Immune system

General outline

Lymphatic organs: thymus, lymph node,

Lymphoid tissue

Lymphocyte

T： Th、 Ts、TcBKNK

Macrophage

Cells

spleen, tonsil

Lymphoid tissue:

consists of reticular tissue, macrophage, plasma

cell and lymphocyte

diffuse L.T.: no border, predominant T cell ,

postcapillary venules (P.C.V.)

lymphoid nodules: clear border, predominantB cells

Primary ~ Secondary ~Ag

lymphoid tissue

Lymphoid organs

Central lymphoid organs

Thymus: the generation place of Tc

Bone marrow: the generation place of Bc

Peripheral lymphoid organs

Contain lymph node, spleen, tonsil

The places to proceed immune reactions

Thymus

Capsule ( C.T.) interlobular septa

Cortex: Endothelial reticular cell (ERC)

Lymphocyte: thymocyte

Macrophage: secrete IL-1

Medulla:

ERC

Lc: few

Macrophage: secrete IL-1

Thymic corpuscles

Structure:

Thymus

The cortex of thymus

The medulla of thymus

Blood-thymus barrier:

endothelial cell of continuous capillary

very thick basement membrane

perivascular space with macrophage in it

basement membrane of ERC

ERC or their processes with desmosome

Prevents circular antigens from reaching the thymic cortex where T cells are being formed

Consists of :

the thymic ERC can secrete thymic

hormones (thymosin, thymolin, thymopoietin)

induce the stem cell to differentiate into

T lymphocyte

Thymus function:

Lymph node

scattered in the passages of lymph

structure

capsule

parenchymaCortex

medulla

functionPerform immune reaction

Filtration of lymph

Structure:

capsule: several afferent lymphatic vessels,

trabecula cortex

superficial cortex:lymphoid nodule (B)

internodule zone

primary

secondary

paracortical zone: diffuse lymphoid tissue(T)

cortical lymphatic sinusessubcapsular sinus

peritrabecular sinus

Medulla

medullary cords:

contain many B cells, plasma cells, macrophages

medullary sinuses

many macrophages

Lymph node

The cortex of lymph node

The medulla of lymph node

Recirculation of lymphocytes:

Lymphoid tissue Efferent lymphatic vessel

P.C.V. Blood circulation

Spleen located in the passages of blood

structurecapsule

parenchymawhite pulp

red pulp

marginal zone function

immunefilter blood to clear out the old red blood cellshemopoiesisblood storage

Structure:

capsule: D.C.T. containing smooth muscle;

is covered by mesothelium

white pulp

periarterial lymphatic sheath: T predominant

lymphatic nodules (splenic nodules): B

marginal zone

lies between the white pulp and the red pulp

red pulp

splenic sinusoid

long rod endothelial cells ; gaps between the adjacent cells; no basement membrane; rounded by reticular fibers

splenic cord

the main components are B, Mφ, etc; is the principle place for filtration of blood

Spleen

The white pulp of spleen

The red pulp of spleen

Tonsil

Mucosa

Epithelium

stratified squamous epithelium

form crypts

lymphocyte infiltration

Lamina proprialymphatic nodules

diffuse lymphatic tissue

Capsule: C.T.

Tonsil

Mononuclear phagocyte system

Bone marrow

young monocyte

Blood

monocyte

Tissues or organs

CT: macrophageLiver: Kuffer cellLung: dust cellNerve tissue: microgliaOsseous tissue: osteoclastSkin: Langerhans cell

Function of MPS:

phagocytosis

participate in immune reaction

secrete bioactive substances