Posted by jayaram in Introduction
Lymphatic system is a closed system of lymph channels or lymph vessels through which lymph flows. It is a one-way system and allows the lymph flow from tissue spaces towards the blood.
Origin of lymphatic system
The lymphatic system arises from tissue spaces as a meshwork of delicate vessels. These vessels are called capillaries. The lymph capillaries start from tissue spaces as enlarged blind-ended terminals called capillary bulbs. These bulbs contain valves, which allow flow of lymph in one direction towards blood. There are some muscle fibers around these bulbs. These muscle fibers cause contraction of bulbs so that, lymph can move through the vessels.
Endothelial cells line the lymph capillaries. The capillaries unite to form large lymphatic vessels. The lymphatic vessels become larger and larger due to the joining of many tributaries with them along their course.
The structure of lymph capillaries is slightly different from that of blood capillaries. The lymph capillaries are more porous and the cells lie overlapping on one another. This allows the fluid to move into the capillaries and not to outside.
Drainage of lymphatic system
The larger lymph vessels ultimately form right lymphatic duct and thoracic duct. The right lymphatic duct opens into right subclavian vein and the thoracic duct opens into left subclavian vein.
Lymph nodes
Lymph nodes are small glandular structures located in the course of lymph vessels. The lymph nodes are also called lymph glands or lymphatic nodes.
Lymphatic vessels to lymph node
The lymph node receives lymph by one or two lymphatic vessels called afferent vessels. After passing through the small channels arising from the afferent vessels. Lymph circulates through cortex, Para cortex and medulla of the node. From medulla, the lymph leaves the node through one or two efferent vessels.
Distribution of lymph nodes
The lymph nodes are present along the course of lymphatic vessels in elbow, axilla, knee and groin. The lymph nodes are also present in certain points in abdomen, thorax and neck pain where many lymph vessels join.