A system of tiny tubes called lymph vessels and lymph nodes in the human body which transports the liquid called lymph from the body tissues to the blood circulatory system is called lymphatic system.

1. LYMPHATIC SYSTEM
MS. SHAKUNTALA KADAM

2. • A system of tiny tubes called lymph vessels (or
lymphatics) and lymph nodes (or lymph glands) in
the human body which transports the liquid called
lymph from the body tissues to the blood circulatory
system is called lymphatic system.
• Some of the tissue fluid may be reasbsorbed into the
blood vessels, but most of it enters another set of
minute channels named lymph vessels where it is
called lymph.
• COMPOSITION OF LYMPH:
(a) Cellular part
Only leukocytes (mostly lymphocytes ) ( No blood
platelets)
(b) Non - cellular part.
• Water - 94%
• solids ( proteins, fats, carbohydrates, enzymes,
antibodies, etc) - 6%

3. FUNCTIONS OF LYMPH
• Nutritive: Supplies nutrition and oxygen to those parts where blood cannot reach.
• Drainage : It drains away excess tissue fluid and metabolites and returns proteins to the blood
from tissue spaces.
• Absorption : Fats from the intestine are absorbed through lymphaticcs ( lacteals located in the
intestinal villi)
• Defence : Lymphocytes and monocytes of the lymph function to defend the body. The lymphatics
also remove bacteria from the tissues.
• The lymph nodes tend to localize the infection and prevent it from spreading to the body as a
whole. The tonsils on the sides of the neck are also lymph glands.

4. • The spleen is a large lymphatic organ, about
the size of a clenched fist, raddish brown in
colour and situated in the abdomen behind
the stomach and above the left kidney.
FUNCTIONS
• It acts like a blood reservoir. In an emergency
such as haemorrahage, physical or emotional
stress, or in carbon monoxide poisoning, the
spleen releases the stored blood into the
blood stream.
• It produces lymphocytes.
• It destroys worn-out red blood cells ( sharing
this function with the liver).
• In an embryo it produces RBCs.

5. The lymphatic system consists of the following parts :
1. Lymph capilaries
2. larger lymph vessels
3. Lymph nodes ( or Lymph glands)
4. Lymph
• Lymph capillaries are tiny tubes which arsent in the
whole body ( just like blood capillaries)
• Lymph capillaries, differe from blood capillaries in two
ways: lymph capillaries are closed ended (the end of
lymph capillaries in the tissues of the body is closed),
and the pores in the walls of lymph capillaries are
bigger in size ( than that of blood capillaries).
• Since the ends of the lymph capillaries in the body
tissues.
• Pores in the walls of the lymph capillaries are
somewhat bigger, so even large protein molecules
present in the tissue fluid can enter into lymph
capillaries.( which could not pass into blood
capillaries).

6. • The lymph capillaries join to form larger lymph
vessels. The lymph vessels have lymph nodes (or
lymph glands) at intervals
• The lymph nodes contain special type of cells
called lymphocyes.
• Lymph nodes containing lymphocytes are involved
in the cleaning of lymph and protecting the body
from disease.
• The lymph vessels are connected to large veins of
the blood circulatory system.
• Lymph is a light yellow liquid. lymph is not red like
blood because it does not contain red blood cells.
• Lymph contains large protein molecules and
digested food ( which comes in it from the tissue
fluid between the cells.)
• It also contains germs from the cells and fragments
of dead cells.
• Lymph is another medium of circulation in the
human body. But lymph flows in the only one
direction.form body tissues to the heart .
• Lymph is derived form the tissue fluid which
remains outside the cells of the body, so it is also
called extracellular fluid.

7. • Lymph containing large protein molecules,
digested fat, germs and fragments of dead
cells from the tissue fluid around the body
cells seeps into the lymph capillaries present
throughout the body.
• From the lymph capillaries, lymph passes into
larger lymph vessels containing lymph nodes.
• In the lymph nodes, lymph is cleaned by
white blood cells called lymphocytes. These
white blood cells eat the germs and dead
cells, and also make antiboidies for protecting
the body form disease.
• The cleaned lymph containing large protein
molecules, digested fat and other useful
materials tranported by lymph vessels to the
large veins ( called subcalvian veins) which
run just beneath the collar bone.
• These veins carry the lymph to the heart. In
theis way, the ciruclation of lymph from the
body tissues to the heart is completed.