Transcript Lymphatic System - Dr. Annette M. Parrott

Lymphatic System
Lymphatic System Functions
• Fluid & Protein Balance Return excess
interstitial fluid and leaked proteins to blood
• Digestion Lacteals transport dietary lipids
(chyle)
– Vitamins A, D, E and K from GI tract
• Immune Response
– Cell mediated immune responses—T cells destroy
intruders with cytotoxic substances.
– Antibody-mediated immune responses detect and
destroy specific foreign substances.
Lymphatic System Components
Lymph
• Fluid of the lymphatic system
• Similar to blood plasma and
interstitial fluid
Lymphatic Vessels
• Transport lymph
• Lymph is returned to the
circulatory system at either
the right or left subclavian
veins
Lymphoid tissues
• House phagocytic and
lymphoid cells
Lymphatic Vessels
• Lymphatic capillaries resemble veins but
have thinner walls and more valves.
• Lymph vessels in the skin follow veins.
• Lymph vessels in the viscera follow arteries.
• Lymph vessels are NOT found in avascular
tissue, CNS, parts of spleen and red bone
marrow.
Flow of Lymph
• Blood capillaries (blood) 
interstitial spaces  lymph
capillaries  lymph vessels 
lymph trunks  thoracic and
right lymphatic duct  junction
of the internal and subclavian
veins (blood).
• Smooth muscles in lymph
vessels contract rhythmically
• Pulsations in adjacent arteries
aid flow
• Skeletal muscle and respiratory
pump
Flow of Lymph
Lymphatics & the Breast
Lymphoid Cells
• Lymphocytes
– T-cells
– B-cells
• Macrophages
• Dendritic cells
• Reticular cells
Lymphoid Tissue
• Site for lymphocyte
residence and
proliferation
• Provides sentinel position
for lymphocytes and
macrophages
• Lymphocytes cycle among
lymphoid tissue, blood
circulation and loose
connective tissue.
• Can be diffuse or densely
organized
Lymph Nodes
2 Functions:
• Filter lymph
• Activate immune
system
– Microorganisms
– Cancer cells
Lymph nodes
2 Regions:
• Cortex
– B cells
– T cells
• Medulla
– Lymph Sinuses &
macrophages
Lymph Nodes Animation
Lymphoid Organs
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Lymph Nodes
Spleen
Thymus
Tonsils
Peyer’s patches
MALT
Spleen
• White pulp
– B and T cells carry
out immune function.
• Red pulp
– Removes aged and
defective RBCs
– Stores breakdown
products of RBCs
• Erythrocyte
production in fetus
• Stores blood
platelets
• Has regenerative
properties
Thymus
• Secretes
thymopoietin,
thmosins to make
T-cells
immunocompetent
• Bilobed organ
• Trabeculae divide
lobe into lobules.
• Thymic corpuscles
Tonsils & Adenoids
• Trap bacteria
which work
their way into
the follicles
where they
are
destroyed
• This helps
develop
memory
Appendix
• Possibly works
with the Peyer's
patches to help
defend against
invaders from the
digestive system
MALT
• Mucosa-associated lymphatic tissue
Causes of Edema
• Edema Accumulation of interstitial
fluid
• Blockage of lymphatic system
• Increased pressure in veins
• Lack of albumin
– Decreases fluid returning to blood
capillaries by osmosis
• Inflammation
Homeoimbalances of the
Lymphatic System
– Autoimmune Lymphoproliferative Syndrome
(ALPS)
– Lymphatic Filariasis
– Mesenteric Lymphadenitis
– Swollen Lymph Nodes
– Castleman Disease
– Adenoids
– Splenomegaly
– Hodgkin's disease
– Kawasaki disease
Nonspecific Body Defenses
• Skin
• Acid
– Stomach
– Vagina
• Mucus
• Saliva
• Tears
•Phagocytosis
•Complement
•Fever
•Inflammation
Complement
Inflammation
• Bodies response to tissue injury
• Classic signs
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Heat
Redness
Swelling
Pain