph is collected from regions of the body likely to sustain pathogen contamination from injuries.
The substance of a lymph node consists of lymphoid follicles in an outer portion called the cortex.
The inner portion of the node is called the medullawhich is surrounded by the cortex on all sides except for a portion known as the hilum.
The hilum presents as a depression on the surface of the lymph node, causing the otherwise spherical lymph node to be bean-shaped or ovoid.
The efferent lymph vessel directly emerges from the lymph node at the hilum. The arteries and veins supplying the lymph node with blood enter and exit through the hilum. The region of the lymph node called the paracortex immediately surrounds the medulla.
Unlike the cortex, which has mostly immature T cells, or thymocytesthe paracortex has a mixture of immature and mature T cells. Lymphocytes enter the lymph nodes through specialised high endothelial venules found in the paracortex.
A lymph follicle is a dense collection of lymphocytes, the number, size and configuration of which change in accordance with the functional state of the lymph node. For example, the follicles expand significantly when encountering a foreign antigen.
The selection of B cellsor B lymphocytes, occurs in the germinal centre of the lymph nodes.
Lymph nodes are particularly numerous in the mediastinum in the chest, neck, pelvis, axillainguinal regionand in association with the blood vessels of the intestines.
It consists of connective tissue formed of reticular fiberswith various types of leukocyteswhite blood cellsmostly lymphocytes enmeshed in it, through which the lymph passes. Lymphoid tissue can either be structurally well organized as lymph nodes or may consist of loosely organized lymphoid follicles known as the mucosa-associated lymphoid tissue.
The central nervous system also has lymphatic vessels, as discovered by the University of Virginia Researchers. The search for T-cell gateways into and out of the meninges uncovered functional meningeal lymphatic vessels lining the dural sinusesanatomically integrated into the membrane surrounding the brain.
Lymphatic vessel Lymph capillaries in the tissue spaces The lymphatic vesselsalso called lymph vessels, conduct lymph between different parts of the body. They include the tubular vessels of the lymph capillariesand the larger collecting vessels—the right lymphatic duct and the thoracic duct the left lymphatic duct.
The lymph capillaries are mainly responsible for the absorption of interstitial fluid from the tissues, while lymph vessels propel the absorbed fluid forward into the larger collecting ducts, where it ultimately returns to the bloodstream via one of the subclavian veins.
These vessels are also called the lymphatic channels or simply lymphatics.
Learn about the lymphatic system and innate and adaptive immunity in this guest blog post by Professor Nilson of the University of British Columbia. The immune and lymphatic systems are two closely related organ systems that share several organs and physiological functions. The immune system is our body’s defense system against infectious pathogenic viruses, bacteria, and fungi as well as parasitic animals and protists. May 31, · This is part 1 of the VHSG Advanced Biology course presentation on the lymphatic system. Self Healing & Cleansing Lymphatic Lymphatic System: Introduction To .
Its network of capillaries and collecting lymphatic vessels work to efficiently drain and transport extravasated fluid, along with proteins and antigens, back to the circulatory system.
Numerous intraluminal valves in the vessels ensure a unidirectional flow of lymph without reflux. The collecting lymphatics, however, act to propel the lymph by the combined actions of the intraluminal valves and lymphatic muscle cells.The lymphatic system is part of the vascular system and an important part of the immune system, comprising a large network of lymphatic vessels that carry a clear fluid called lymph (from Latin, lympha meaning "water") directionally towards the heart.
The lymphatic system is composed of lymph vessels, lymph nodes, and organs. The functions of this system include the absorbtion of excess fluid and its return to the blood stream, absorption of fat (in the villi of the small intestine) and the immune system function.
DeWitt Structure & Function of the Body Chapter 13 The Lymphatic System and Immunity study guide by swargo13 includes 42 questions covering vocabulary, terms and more. Quizlet flashcards, activities and games help you improve your grades. DeWitt Structure & Function of the Body Chapter 13 The Lymphatic System and Immunity study guide by swargo13 includes 42 questions covering vocabulary, terms and more.
Quizlet flashcards, activities and games help you improve your grades. The lymphatic system is a network of tissues and organs that help rid the body of toxins, waste and other unwanted materials.
The primary function of the lymphatic system is to transport lymph, a. Nov 01, · The lymphatic system is a subsystem of the circulatory system in the vertebrate body that consists of a complex network of vessels, tissues, and organs.
It helps maintain fluid balance in the body by collecting excess fluid and particulate matter from tissues and depositing them in the bloodstream.