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LYMPHATIC SYSTEM LYMPHATIC SYSTEM

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LYMPHATIC SYSTEM LYMPHATIC SYSTEM Powered By Docstoc
					LYMPHATIC SYSTEM
 DR. NAWAL FOUAD
It is a system which returns the lymph to
   the blood stream
The lymph: is a clear colorless fluid which
   is formed at the tissue spaces.
It is composed of:
1-Blood plasma which is not taken up by
   the venous capillaries.
2- Proteins from the tissues
3- Lymphocytes
The lymphatic system is composed of
A- Lymphatic tissue :
Is a type of connective tissue that
contains large numbers of
lymphocytes.
It is classified into:
a- Lympatic aggregations
b- Lymph nodes.
  a-Lympatic aggregations: It is found
    in the following organs or
    structures:
Thymus.
Spleen.
Lymphatic nodules in close relation
to epithelium of the alimentary
canal e.g., tonsils, appendix,
Peyer’s patches of the ileum.
  b-Lymph nodes:
These are localised bean like collections of
lymphoid tissue which interrupt the course of
the lymphatics. They are present singly or in
groups in specific locations in the body.

Functions of lymph nodes:
Production of antibodies by the lymphocytes.
They pick up bacteria and antigens (by their
phagocytic cells) preventing them from
reaching the blood i.e., they act as filters
B- Lymphatic vessels:
 The lymphatic vessels lie either superficial to
deep fascia (superficial vessels) or deep to
deep fascia (deep vessels). The latter usually
follow the blood vessels. The superficial and
deep lymphatic vessels always communicate.
They assist the cardiovascular system in
removal of tissue fluid from the tissue spaces
of the body. The tissue fluid once it enters a
lymphatic vessel is known as lymph.
 The lymphatic system is essentially a
  drainage system not a circulatory one.
  The lymph is drained from the tissues by
  the lymph capillaries which are larger
  than the blood capillaries ( to carry large
  protein molecules).
The lymph capillaries unite to form small
lymph vessels, which are collected to
form large lymph vessels that possess
numerous valves giving them a beaded
appearance.
The lymphatic vessels return the
  tissue fluid (lymph) to the blood
  after filtering it as it passes through
  at least one lymph node.
 The lymph vessels that carry lymph
to a lymph node are known as
afferent vessels, those that
transport it away from the node are
efferent vessels.
The lymph reaches the blood stream at
  the root of the neck by large lymph
  vessels ,
in the right side, there is the right
  lymphatic duct.
and in the left side, there is the thoracic
duct.
These ducts open into the veins of the
root of the neck ,so all the lymph
pours into the blood stream.
Sites without             Sites rich with
  lymphatics:               lymphatics:
• 1-The central           1-Dermis.
  nervous system.
                          2- Mucous
• 2- Bone marrow.
                            membranes.
• 3- Spleen.
• 4- Avascular            3- Serous
  structures                membranes.
  (epidermis, articular   4- Glands.
  cartilages).
Clinical notes:
Obstruction of the lymphatics of a certain
  part leads to its oedema, e.g. in
  elephantiasis.
The lymph nodes may become enlarged
  and painful if they receive infected
  lymph.
Certain types of cancer prefer to send
  secondaries and spread via the
  lymphatics. As a result, the draining
  lymph nodes enlarge and form masses.

				
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posted:1/15/2012
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