Lymphatic System and Immunity
Lymphatic System
Lymphatic System
• High hydrostatic pressure in the arterioles and capillaries at the arterial part of the
circulation leads to move plasma fluid from the capillaries to the interstitial tissue. Some of
this fluid returns to the bloodstream at the venous site while the remainder returns to the
circulation through vessels of a separate system that is called the lymphatic system.
• The fluid that enters the lymphatic vessels is called lymph.
• The lymphatic system is a part of circulatory system. The main function of it is to return
fluids escaped from capillaries to the circulation and also play an important role in defense
and immunity.
, Functions of the Lymphatic System
1. Tissue drainage: every day around 21 liters of fluid of plasma, carrying dissolved substances
and some plasma protein escape from the arterial end of the capillaries and into the tissues.
Most of this fluid is returned directly to the bloodstream via the capillary at its venous end,
but the excess, about 3-4 liters of fluid is drained away by the lymphatic vessels.
2. Returns the excess protein to the circulation.
3. Remove waste products and toxins.
4. Fat absorption: fat and fat soluble materials (e.g. fat soluble vitamin) are absorbed into the
central lacteals.
5. Essential to the immune system.
Components of Lymphatic System
I. Lymph
II. Lymph vessels
III. Lymph nodes
IV. Lymph organs
V. Diffuse lymphoid tissue
, I. The Lymph
• Lymph is a clear watery fluid, similar in composition to plasma, with exception of plasma
proteins (lymph contains small amounts of proteins).
• Lymph contains cells mainly lymphocytes, large molecules of fat (chylomicrons) that are
absorbed from the intestines enter lymph vessels.
Blood circulation, lymphatic circulation, and innervation of the small intestine. The smooth muscle
system for contracting the villi is illustrated in the villus on the right.
Lymphatic System
Lymphatic System
• High hydrostatic pressure in the arterioles and capillaries at the arterial part of the
circulation leads to move plasma fluid from the capillaries to the interstitial tissue. Some of
this fluid returns to the bloodstream at the venous site while the remainder returns to the
circulation through vessels of a separate system that is called the lymphatic system.
• The fluid that enters the lymphatic vessels is called lymph.
• The lymphatic system is a part of circulatory system. The main function of it is to return
fluids escaped from capillaries to the circulation and also play an important role in defense
and immunity.
, Functions of the Lymphatic System
1. Tissue drainage: every day around 21 liters of fluid of plasma, carrying dissolved substances
and some plasma protein escape from the arterial end of the capillaries and into the tissues.
Most of this fluid is returned directly to the bloodstream via the capillary at its venous end,
but the excess, about 3-4 liters of fluid is drained away by the lymphatic vessels.
2. Returns the excess protein to the circulation.
3. Remove waste products and toxins.
4. Fat absorption: fat and fat soluble materials (e.g. fat soluble vitamin) are absorbed into the
central lacteals.
5. Essential to the immune system.
Components of Lymphatic System
I. Lymph
II. Lymph vessels
III. Lymph nodes
IV. Lymph organs
V. Diffuse lymphoid tissue
, I. The Lymph
• Lymph is a clear watery fluid, similar in composition to plasma, with exception of plasma
proteins (lymph contains small amounts of proteins).
• Lymph contains cells mainly lymphocytes, large molecules of fat (chylomicrons) that are
absorbed from the intestines enter lymph vessels.
Blood circulation, lymphatic circulation, and innervation of the small intestine. The smooth muscle
system for contracting the villi is illustrated in the villus on the right.
