Transcript The lymphatic system

The lymphatic system
Clean and Kill
Ducts and Drains
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The lymphatic system is an extensive
drainage system that returns water and
proteins from various tissues back to the
bloodstream.
It is comprised of a network of ducts, called
lymph vessels or lymphatics, and carries
lymph, a clear, watery fluid that resembles
the plasma of blood.
Routemaster
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The entire lymphatic system flows toward the
bloodstream, returning fluid from body tissues
to the blood.
If there were no way for excess fluid to return
to the blood – extra cellular swelling.
The lymph vessels collect that excess fluid
and carry it to the veins through the lymphatic
system.
Why do we need the lymph?
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This process is crucial because water,
proteins, and other molecules continuously
leak out of tiny blood capillaries into the
surrounding body tissues.
This has to be drained, and so it returns to
the blood via the lymphatic vessels.
These vessels also prevent the back flow of
lymph fluid into the tissues.
Other jobs
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The lymphatic system also defends the body from
disease-causing agents such as viruses, bacteria, or
fungi.
Harmful foreign materials are filtered out by small
masses of tissue called lymph nodes that lie along
the network of lymphatic vessels.
These nodes have lymphocytes (wbc), some types
which produce antibodies, special proteins that fight
off infection and its spread by trapping diseasecausing germs and destroying them.
Transport of fatty acids
The Composition
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Lymph is composed of water, protein
molecules, salts, glucose, urea, lymphocytes,
and other minor substances.
They are in every part of the body except the
central nervous system
Size and Position
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Lymph nodes are round or kidney-shaped, and
range in size from very tiny to 1 inch in diameter.
They are usually found in groups in different places
throughout the body, - neck, armpit, chest,
abdomen, pelvis, and groin.
About two thirds of all lymph nodes and lymphatic
tissue are within or near the gastrointestinal tract.
The major lymphatic vessel is the thoracic duct,
which begins near the lower part of the spine and
collects lymph from the lower limbs, pelvis,
abdomen, and lower chest.
The Protectors
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Neutrophils – most common 60-70%
Lymphocytes – specialized 18-20%
Monocytes – long term memory – 1-2%
Basophils – super specialized – 0-1%
Macrophages – the large killers
White coats
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Lymphocytes are white blood cells in the
lymph nodes that help the body fight infection
by destroying foreign matter such as bacteria
or viruses.
Two types are T-cells and B-cells
Spleen
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The spleen also plays an important part in a
person's immune system and helps the body
fight infection.
Like the lymph nodes, the spleen contains
antibody-producing lymphocytes.
The blood passing through the spleen carries
damaged cells, white blood cells called
macrophages in the spleen will destroy them
and clear them from the bloodstream.
It helps control the amount of blood and
blood cells as it’s the only lymph tissue
through which rbc’s flow.
How does Lymph work?
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It moves more slowly than blood, pushed
along mainly by a person's breathing and
contractions of the skeletal muscles.
The walls of blood capillaries are very thin,
and they have many tiny openings to allow
gases, water, and chemicals to pass through
to nourish cells and to take away waste
products.
Take out the Recycling
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Lymph vessels recycle the interstitial fluid and return
it to the bloodstream in the circulatory system.
The nodes contain macrophages, that destroy
bacteria, dead tissue, and other foreign matter,
removing them from the bloodstream.
After these substances have been filtered out, the
lymph then leaves the nodes and returns to the
veins, where it re-enters the bloodstream.
Immunity
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When a person has an infection, germs
collect in great numbers in the lymph nodes.
If the throat is infected - the lymph nodes of
the neck may swell.
If the phagocyte cannot destroy all of the
germs - a local infection in the nodes may
result.
Cancer node?
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The lymphatic system extends to the far
reaches of the body, it also plays a role in the
spread of cancer.
This is why lymph nodes near a cancerous
growth are usually removed with the growth.