Lymphatic System

Dr. Sama-ul-HaqueDr. Sama-ul-Haque

Dr. Rania GabrDr. Rania Gabr

ObjectivesObjectives

Give functions of lymphatic System.Give functions of lymphatic System.

How a lymphatic vessel forms.How a lymphatic vessel forms.

Define Lymphatics and its distribution in Define Lymphatics and its distribution in

body.body.

FunctionsFunctions

• 1- Remove excess fluids from body tissues & transport

of tissue fluid back into the blood circulation.

• 2- Absorb & remove large Protein molecules.

• 3- Absorb fatty acid and transport fat to circulatory

system from intestinal villi.

• 4- Produce immune cells. (lymphocytes, monocytes & plasma cells).

The Lymphatic SystemThe Lymphatic System

The lymphatic system is a specialized component of the The lymphatic system is a specialized component of the circulatory system that: 1- monitors body surfaces and circulatory system that: 1- monitors body surfaces and internal fluid compartment and 2- reacts against internal fluid compartment and 2- reacts against potentially harmful substances. potentially harmful substances.

It consists of:It consists of: 1- Lymph.1- Lymph. 2- Lymphatic vessels.2- Lymphatic vessels. 3- Lymphatic cells.3- Lymphatic cells. 4- Lymphatic nodules.4- Lymphatic nodules. 5- Lymphoid organs.5- Lymphoid organs.

LymphLymph

Interstitial fluid:

Fluid that fills the spaces around cells.Fluid that fills the spaces around cells.

Lymph Clear, watery fluid found in the lymphatic vessels.Clear, watery fluid found in the lymphatic vessels.Lymph is a fluid similar in composition to blood plasma. Lymph is a fluid similar in composition to blood plasma. Plasma filters into the interstitial spaces from blood Plasma filters into the interstitial spaces from blood

flowing through the capillaries. flowing through the capillaries. Much of this interstitial fluid is absorbed by tissue cells or Much of this interstitial fluid is absorbed by tissue cells or

reabsorbed by the blood, small amount of interstitial fluid reabsorbed by the blood, small amount of interstitial fluid is left behind.is left behind.

It is twice as blood in our bodyIt is twice as blood in our body..

Origin of a lumphatic vesselOrigin of a lumphatic vessel

Lymphatic Vessels

Lymphatic vessels drain interstitial fluid (cells Lymphatic vessels drain interstitial fluid (cells and large macromolecules) from tissues to venous and large macromolecules) from tissues to venous blood.blood.

They begin as "porous" blind-ended lymphatic They begin as "porous" blind-ended lymphatic capillaries in tissues of the body and converge to capillaries in tissues of the body and converge to form a number of larger vessels, which ultimately form a number of larger vessels, which ultimately connect with large connect with large veinsveins in the root of the neck. in the root of the neck.

Lymphatic vessels are found in most of Lymphatic vessels are found in most of tissues and organs in the body but tissues and organs in the body but absentabsent from: from:

CNS.CNS.Eye ball.Eye ball. Internal ear.Internal ear.Epidermis.Epidermis.Cartilage.Cartilage.Bone. Bone.

Structure of lymphaticsStructure of lymphatics

The lymphatics resemble veins in structure with these The lymphatics resemble veins in structure with these exceptions: :

1- Lymphatics have thinner walls. 1- Lymphatics have thinner walls.

2- Lymphatics contain more valves.2- Lymphatics contain more valves.

Lymphatics contain lymph nodes located at certain intervals along their course. Lymphatics contain lymph nodes located at certain intervals along their course.

Lymphatic circulationLymphatic circulation

Blind ended lymphatic capillaries.Blind ended lymphatic capillaries.

Afferent lymphatics.Afferent lymphatics.

Lymph nodes.Lymph nodes.

Efferent lymphatics.Efferent lymphatics.

Thoracic duct/ Right lymph duct.Thoracic duct/ Right lymph duct.

Blood circulation.Blood circulation.

Main Lymphatic Channels(Thoracic duct & Right lymph duct)

Cells of the Cells of the LymphaticLymphatic System System

Lymphocytes are the chief cells of lymphatic system with supporting cells.

About 70% of lymphocytes circulate in blood and lymphatic circulation.

About 30% of lymphocytes do not do not enter in lymphatic system and pass directly to sub-epithelial tissues for surveillance.

Lymphatic organs

Primary lymphatic organs

Organs where lymphocytes become initially immunocompitant e.g.1- bone marrow

2-thymus.

Secondary lymphatic organs Organs where immunocompitant lymphocytes form effector lymphatic tissue and organs

e.g.1- lymphatic nodules, 2-lymph nodes, 3-tonsils and 4-spleen.

Lymph nodesLymph nodes Lymph nodes are small (0.1-Lymph nodes are small (0.1-

2.5 cm long) encapsulated 2.5 cm long) encapsulated structures that interrupt the structures that interrupt the course of lymphatic vessels course of lymphatic vessels and contain elements of the and contain elements of the body's defense system, such body's defense system, such as clusters of lymphocytes as clusters of lymphocytes and macrophagesand macrophages. .

FunctionFunction

1- They act as filters that trap and 1- They act as filters that trap and phagocytose particulate matter in phagocytose particulate matter in the lymph that percolates through the lymph that percolates through them.them.

2- In addition, they detect and 2- In addition, they detect and

defend against foreign antigens that defend against foreign antigens that are also carried in the lymphare also carried in the lymph

Lymph FlowLymph FlowLymph is driven by:

1- contraction of surrounding muscles,

2-valves enabling one-way flow.

3- breathing.

Thank YouThank You