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Unformatted text preview: Lymhatic System Today’s topics
What is the lymphatic system
Composition of lymph
Formation of lymph
Transportation of lymph
The transportation system
What are lymph nodes
What Lymphatic System
The lymphatic system consists of a
unique set of vessels separate from
the circulatory system that includes a
These vessels lack a pump such as a
heart and must depend on other
means to transport the fluid. Compositon of lymph
Thus fluid, called interstitial fluid, is simply
blood plasma minus most of the proteins.
When blood enters the arteriole end of a
capillary, it is still under pressure produced by
the contraction of the left ventricle. As a result
of this pressure, a substantial amount of water
and some plasma proteins filter through the
walls of the capillaries into the interstitial
space. Composition of Lymph
The lymph is clear although it has many
components of blood it lacks erythroctyes
(RBC’s) and thrombocytes (platelets).
Naturally the red blood cells would cause
the lymph to be red similar to blood not
clear. Formation of lymph
The lymph forms when the interstitial fluid
escapes from spaces and enters a lymph
The fluid in the interstitial spaces is known
as interstitial fluid.
When this fluid enters a lymph vessel it is
then called lymph.
It has the same elements as interstitial fluid
the location is the reason for the name
change. 1 Lymph vessels Lymph capillary working The smallest of the lymph vessels would
be the lymph capillaries.
These vessels have one way valves that
allow the interstitial fluid to enter the
lymph capillaries but not escape. 1-way valve Lymphatic System Following the lymph
The lymph moves from the lymph
capillary to larger lymph vessels.
The lymph vessels have enlarged
swollen-like structures on them called
swollenlymph nodes. Lymph nodes
Several hundred lymph nodes are
scattered throughout the lymphatic
system, especially in the
neck. Function of lymph nodes
These contain cavities - called sinuses These
into which the lymph flows. The walls of
the sinuses are lined with phagocytic
cells, which engulf any foreign particles,
e.g., bacteria, that might be present in
the lymph. Tests have demonstrated that
over 99% of the bacteria carried into a
node are screened out before the lymph
leaves the node on its return to the blood. 2 Lymph node from a cat Lymph node (details) Size of a large pea Location of lymph nodes Lower lymph nodes Lymph vessels go here Thoracic duct All of the lymph vessels dump into one of two
All the lymph collected from the entire
left side of the body,
the digestive tract and
the right side of the lower part of the body
flows into a single major vessel, the thoracic
duct ( also known as left lymphatic duct) 3 One third of lymph goes to
the right lymphatic duct.
The right upper quadrant dumps into the
right lymphatic duct.
Thus all the lymph is returned to the
The lymph originated from the blood and
returned to the blood. IF no heart why does it
Lymph vessels surrounded by
smooth muscle which contracts
myogenically & propels lymph
Lymph vessels lie between skeletal
muscles; lymph is also propelled
forward by skeletal muscle contraction Lymph flow continued
By breathing the thorax creates a vacuum
that draws the lymph toward the thoracic
cavity where the thoracic duct is found.
The production of new lymph also propels
the lymph away from the interstitial
spaces and into lymph capillaries. Other interesting websites Pohala’s Home website
This presentation can be viewed as a
slide show or printed out in a handout
version by going to the website and
clicking on links and choosing lymphatic
system and choosing whether to view as
a slide show or print out. More websites http://www.acm.uiuc.edu/sigbio/project/ly
ymphatic2/lymphatic2.html 4 ...
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This note was uploaded on 02/28/2012 for the course BIO 1101 taught by Professor Robinson during the Spring '09 term at University of Central Florida.
- Spring '09