ImmuneLymphatic System 2 Lymphatic Organs

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Immune-Lymphatic System 2 Lymphatic Organs

• ANHB 2212 2006 Week 9
• Avinash Bharadwaj

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Mechanisms

• Nonspecific defence
• Specific defence
• Cellular attack
• Molecular (humoral) attack
• More than one mechanisms may be operating at a
  time!
• Cells involved
• White blood cells
• Macrophages
• Lymphocytes T and B
• Others
• Intricate interactions between cells molecular
  messengers

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Lymphoid (Lymphatic) Tissues

• Scattered lymphocytes and other cells
• Lymphatic nodule structural organisation
• Lymphocytes, macrophages, plasma cells, other
  leucocytes
• Outer zone (corona) and germinal centre
• Aggregates of lymphatic nodules
• Mucosa of GI Tract, respiratory system and other
  sites
• Larger aggregates Peyers patches (ileum),
  tonsillar tissue.
• Organised, encapsulated structures
• Lymph nodes
• Spleen special functions
• Thymus the academy

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Lymphatic Nodule

• Non-capsulated
• Single or aggregated
• Independent OR parts of other lymphoid organs
• Outer dark zone
• (Corona or cap)
• Germinal centre

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Lymphocyte Training - Thymus

• Lymphoid organ
• Anterior Mediastinum
• Foetal life ? Childhood ? Puberty
• Involution in adult life

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Thymus

• Capsule
• Lobules
• Cortex
• Medulla

• Hassals Corpuscles

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Regions and Cells
Epithelial reticular cells Lymphocytes Stages
of maturation Blood vessels Barrier

• Capsule
• Cortex
• Medulla

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Lymphocyte Training

• CFU-L
• Recognise antigen pass/fail
• Recognise self/non-self pass/fail
• Cytotoxic / Helper T cells

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B Lymphocytes

• Bursa of Fabricius
• Lymphoid organ in birds
• Bursa equivalent structures
• Bone marrow
• Gut and other mucosa-associated structures

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Tonsil

• A group of lymphoid structures
• Around the pharynx (GIT and RS)
• Lingual, palatine, tubal, nasopharyngeal
• Structurally similar

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Palatine Tonsil

• Epithelium of the pharynx
• Crypts
• Lymphatic nodules
• Connective tissue and pharyngeal muscle.

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Peyers Patches

• Ileum antimesenteric border
• Lamina propria ? submucosa

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Lymph Node

• Capsulated
• Afferent lymphatics ? subcapsular sinus
• Hilum blood vessels, efferent lymphatic
• Cortex and medulla
• Cortex
• Lymphatic nodules, germinal centres
• Paracortex
• Medulla
• Medullary cords and sinusoids

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C
M
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Lymph Node

• Lymphatics
• Afferent
• Efferent
• Blood vessels
• Lymphocytes
• Cortex
• Nodules (B)
• Deep cortex (T zone) Medulla (Cords, sinuses)

A
A
A
E
A
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Function
Antigens etc APCs Nodule B High Endothelial
Vv Medulla Plasma cells etc
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Spleen

• Lymphatic function lymph nodules (white pulp)
  around arterioles.
• Red pulp
• Sinusoids

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Last Slide