UNIT 8: Lymphatic system
What is the lymphatic system?
The lymphatic system is an intricate network of veins,
organs, lymphatic nodules, mucous membranes, bone
marrow, and organs that carry fluids and contain
specialised lymphatic fluid. These work together to
assist the body in eliminating toxins, waste, and other
undesirable items. In order to battle infections and other
illnesses, throughout the body, the lymphatic system's
main function is to transport lymph, a fluid that includes
white blood cells that fight infections.
Functions of the lymphatic system:
● Transport of lymph
Thin-walled, valved structures called lymphatic vessels
transport lymph. the lymphatic system as a whole. The
cardiovascular system works better when lymph
vessels are present. Lymph capillaries, the smallest
lymph vessels, are found next to the body's arteries and
veins. The lymph is returned to the systemic circulation
through lymph ducts that drain it into a subclavian vein.
Certain lymph veins have smooth muscle walls, and this
muscle contracts on a regular basis to convey the fluid.
Lymph is driven into the subclavian veins in the lower
neck region as a result of the compression of lymphatic
vessels brought on by skeletal muscle contraction.
● Interstitial fluid removal from tissues
The fluid between cells within cells in tissues is called
interstitial fluid. Also called interstitial fluid. The source
of the substance is plasma, which is discharged from
the capillaries at the end of the arteries. It cleanses cells and promotes the exchange of
substances. Carbon dioxide, other waste products, and certain proteins flow from the
interstitial fluid into the cells, and oxygen and nutrients diffuse from the interstitial fluid into
the cells.
● Maintenance of hydrostatic pressure
There are two distinct pressure categories. inertial pressure, the force that a fluid (like water)
is transmitting or applying when it is at rest. Osmotic pressure and heartbeat contraction are
to blame for this. a differential in solute concentration between liquids divided by a
semipermeable barrier that results in a hydrostatic pressure. Hydrostatic pressure is
maintained when lymph flows into the neck vessels and increases blood volume (blood
pressure is produced by the fluid in the blood vessels).
● Blood filtration
Foreign substances as well as other viruses and bacteria are filtered out by the spleen. Old
red blood cells that can no longer serve their purpose are removed from the circulatory
,system by its main organ, the spleen. It is also an important component of the immune
system as it produces the white blood cells needed to fight infections and make antibodies.
The spleen is essential for many bodily processes, but not for life, and it is possible to
survive without a spleen. Red blood cells can be removed.
● Immune cell transport
Cells involved in immune system activity are transported through the lymphatic system. Most
notably, the migration of highly specialised leukocytes called lymphocytes and
antigen-presenting cells to local lymph nodes where the immune system contacts
pathogens. The lymphatic system is essential for immune cell migration, but because of its
migratory capacity, cancer can spread through it. Tumours can spread to distant parts of the
body, primarily through the lymphatic circulation, and are difficult to stop. On the tissue,
lymphatic capillaries are penetrated by extra tissue fluid that has escaped from capillaries.
Large protein molecules in the tissue fluid can also enter the lymphatic capillaries because
the small holes in the lymphatic capillary walls are bigger than those in capillary walls. The
tissue is then free of these protein molecules. They have an osmotic impact that hinders the
clearance of tissue fluid and results in swelling if they don't go out of hand.
What are lymphocytes?
● Most vertebrates have lymphocytes as a type of white blood cell in their immune
system T cells, and B cells are examples of lymphocytes. They are the major cell
type of lymphocytes, hence the term lymphocytes.
What do lymphocytes do?
● B cells and T cells are two major subtypes of lymphocytes. Antibodies produced by B
cells are used to fight foreign bacteria, viruses, and toxins. The body's own cells that
are infected with viruses or become malignant are destroyed by T cells.
How are they transported?
● Lymphocytes exit the node through afferent tubes and are carried by lymph to other
areas of the body, where they carry out adaptive immune response activity
● Lymph vessels
Location
Except for the bone marrow, the brain, and tissues lacking blood vessels like the epidermis,
every portion of the body has lymph capillaries.
Structure, importance and function in the body
The thin-walled and valved lymphatic vessels that carry lymph do so. Among other things, it
facilitates plasma circulation in the cardiovascular system and hosts a few immune system
functions. Numerous lymphatic vessels spread out extensively across the body make up the
lymphatic system. Lymphatic capillaries, which are locations where lymph fluid is gathered,
are present in most human tissues, particularly connective tissue.
Abnormal function
A persistent illness called lymphedema results in swelling of the body's tissues. Although it
can affect any area of the body, lymphedema commonly occurs in the arms and legs. Fluid
accumulates in the limbs as a result of clogged or injured lymph veins, which prevent lymph
from flowing through the body normally. You may need help from physical and occupational
therapists, depending on your diagnosis. Decongestive lymphatic therapy is advised for
lymphoedema patients. Although DLT cannot treat lymphoedema, it may help manage the
, symptoms with the use of compression bandages, frequent exercise, skin care, and
specialised massage methods.
● Lymph nodes
Location
Lymph nodes are tiny, bean-shaped organs that produce and store blood cells that help the
body fight disease and infection. The organs that contain lymphocytes, lymphatic fluid, and
cell detritus are known as lymph nodes or lymph glands. The body's neck, armpits,
abdomen, and groynes are just a few places where lymph nodes may be located.
Structure, importance and function in the body
Separated macrophages eat germs, cancer cells, and other foreign material in the lymph
nodes. Lymphocytes and some antibodies are picked up by the fluid as it exits the nodes.
Antigenic material that is travelling through the lymph and blood is captured by dendritic cells
in the lymph nodes and delivered to the local lymphocytes. T- and B-cell development was
the outcome of this. These antigens on their surfaces enable them to initiate an immune
response against intruders.
Abnormal function
As a result of bacterial and viral illness, lymph nodes may enlarge. They typically have
armpit and groyne swelling. Leukaemia and lymphoma are two malignancies that can be
brought on by swollen lymph nodes. Once the illness has cleared up, swollen lymph nodes
often go away. Antibiotics and antivirals need to be used if not. Taking over-the-counter pain
relievers like acetaminophen or ibuprofen, putting a warm wet compress to the afflicted
region, consuming lots of fluids like water and fresh juices, and getting enough rest to aid in
the body's recovery from the disease are further remedies.
● Lymph Valves
Location
Found in larger lymph veins and collecting channels.
Structure, importance and function in the body
In order to prevent lymphatic fluid from flowing backward, lymphatic veins have one-way
valves, semilunar structures joined to opposing sides of the lymphatic endothelium. The
larger, smooth-muscle-and-valve-equipped contractile lymphatics take the lymph from the
lymph capillaries. The lymphatic system doesn't have a pumping organ to move lymph
through its network of channels, unlike the blood circulatory system. Lymph is forced from
one node to the next by tiny one-way valves. Despite low pressure, lymph movement still
happens because of compression brought on by the adjacent skeletal muscle contraction
and artery pulse.
Abnormal function
Valves ensure that lymph is transported efficiently from the lymphatic capillaries to the lymph
node by preventing the backflow of fluid and causing it to flow forward rather than backward.
Lymphedema and fibrosis may result from the movement of lymph in the opposite direction.
● Thymus gland
