Transcript Lymph nodes

Lymphatic System
Dr. Sama-ul-Haque
Dr. Rania Gabr
Objectives

Give functions of lymphatic System.

How a lymphatic vessel forms.

Define Lymphatics and its distribution in
body.
Functions
• 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 System
The lymphatic system is a specialized component of
the circulatory system that: 1- monitors body surfaces
and internal fluid compartment and 2- reacts against
potentially harmful substances.
It consists of:
 1- Lymph.
 2- Lymphatic vessels.
 3- Lymphatic cells.
 4- Lymphatic nodules.
 5- Lymphoid organs.
Lymph
Interstitial fluid:
Fluid that fills the spaces around cells.
Lymph
 Clear, watery fluid found in the lymphatic vessels.
 Lymph is a fluid similar in composition to blood plasma.
 Plasma filters into the interstitial spaces from blood
flowing through the capillaries.
 Much of this interstitial fluid is absorbed by tissue cells or
reabsorbed by the blood, small amount of interstitial fluid
is left behind.
 It is twice as blood in our body.
Origin of a lumphatic vessel
Lymphatic Vessels
 Lymphatic
vessels drain interstitial fluid
(cells and large macromolecules) from
tissues to venous blood.
 They begin as "porous" blind-ended
lymphatic capillaries in tissues of the
body and converge to form a number of
larger vessels, which ultimately connect
with large veins in the root of the neck.
Lymphatic vessels are found in most of
tissues and organs in the body but absent
from:
 CNS.
 Eye ball.
 Internal ear.
 Epidermis.
 Cartilage.
 Bone.

Structure of lymphatics

The lymphatics resemble veins in structure with these
exceptions:
 1-
Lymphatics have thinner walls.
 2-
Lymphatics contain more valves.
Lymphatics contain lymph nodes located at certain
intervals along their course.
Lymphatic circulation

Blind ended lymphatic capillaries.

Afferent lymphatics.

Lymph nodes.

Efferent lymphatics.

Thoracic duct/ Right lymph duct.

Blood circulation.
Main Lymphatic Channels
(Thoracic duct & Right lymph duct)
Cells of the Lymphatic 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 enter in
lymphatic system and pass directly to subepithelial 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 nodes
 Lymph nodes are small (0.1-2.5
cm long) encapsulated structures
that interrupt the course of
lymphatic vessels and contain
elements of the body's defense
system, such as clusters of
lymphocytes and macrophages.
Function

1- They act as filters that trap and
phagocytose particulate matter in the
lymph that percolates through them.

2- In addition, they detect and defend
against foreign antigens that are also
carried in the lymph
Lymph Flow
Lymph is driven by:
1- contraction of surrounding muscles,
2-valves enabling one-way flow.
3- breathing.
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