LYMPHATIC SYSTEM
INNATE(NON-SPECIFIC)
IMMUNITY
ADAPTATIVE (SPECIFIC)
IMMUNITY
ADULT NURSING
,1|P age
Lymphatic System
Function
• Tissue drainage: the lymphatic system conducts through the lymphatic ves-
sels the excess of fluid filtered out of the blood stream (capillaries) back into
the blood stream.
• Absorption in the small intestine: lymphatic system provides surface for the
absorption of fat- and fat-soluble substances such as vitamins through lacte-
als (lymphatic vessels) in the small intestine.
• Immunity which involves the production and maturation of lymphocytes (white
blood cells).
Structure of the lymphatic system
The lymphatic system consists of:
• Lymph
• Lymphatic vessels
• Lymphatic organs
Lymphatic organs include primary and secondary lymphatic organs.
Primary organs are where immunity cells are originated, where they proliferate, and
get mature. They consist of red bone marrow and thymus.
Secondary organs are where they get in contact with foreign agents and fight infec-
tions. These include Lymph nodes, spleen, and tonsils.
➢ Lymph
Is a clear watery fluid with similar composition to plasma and much less proteins. It
carries proteins that leak out of the blood vessels back into the blood stream. The
lymph transports large foreign agents such as pathogens, dead or live phagocytes,
malignant cells, worn out or old cells and cell debris from damaged tissues into the
lymph nodes to be filtered, destroyed, and ingested by phagocytes.
,2|P age
Lymph movement in lymphatic vessels results from the contraction of muscles of
larger lymph vessels, the contraction of muscles of adjacent large arteries and from
the change in thoracic pressure associated with respiratory cycle.
➢ Lymphatic vessels
Lymphatic capillaries have the same structure as blood capillaries which is a single
layer of endothelial cells.
Larger lymphatic vessels have the same wall structure as veins, which consists of an
inner lying of endothelial cells, a middle layer of smooth and elastic tissue and an
outer layer of fibrous tissue. They also contain valves to ensure the lymph flows in
one way towards the thorax. Those larger lymphatic vessels converge or join and
form 2 main larger lymphatic ducts which are thinner right lymphatic duct and wider
left lymphatic duct or thoracic duct. Those ducts are deep in the body, run right by
the vertebral column.
Right lymphatic duct
This duct is 1cm long. It connects to the right subclavian vein. It drains the upper
right quadrant of the body which include right half of the thorax, head and neck and
the right arm.
Left lymphatic duct
This duct is 40 cm long and opens into the left subclavian vein. It starts from the cis-
terna chyli which is a lymphatic channel located in front of the first two lumbar verte-
brae. It drains the remaining ¾ of the body which includes both legs, pelvic and ab-
dominal cavities, the left half of the thorax, head and neck, and the left arm.
, 3|P age
Lymphatic trunk and ducts (no date) available at https://philschatz.com/anatomy-book
Radical mastectomy consists of removing cancer cells with the underlying lym-
phatic vessels because cancer cells metastasise or migrate through the lym-
phatic nodes. This can result in swelling.
➢ Lacteals
are special lymphatic capillaries in the villi of the small intestine. Their function is to
absorb fats and fat-soluble nutrients and drain it into the left lymphatic duct, to the
left subclavian vein back into the blood stream then to the liver.
Water soluble nutrients are absorbed directly from the small intestines into the
blood stream and are carried by the hepatic portal vein into the liver
➢ Lymph nodes
Consist of an outer capsule of fibrous tissue which falls inwards into trabeculae.
Lymph nodes are made of reticular and lymphatic tissue. Reticular cells produce fi-
bres which provide internal structure of the nodes. Lymphatic cells include lympho-
cytes and macrophages. Each node has a helium which is a concave surface where