Lymph Node and Tonsils-Dr. Darwish Badran

7/29/2019 Lymph Node and Tonsils-Dr. Darwish Badran

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Lymph

Node

DR. DARWISH H. BADRAN


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Lymph nodes are the principal lymphoidorgans of the body

Nodes are embedded in connective tissueand clustered along lymphatic vessels

Aggregations of these nodes occur near thebody surface in inguinal, axillary, andcervical regions of the body



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The two basic functions oflymph nodes are:

Filtrationmacrophages destroymicroorganisms and debris

Immune system activation

monitor for antigens and mountan attack against them



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Structure of Lymph Node ..1

Nodes are kidney shaped andsurrounded by a fibrouscapsule

Trabeculae extended inwardfrom the capsule and divide thenode into compartments

Nodes have two histologicallydistinct regions: a cortex and amedulla



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The cortex contains follicles with germinal centers,heavy with dividing B cells

Dendritic cells nearly encapsulate the follicles

The deep cortex houses T cells in transit

T cells circulate continuously among the blood,lymph nodes, and lymphatic stream



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Medullary cords extend from the cortex andcontain B cells, T cells, and plasma cells

Throughout the node are lymph sinusescrisscrossed by reticular fibers

Macrophages reside on these fibers andphagocytize foreign matter



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Circulation in Lymph Nodes

Lymph enters via a number of afferent lymphatic vessels

It then enters a large subcapsular sinus and travels into a number

of smaller sinuses

It meanders through these sinuses and exits the node at the hilusvia efferent vessels

Because there are fewer efferent vessels, lymph stagnates

somewhat in the node

This allows lymphocytes and macrophages time to carry outtheir protective functions



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Lymph Node



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Cortex

Medulla

Follicle

Efferent vessel

Pericapsular CT



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Tonsils



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Tonsils

Blue= palatine tonsil -----Green= lingual tonsil ------Red= pharyngeal tonsilDR. DARWISH H. BADRAN


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Simplest lymphoid organs; form a ring oflymphatic tissue around the pharynx

Location of the tonsils

Palatine tonsilseither side of the posterior end ofthe oral cavity

Lingual tonsilslie at the base of the tongue

Pharyngeal tonsilposterior wall of thenasopharynx

Tubal tonsilssurround the openings of the auditorytubes into the pharynx



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Lymphoid tissue of tonsils contains

follicles with germinal centers

Tonsil masses are not fully encapsulated

Epithelial tissue overlying tonsil massesinvaginates, forming blind-ended crypts

Crypts trap and destroy bacteria andparticulate matter



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Comparison of Tonsils

Palatine Pharyngeal Lingual Tubal

Lymph

Nodules

Subepithelial in position

Lymph Vessels No afferents; blind origins of efferent

Blood vessels Arteries enter through the attached surface

Capsule Prominent C.T Less definite Thin or absent absent

Cortex and

medulla

Absent

Hilum AbsentEpithelium Stratified

squamous

Respiratory Stratified

squamous

Respiratory

Diagnostic

features

Deep crypts

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No crypts Single crypt Associated withEustachian tube



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Palatine Tonsil

Blue= epithelial covering=

Capsule,Green= lymphatic nodulesDR. DARWISH H. BADRAN


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Palatine TonsilDR. DARWISH H. BADRAN


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Follicular tonsillitisDR. DARWISH H. BADRAN

Lymph Node and Tonsils-Dr. Darwish Badran

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