Lymph Nodes Flashcards
What are lymph nodes?
Secondary lymphoid tissue (600 in body with 60-70 in H&N). -can be superficial or deep 2-2.5mm in size
What is the function of lymph nodes?
- Mechanical filtration of foreign substances 2. antigen presentation 3. lymphocyte activation (T and B cell) - proliferation and differentiation 4. chemokine release (attracts dendritic cells) 5. works in function with bone marrow. thymus and spleen
What is the basic structure of a lymph node?
resembles a kidney -cortex (inner and outer), medulla, with multiple afferent vessels and interductal communications
What does the outer cortex of the lymph node contain?
Outer cortex: Nodules for B cells, 1-2 follicles (gemination centers). outer layer inactivated b cells (dense), inner layer of outer cortex has secondary nodules of differentiating b cells)
What does the inner cortex of the lymph node contain?
Inner cortex: T cells (from Thymus), endothelial venules (HEV - where circulating lymphocytes enter, contain cuboidal cells that release chemokins to attract lymphs)) and dendritic cells (antigen presenting)
What does the medulla of the lymph node contain?
Medulla: rope like, contains plasma cells and lymph cells. plasma cells proliferate, AB production, B cell migrate, mast, lymph, plasma and immunoblasts
How are cells activated in lymph nodes?
CD4+ -> T helper cell -> 1 or 2 -> B cell in germinal center (already antigen presented) = activation and proliferation = plasma circulatory or memory.
How does movement occur within the lymph node?
Afferent v (valved) > subcapular sinus >trabecular sinus> Medullary sinus > efferent vessels (fewer than afferent)
What is MALT?
Mucosa associoated lymphoid tissues
- Tonsils. Have basic structures
1. 2x Lingual
2. 2x palatal
3. 1x pharngeal
= waldeyers ring
Where are the structures of Waldeyer ring?
1- Lingual Tonsils: circumvallete to the epiglottis, crypts by mucus glands, non keratinsed SSE and CT septas
- Palatal tonsils: between palatoglossus and palatopharngeus muscles, crypts seromucosa glands, non keratinised SSE, with CT septa.
- Pharngeal: single lymphoid mass, midline posterior of naopharynx , no cryps geminal centers, pseudostratified colunar with seromucus glands
Lymph drainage (robbins 2002) -Why is there a classification?
Benninger et al, 2011, A Head and Neck Lymph Node Classification Using an Anatomical Grid System While Maintaining Clinical Relevance that Aim to unify anatomical and clinical systems -surgical landmarks and patters on cancer metastasis -IA, IB, IIA, IIB, III, IV, V, VI
Lymph drainage -IA (anterior triangle)
Submental (IA): -Drainage: FOM, anterior tongue, ant mandibular ridge, lower lip -Boundaries: ant digastric, body of the hyoid, synthesis of the mandible
Lymph drainage - IB (anterior triangle)
Submandibular (IB): -Drainage: Ant nasal cavity, soft tissue of mid face, submandibular gland -Boundaries: body of the mandible, stylohyoid, ant/post belly of digastric
Lymph drainage - IIA/IIB
Upper Jugular (IIA, IIB): -Drainage: Oral cavity, nasal cavity, nasopharynx, oropharynx hypopharynx, larynx, parotid gland Boundaries: Base of skull, inf body of hyoid, stylohyoid, spinal accessory and SCM
Lymph drainage - III
Middle Jugular (III): -Drainage: Oropharynx, Nasopharynx, oral cavity, larynx -
Boundaries: inf hyoid, cricord cartliage, sternohyoid m, SCM
