The Lymphatic System

Brief Account:

1. The lymphatic system consists of: Lymphatic capillaries, lymphatic vessels,lymph nodes, thymus gland, tonsils and spleen.

2.It plays 2 roles:
in Circulatory system
in Immune system.


3. Before you continue further with the system, you should be able to explain HOW lymph is formed! (lymph is actually a COLORLESS body fluid similar to plasma but has no erythrocytes, platelets and large proteins!!)

4. When you wanna explain how LYMPH is formed, you have to relate it with the formation of INTERSTITIAL FLUID..

5. The story or the sequence of event of How interstitial fluid is formed has been asked in SPM Paper 2...and it could be repeated because there is an interesting event occured there...

6. Question such as
Where is lymph derived from?
What are the main differences between blood and lymph?
Explain what is the importance of the interstitial fluid?
Explain how lymph is returned to the circulatory system.



7. The lymph has to be returned to the blood circulatory system to maintain the volume of the blood.

8. The movement of the lymph in the lymphatic system is caused by the difference of pressure mainly due to the contraction and relaxation of the skeletal muscles..(Bcoz lymphatic system do not have organ such as heart to pump!!)

9. Please take note of the paths in which lymph flows: lymphatic capillary--lymphatic vessel--lymph NODES--Thoracic duct //Right lymphatic duct--Left subclavian vein//right subclavian vein-- Heart --to join Blood circulatory system...
...Thats the reason why they said Lymphatic system COMPLEMENT blood circulatory system!!.


10..and Now..the lymph nodes..



A rounded mass of lymphatic tissue that is surrounded by a capsule of connective tissue.
Lymph nodes filter lymph (lymphatic fluid), and they store lymphocytes (white blood cells).
They are located along lymphatic vessels. Also called lymph gland.

A lymph node is a small bean-shaped organ of the immune system, distributed widely throughout the body and linked by lymphatic vessels.
Lymph nodes are found all through the body,
and act as filters or traps for foreign particles.
They contain white blood cells that use oxygen to process.
Thus they are important in the proper functioning of the immune system.

Lymph nodes also have clinical significance.
They become inflamed or enlarged in various conditions, which may range from trivial, such as a throat infection, to life-threatening such as cancers. In the latter, the condition of lymph nodes is so significant that it is used for cancer staging, which decides the treatment to be employed, and for determining the prognosis.

They may become enlarged due to a tumor or infection.
Lymphocytes, also known as white blood cells are located within lymph nodes.

The spleen and tonsils are large lymphoid organs that serve similar functions to lymph nodes, though the spleen filters blood cells rather than lymph.

..The question may ask you: Explain the function of lymph nodes:
1. filtering the pathogens
2. producing lymphocytes.
...and you may elaborate it depending on the marks allocated!