chapter iii the tissues and organs of immune system
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Chapter III The tissues and organs of immune system. Immune system immune organs or tissues bone marrow thymus spleen lymph nodes Immune cells : lymphocytes : T cells , B cells and NK cells - PowerPoint PPT PresentationTRANSCRIPT
Chapter III
The tissues and organs of immune system
Immune systemImmune system immune organs or tissuesimmune organs or tissues bone marrow bone marrow thymus thymus spleenspleen lymph nodeslymph nodes Immune cellsImmune cells : : lymphocytes : T cells , B cells and NK cellslymphocytes : T cells , B cells and NK cells phagocytes: Dendritic cells ,macrophage ,PMphagocytes: Dendritic cells ,macrophage ,PMN N immune moleculesimmune molecules : : antibodyantibody complement complement (( 补体)补体) cytokines cytokines adhesive molecules adhesive molecules
Immune organs Central immune organs or primary lymphoid organs The site that lymphocytes generate and mature into
functional cells Bone marrow or Bursa, and Thymus , Thymus , Peripheral immune organs or secondary
lymphoid organs and tissues The sites that T and B lymphocytes reside in and
respond to antigens spleen , lymph nodes , mucosal immune system
Immune organs
Section I Central immune tissues and organs
I. Bone marrow
1.The bone marrow is the site of generation of all circulating blood cells in the adult, including immature lymphocytes
2. The bone marrow is the site of B cell maturation
3. Bone marrow is the sites that secondary humoral immunity carries through
II. Thymus
1. The structure of thymus
Cortex outer cortex : immature T cells ( thymus cells) inter cortex : thymus epithelial cell, macrophage , DCMedulla Mature T cells + thymus epithelial cell, macrophage , DC
The structure of thymus
2. The function of thymus The thymus is the site of T cell maturation Secrete cytokine and thymulin-like molecules
Thymosin( 胸腺素) thymulin (胸腺刺激素) thymopoietin (胸腺生成素) To promote the proliferation , differentiation of t
hymus cells Barrier function : blood-thymus barrier
Development of T cell in thymus
Section II Peripheral Immune tissues and organs
The immune organs /tissues or secondary
lymphoid organs/tissues are sites that T and B
lymphocytes reside in and respond to antigens
spleen
lymphoid nodes
mucosal immune system
(mucosal-associated lymphoid tissues, MALT)
I. Spleen
1. The Structure of spleen white pulp Central arteriole periarteriolar lymphoid sheaths (PALS) T–cell area : around the central arteriole contain T cells , dendritic and macrophage B -cell area: lymphoid follicles contain B cells and macrophage and dendritic cells primary lymphoid follicle secondary lymphoid follicle Red pulp: cellular cords : B cells , plasma cells and macrophage ,DC venous: blood
T cells
B ells
2. Function of spleen
The site of T and B cells residence B cells : thymus-independent area T cells : Thymus –dependent area
Site of immune response to antigens
Synthesize some bioactive substance component of complete
Filtering blood
II. Lymphoid nodes
Structure of Lymphoid node( p38)
Cortex :
Outer cortex: thymus-independent area : B cell-rich area
lymphoid follicle/lymphoid nodule :
primary lymphoid follicle : without germinal center
mature and naïve B cells
secondary lymphoid follicle : with germinal center
activated B cells and memory B cells and macrophage
Paracortex : T cell-rich area+ dendritic cells Medulla :
medulla cords: macrophage and plasma cells medulla sinus
2. Function of lymphoid node
The site of T and B cells residence B cells : thymus-independent area T cells : Thymus –dependent area
Site of immune response to antigens
Part of Recirculation of lymphocytes
Filtering blood
III. Mucosal immune system
Mucosal immune system, also named as muc
osa-associated lymphoid tissue, MALT) is in
the epithelia , lamina propria and submucosa
l area of gastrointestinal, respiratory and ge
nitourinary tract
( I ) The constitution of MALT
Gut-associated lymphoid tissue, GALT
Nasal-associated lymphoid tissue, NALT
tonsils Bronchial-associated lymphoid
tissue, BALT : nodule
submucosa
( II ) The function and features of MALT
Local immunity
Secrete sIgA
Section III Lymphocytes homing and recirculation
I. Lymphocyte homing
The process by which particular subsets of
lymphocytes selectively enter some tissues
but not others is called lymphocyte homing
II. lymphocyte recirculation
The continuous movement of lymphocytes between blood stream and peripheral lymphoid tissues is called lymphocyte recirculation
1. Pathway of lymphocyte recirculation
2. Significance of lymphocyte recirculation
Blood Enter into paracortex of Lymphoid node
by high endothelial venules (HEV) in
efferent lymphatics Thoracic duct
Lymphoid node-blood recirculation
Tissue –lymphoid node-blood
recirculation
Tissues Afferent lymphatics
Lymphoid node
Blood
Spleen-Blood recirculation
Blood Enter into white pulp of spleen via cen
tral artery
spleen venule
Significance of lymphocyte
recirculation
Renew the lymphocytes in peripheral lymphoid organs
Maximize the chances of specific encounter with antigen and initiation of adaptive immunity
Enable lymphocytes to lymphoid tissue throughout body and facilitate immune response to antigen
Review
1.Terms
MALT, Central immune organs, Peripheral immune organs, lymphocyte recirculation, Lymphocyte homing
2. Questions :
Significance of lymphocyte recirculation
The function of thymus, bone marrow, spleen , LN and
MALT