Slide 1
Hello, today I am going to talk about the lymphatic system, the impact of the disorders in the
lymphatic system and their corrective treatments and we are going to look at a case study of
a patient with a disorder related to it.
Slide 2
“The lymphatic system is a system that removes unwanted toxins and excess fluid from the
body tissues and returns it to the bloodstream (Cleveland Clinic)” (Cleveland Clinic, 2020). It is a
subsystem of the circulatory and immune system. The lymphatic system is a one direction,
open-ended network of vessels. It recovers about 3 litres of blood every day, more than half
of our total blood volume in our bodies.
Slide 3
The lymphatic system is made of the primary lymphoid organs, which involves the bone
marrow and the thymus, which produces lymphocytes and the secondary lymphoid organs
which includes the nodes, spleen and tonsils, all of the fights and prevents the germs from
affecting the body.
Slide 4
The red bone marrow produces lymphocytes from the immature hematopoietic progenitor
cells in the lymphoid organs. It is the main site of hematopoiesis and lymphopoiesis and
where B cells mature, both myeloid and lymphnoid lineage are produced from here. The
bone marrow is within the centre of the bones in the body and has a spongy structure.
Thymus has the shape of a bow tie and is flat, it is located above the heart, between the
lungs and below the sternum it is where where T-cell lymphocytes are produced and
matured, T-cells or T lymphocytes are white blood cells that helps fight infections and they
are produced before puberty.
Tonsils stop germs from entering the body and contain white blood cells that kill gems. They
are covered by mucosa and are oval shaped, found in the back of the throat.
Spleen “fights germs in the blood, controls the levels and filters it by removing old and/or
damaged red blood cells” (NHS). They are covered by pink mucosa, they are oval shaped and
are found in the back of the throat.
The lymphatic vessels can be found everywhere in the body except the CNS, teeth, bones
and the cartilages and they have no pumps. They are larger than the capillaries but most of
them are smaller than the veins. “They operate under very low pressure and have valves to
keep the lymph flowing in one direction” (Cleveland Clinic) and preventing backflow, smooth
muscles in the vessel walls help the fluid to keep moving through the vessels. “Valves are
found in the large lymph vessels and collecting vessels but they are not present in the
lymphatic capillaries” (Lumen).
The lymph nodes, which are also called lymph glands, are kidney shaped small that contain
defence cells called lymphocytes and macrophages. Lymphocytes are white blood cells that
are used to fight infections and are found and matured in the loose reticular connective
tissue that makes up a lot of the nodes and other lymphoid organs. They “attack and break
down bacteria, viruses, damaged cells or cancer cells” (Macmillan Cancer Support) , this prevents
harmful substances being fed back into our bloodstream. Macrophages are “a type of white
blood cell that ingests foreign material” (Shiel Jr.) , found in liver, spleen and connective
tissues.
Lymph nodes are basically checkpoints that monitor and cleanse the lymphatic fluid as it
passes through and carries the waste products in “the lymph fluid through larger lymph
, vessels up to the neck where the thoracic duct empties the lymph back into the blood
circulation” (Cancer Research UK). We have about 600-700 nodes throughout our bodies. The
main nodes are: Cervical nodes which are found in the back and sides of the neck, filters the
lymph that comes from the neck, scalp and head, axillary nodes which are found around the
armpit are responsible to drain fluids from the neck, breasts, upper arms and the underarm
area, popliteal nodes drains the lymphatic fluid from the superficial lymphatic vessels in the
legs and foot and are found in the fat contained in the knee pit, which is also called the
‘popliteal fossa’, the supratrochlear nodes are found around the medial epicondyle of the
humerus and drains the tissues from the arm and forearm, the abdominal nodes which are
found around the inferior vena cava and the abdominal aorta and the inguinal nodes which
are found in the groin area, drain the tissues from the groin to the feet.
Lacteals are found in the villi of the small intestine, they are lymphatic capillaries that absorb
lipids from the small intestine.
And the thoracic duct transports and drains lymph back into the bloodstream. It is a duct that
goes from the root of the neck to T12 which is the twelfth thoracic vertebrae. It is about 40
cm long and has a diameter of approximately 5 mm. It takes the lymph from the rest of the
body and dumps it into the subclavian vein.
Part B.P3, B.M2
Slide 5
Lymph is a fluid made of white blood cells that flows through the lymphatic system. It is
made up of lymphocytes, waste material from cells, pathogens and damaged cells, water
and excess interstitial tissue fluid. Plasma leaves blood vessels to deliver nutrients, oxygen
and hormones to the cells and becomes tissue fluid, which then absorbs cellular waste,
water and toxins. 90% of the fluid goes back to the blood circulation and the rest drains into
the lymph vessels, forming the lymph. The lymph protects our bodies from unknown
pathogens and "carries the waste products and the dead bacteria back into the circulatory
system, where other kidneys and liver remove them from the blood" (MacMillan Cancer Support,
2018).
Part B.P3, B.M2
Slide 6
The major functions of “the lymphatic system are formation and transportation of
lymphocytes, removal of intestinal fluid from tissues, maintenance of hydrostatic pressure
and absorption of fats from the digestive tract” (Sawtry Village Academy).
Part B.P3, B.M2
Slide 7
Lymphocytes increase in number by dividing in the thymus gland and in the lymph nodes.
The lymph capillaries are the smallest lymph vessels which run throughout the body
alongside the veins and the arteries. The capillaries have very thin and permeable walls.
There are some lymph vessels that contain smooth muscles and/or skeletal muscles so that
it contracts to move the lymph fluid. They also contain semilunar valves that prevent
backflow, so that the fluid does not go in the wrong direction. Skeletal muscle contracts so
that lymph vessels get compressed and move the lymph fluid to the subclavian veins that
are situated in the lower neck region. The lymph capillaries join together to form larger
vessels similar to veins but with more semilunar valves and thinner walls. And the lymph
vessels join together to form the thoracic duct and the right lymph duct. The lymph fluid from
these two ducts drains into the blood vessels of the lower neck region.
