The Lymph
System and
Lymphoid
Organs and
Tissues
Overview
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lymphatic vessels
lymph
lyphoid cells and tissues
lymphoid organs
lymph nodes
o spleen
o thymus
o tonsils
o other lymphoid tissue
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lymphatic vessels
collects excess
interstitial fluid
returns fluid to blood
one way system
o
flows toward the heart
lymphatic vessels
lymphatic
capillaries
- cells
overlap
- collagen
filaments
anchor
ends
lymphatic vessels
lacteals
- specialized lymph
capillaries in lining
of small intestine
- absorb fats
- chyle = fatty lymph
that is milky white
- moves into lymph
vessels
lymphatic vessels
lymphatic collecting
vessels
- similar structure to
veins
- more valves
- reconnect
(anastamose) more
often
lymphatic
vessels
lymphatic trunks
- formed by
union of
largest
vessels
lymphatic
vessels
lymphatic ducts
- right
- thoracic
- cisterna
chyli enlarged sac
where lumbar
trunks meet
lymphatic
vessels
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lyphangitis
o
when lymph vessel is
inflamed, blood vessels
that feed them become
congested with blood
lymph
- similar to blood
plasma
- white blood cells
- debris/pathogens
lymph transport
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no pump
skeletal muscles
muscles used to breathe
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diaphragm
intercostal muscles
smooth muscle in lymphatic trunks and
thoracic duct
valves prevent backflow
arterial pumping
lymph transport
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lymphedema
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flow is blocked
lymph vessels removed
lymph vessels can
regrow!
lymphoid cells
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lymphocytes
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T cells
B cells
macrophages
dendritic cells
reticular cells
lymphoid tissue
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houses and
provides a site
for proliferation
of lymphocytes
surveillance
point for
lymphocytes
and
macrophages
lymphoid tissue
types
diffuse
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found in every
body organ
o scattered
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lymphoid
follicles
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solid spherical
bodies
germinal
center
lymph nodes
clusters
- inguinal
- axillary
- cervical
functions
- filter lymph
- help activate the
immune system
lymph nodes
- average 1" bean
shaped
- capsule with
trabeculae
- cortex
- medulla
lymph nodes
flow through node
- afferent lymph
vessels
- efferent lymph
vessels
spleen
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size of fist
largest lymphoid
organ
site of lymphocyte
proliferation
site of immune
surveillance
spleen
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cleans the blood
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stores and releases
breakdown products of
RBCs
stores blood platelets
site of RBC production
in fetus
spleen
spleen
thymus
thymus
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many thymic lobules
cortex
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rapidly dividing
lymphocytes
medulla
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thymic corpuscles
 development of
regulatory T cells
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prevent autoimmune
diseases
tonsils
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palatine tonsils
lingual tonsil
pharyngeal tonsil
tubal tonsils
tonsils
tonsillar crypt
other lymphoid tissue
Peyer's patches
- aggregated
follicles in the far
end of the ileum
and appendix
- immune
function of GI
tract
other lymphoid tissue
MALT - mucosa-associated lymphatic tissue
- Peyer's patches
- appendix
- tonsils
- lymphoid follicles in bronchi
- lymphoid follicles in genitourinary organs