Transcript Lymphatic System

Lymphatic System
and
Axillary Lymph Nodes
Objectives
 Discuss Lymph, Lymphatic vessels, Lymphatic nodules
and Lymphoid organs.
 Enlist functions of lymphatic System.
 Explain Lymphatic circulation.
 Discuss Main lymphatic channels.
 Describe the axillary lymph nodes
- The lymphatic system
carries excess of the
extracellular fluid back
to the venous system.
- This fluid is the result of
filtration from capillaries.
- The lymphatic system consists of :
1. lymphatic vessels,
2. lymph nodes,
3. lymphatic ducts
4. Spleen.
1. Lymph vessels
- The lymph capillaries start as blind ended vessels
that collect to form lymphatic vessels which are
similar to the small veins (contain smooth muscles)
but contain valves so it has beaded appearance.
- In the intestine the lymphatics are called lacteals.
Superficial lymphatic
vessels:
* Present on the deep
surface of the
epithelium.
* They run parallel to
the superficial blood
vessels of the skin.
* They then join
together to form larger
vessels, which pierce
the deep fascia to join
the deeper vessels.
Deep lymphatic
vessels:
* They are deep to
the deep fascia,
parallel to the major
blood vessels.
* These are larger
than the superficial
vessels and have
thick wall and
valves.
2. Lymph Nodes
Definition:
- They are small oval
bodies along the
course of lymphatic
vessels.
Site:
- They form groups
especially in the
neck, axilla, thorax,
abdomen, and groin.
Structure:
- It has two surfaces:
a. Convex (outer)
surface:
- This surface receives
afferent lymphatics.
- Filtrations of its
contents occur inside
the lymph node.
b. Concave (inner)
surface:
- It is called the hilum.
- This surface gives
exit to an efferent
lymphatic in addition
to the presence of a
small artery and vein.
Functions of lymph nodes:
1. Act as a filter as they prevent microorganisms and certain substances from
entering the blood stream.
2. Formation of lymphocytes.
3. Formation of antibodies.
4. In case of infection or malignancy, the
lymph nodes become enlarged and
change in consistency.
3. Lymphatic Duct
- There are two lymphatic ducts thoracic duct and right lymphatic
duct.
a. Thoracic duct
- It begins in the cisterna chili
in the abdomen (in front of the
lumbar vertebrae)
- It ascends through the
posterior abdominal and
thoracic walls (deviating to the
left side).
- It terminates at the junction of
left subclavian and left internal
jugular veins.
- It drains lymph from all the
body except the upper right
quadrant.
b. Right lymphatic duct
- It is much smaller in
size.
- It drains lymph from
the upper right
quadrant (right side
of the head and
neck, right upper
limb, and right side
of the chest)
- It terminates at the
junction of right
subclavian and right
internal jugular veins
Other lymphatic aggregations:
They are seen in:
- tonsils.
- Mucous membrane of the intestine (Peyer's patches).
- Spleen.
- Thymus gland.
All parts of the body possess lymphatics except:
- C.N.S: its lymphatics is replaced by perivascular spaces that
are connected with the subarachnoid space.
- Bone marrow.
- Spleen.
On the other hand, certain parts of the body have a rich
network of lymphatics e.g. dermis of the skin, mucous, and
serous membranes and glands.
Axillary Lymph Nodes
Divided into 5 groups:
1- Pectoral (Anterior) group:
Site: on lower border of pectoralis
minor.
Afferents: from front of upper ½ of
trunk, and breast.
2- Scapular (Posterior) group:
Site: along subscapular artery
Afferents: from back of upper ½ of
trunk, and axillary tail of
breast.
3- lateral group:
Site: Along the axillary vessels.
Afferents: From upper limb.
Axillary Lymph Nodes cont.
4- Infraclavicular LNs:
Site: Below clavicle
Afferents: from upper part of
breast.
5- Apical group:
Site: At the apex of axilla
Afferents: from previous
groups. Efferents form the
subclavian trunk which enters
the thoracic duct or right
lymph trunk
Applied note:
Infection or malignancy in the
upper limb or breast give
swelling in the axilla due to
involvement of axillary LNs.