THE LYMPHATIC SYSTEM

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THE LYMPHATIC SYSTEM

• Overview
• Essential functions
• 3. Lymphatic vessels
• 4. Formation and flow of lymph
• 5. Lymphatic trunks
• 6. Lymphatic ducts
• 7. Lymphoid tissue
• Lymph nodes
• Lymph node distribution
• Tonsils
• Spleen
• Thymus gland
• Resistance to disease
• Lymphocytes and immunocompetence
• Cell-mediated immunity
• Antibody-mediated immunity

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OVERVIEW
Lymph Lymphatic capillaries Lymphatic tissue and
lymphocytes Bone marrow
thymus gland
lymph nodes
lymphatic vessels
spleen
bone marrow
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ESSENTIAL FUNCTIONS
drain interstitial fluid back to blood protect
against pathogens absorb and transport dietary
lipids
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FORMATION AND FLOW OF LYMPH
Starlings law Lymph
lymphatic capillaries
lymph node
pulmonary capillaries
interstitial fluid escaped plasma proteins
lymphatic trunks and ducts
Flow of lymph
no official pump one-way valves pressure
gradient skeletal muscle pumps respiratory pump
systemic capillaries
lymph node
lymphatic capillaries
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LYMPHATIC TRUNKS
Lumbar (rt and lt) Intestinal Bronchomediastinal
(rt and lt) Subclavian (rt and lt) Jugular (rt
and lt)
left jugular trunk
right jugular trunk
left subclavian trunk
right subclavian trunk
left bronchomediastinal trunk
right bronchomediastinal trunk
right lumbar trunk
left lumbar trunk
intestinal trunk
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LYMPHATIC DUCTS
Left lymphatic duct (thoracic duct)
cisterna chyli location drainage field termination
thoracic duct
right lymphatic duct
union of left jugular and left subclavian veins
where the left brachiocephalic vein is formed
cisterna chyli
Right lymphatic duct
right jugular trunk
left jugular trunk
location drainage field termination
right subclavian trunk
left subclavian trunk
left bronchomediastinal trunk
union of right jugular and right subclavian veins
where the right brachiocephalic vein is formed
right bronchomediastinal trunk
thoracic duct
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LYMPHOID TISSUE
What are lymphoid (lymphatic) tissues?
Lymphoid tissues occur in the body in four ways
diffuse lymphatic tissue (MALT, GALT,
BALT) lymphatic nodules primary lymphatic organs
bone marrow and thymus gland secondary
lymphatic organs lymph nodes, tonsils, and
spleen
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LYMPH NODES
Capsule Trabeculae Stroma Parenchyma
LYMPH IN
trabeculum
capsule
LYMPH IN
medullary cords
lymphatic nodules with lymphocytes
macrophages germinal centers medullary cords
subcapsular sinus
LYMPH OUT
Flow of lymph
LYMPH IN
afferent lymphatics subcapsular sinus ? toward
hilus efferent lymphatics
lymphatic nodule with germinal center
afferent lymphatics
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LYMPH NODE DISTRIBUTION
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TONSILS
Locations
uvula
palatine (2) lingual (numerous) pharnygeal
(adenoids) (1)
palatoglossal arch
Parenchyma Crypts Function
palatine tonsils
hard palate
pharyngeal tonsil
palatine tonsil
tongue
lingual tonsils
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SPLEEN
Location Parenchyma
spleen
white pulp red pulp
Functions
monitor blood for antigens phagocytosis of old
RBCs blood storage
splenic artery and vein
arteriole of the pulp
capillaries
white pulp
capsule
red pulp
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THYMUS GLAND
Location Parenchyma Functions
thymus gland
Development of T lymphocytes Secretion of
signaling molecules
Involution with aging
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RESISTANCE TO DISEASE
What is a pathogen?
What is an antigen? What does it mean to
distinguish self from nonself?
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LYMPHOCYTES AND IMMUNOCOMPETENCE
T cells (thymus gland) cell-mediated immunity B
cells (bone marrow) antibody-mediated (humoral)
immunity
red bone marrow
thymus gland
other lymphatic tissue and organs
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CELL-MEDIATED IMMUNITY
Directed against
antibody-presenting cell
intracellular pathogens (viruses) some cancer
cells tissue transplants
Antigen recognition
TC or TH
Phases
recognition
Costimulation
antigen presentation T cell activation
costimulation clonal selection
TC
TH
TM
Clonal selection
attack
effector cells
memory cells
helper T cells cytotoxic T cells
Lethal hit
interleukin secretion
enemy cell
memory
destruction of enemy cell
activity of NK cells, B cells, and TC
cells development of TM cells
memory T cells anamnestic response
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ANTIBODY-MEDIATED IMMUNITY
Directed against
antigen
imunocompetent B cells
extracellular antigens
Antigen recognition
Phases
recognition
helper T cell
Antigen presentation
antigen binds to B cell receptors B cell
activation clonal selection plasma cells
memory B cells
B cell
Clonal selection
attack
Differentiation
plasma cell secrete antibodies antibodies mark
antigen for destruction
plasma cells
memory B cells
Attack
memory
Ab-Ag complex renders antigen harmless by
neutralization complement fixation
agglutination precipitation
memory B cells anamnestic response
end