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EdrawMindMedical Immunology—Chapter 3 Immune Organs and Tissues
MindMap Gallery Medical Immunology—Chapter 3 Immune Organs and Tissues
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Medical Immunology—Chapter 3 Immune Organs and Tissues
Based on the fifth edition of the textbook "Medical Immunology and Pathogenic Microorganisms" compiled by Science Press, immune organs and tissues include two parts, the central and peripheral parts, each containing different organs and tissues; their structures and functions are different from each other.
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Medical Immunology—Chapter 3 Immune Organs and Tissues
- bacteria
This is a mind map about bacteria, and its main contents include: overview, morphology, types, structure, reproduction, distribution, application, and expansion. The summary is comprehensive and meticulous, suitable as review materials.
- Plant asexual reproduction
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- Reproductive development of animals
This is a mind map about the reproductive development of animals, and its main contents include: insects, frogs, birds, sexual reproduction, and asexual reproduction. The summary is comprehensive and meticulous, suitable as review materials.
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Chapter 3 Immune Organs and Tissues
central immune organ
Function: The place where immune cells occur, differentiate, develop, and mature; dominates the development of peripheral immune organs
include
marrow
structure
red bone marrow
hematopoietic tissue
Stromal cells: reticular cells, fibroblasts, macrophages, endothelial cells
hematopoietic cells
Sinusoids
yellow bone marrow
Function
The place where various types of immune cells occur
HSC→①myeloid stem cells (→ granulocytes; monocytes; DCs; red blood cells; platelets...) ②Lymphoid stem cells→T and B cells; NK cells; dendritic cells
The main site of B cell differentiation and development
Lymphoid stem cells → progenitor B cells → pre-B cells → immature B cells
The main site of antibody production
B cells in body fluids → plasma cells → migrate to the bone marrow → produce antibodies in the bone marrow (the main source of antibodies in serum)
Thymus
structure
External surface: connective tissue
Parenchyma: divided into lobules → outer cortex; inner medulla; rich blood vessels at the junction
Outer cortex: nursery cells (specialized epithelial cells) → multicellular complex → harboring multiple thymocytes
Medulla: Thymus subtopic (circle) - epithelial cells, macrophages, cell debris → signs of normal thymus development
cell
Thymocytes
Pre-T cells → thymocytes → immature T cells (cortex) → mature T cells (medulla)
TSC
Ingredients: TEC (main); macrophages, DCs, fibroblasts
Expression of surface molecules, thymic hormones, and cytokines → thymus microenvironment → necessary signals for thymocyte development
Function
The main place where T cells develop and mature
mature characteristics
Selective expression: TCR CD4 /CD8
MHC-restricted recognition of antigens
Negative selection: developing self-tolerance
Supracavitary bursa (bursa of Fabricius)—unique to birds
Peripheral immune organs and tissues
Lymph nodes
structure
Capsule: connective tissue
substance
cortex
Superficial cortical area (non-thymus dependent area)
B cell settlement site
Contains lymphoid follicles
Primary lymphoid follicle: not stimulated by antigen → no germinal center - contains quiescent initial B cells Follicular dendritic cells
Secondary follicle: stimulated by antigen → germinal center appears - B lymphoblast follicle helper T cell FDC
Deep cortical area (thymus-dependent area, paracortical area)
T cell colonization dendritic cells macrophages
High endothelial venules (HEV): involved in lymphocyte recycling
medulla
Medullary cord: Contains B cells, T cells, plasma cells, mast cells, and macrophages
Medullary sinus: high content of macrophages → strong filtration effect
Lymphatic vessels: afferent lymphatic vessels; efferent lymphatic vessels
Function
Immune cell settlement site
Approximately: T cells 75%; B cells 25%
Deep cortical area - differentiated and mature T cells
Superficial cortical area - B cells
Primary site of adaptive immune response
Antigen→lymph nodes→T/B cells recognize antigen→T/B cells activate and proliferate→effector T/antibodies→lymphatic vessels-thoracic duct-blood→effects on the site where the antigen exists
lymphocyte recirculation
Definition: The process of lymphocytes circulating repeatedly among blood, lymph, lymphoid organs, and tissues
Lymphocyte circulation process: blood circulation → (lymphocyte homing receptor-HEV pheromone) → HEV space → lymph node parenchyma → lymphatic vessels → thoracic duct → superior vena cava → blood circulation (entering local tissues)
Single cycle time: 24-48 hours
Function: Reasonably distribute lymphocytes → increase the chance of recognizing antigens and transmit immune information
filtration
Tissue (pathogenic microorganisms, toxins) → lymph → lymph node (macrophages/other mechanisms) clearance
spleen
structure
white marrow
periarterial lymphatic sheath
T cell residence
Lymph follicle
B cell residential area
Primary follicle → (stimulated by antigen) → secondary lymphoid follicle: distinguish between the presence and absence of germinal center
Red pith
Medullary cord: Contains lymphocytes, plasma cells, macrophages, and dendritic cells
Medullary sinuses: circulating blood
fringe zone
The junction of white pulp and red pulp
Blood and lymphocyte entry and exit channels
Function
Immune cell settlement site
Approximately: T cells 40%; B cells 60%
Mature lymphocytes colonize
Where adaptive immune responses occur
Important site for immune response to blood-derived antigens
Splenectomy: pathogenic bacteria in blood → bacteremia/sepsis
Synthesizes a variety of biologically active substances: cytokines, complements...
filtration
Macrophages, dendritic cells → remove pathogens, aging and dead self-cells, metamorphic cells, and immune complexes from the blood
Non-immune function: blood bank that stores red blood cells
mucosal immune system MIS
Also known as: mucosa-associated lymphoid tissue MALT
include
Respiratory tract, intestinal tract and genitourinary tract: unencapsulated lymphoid tissue scattered under the lamina propria of the mucosa and epithelial cells
Organized lymphoid tissue with germinal centers, such as tonsils, Peyer's patches of small intestine, appendix, etc.
structure
Gut-associated lymphoid tissue GALT
Peyer's patch lymph nodes, solitary lymphoid follicles, mesenteric lymph nodes, intraepithelial lymphocytes and lamina propria lymphoid tissue, etc.
Prevent infection from entering the intestines
route of uptake of antigens
Antigen → M cells (scattered distribution in mucosal epithelium, = membranous cells = microfold cells) → DC → T cells
Antigen→Protrusions of dendritic cells→Intestinal wall afferent lymphatic vessels→Mesenteric lymph nodes
Nasal associated lymphoid tissue NALT
Pharyngeal tonsils, palatine tonsils, lingual tonsils and retronasal lymphoid tissue
Prevent infection from entering through the air
Bronchial associated lymphoid tissue BALT
Distributed in: subbronchial epithelium
Structure: Similar to Peyer's patches
Function: Lymphocytes in follicles are stimulated by antigens and proliferate to form germinal centers to produce immune responses.
Functions and features
The place where local immune response occurs in the mucosa
Pathogen → Mucosal lamina propria innate immune cells → Innate immune response → Local inflammatory response → Mucosal local adaptive immune response → Clear pathogens
※Secretory IgA plays an important role in this process
The role of the common mucosal immune system
Memory cells generated after local mucosal immunization can migrate to other mucosal tissues to exert effects
For example: lymphocytes activated by GALT → play a role in the mucosal tissue of the urogenital tract
To commensal bacteria and food—low response/immune tolerance
Commensal bacteria: non-pathogenic microorganisms that colonize the intestinal tract