Anatomy and physiology of the palatine tonsil

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Anatomy and physiology of the palatine tonsil

  1. 1. ANATOMY AND PHYSIOLOGY OF THE PALATINE TONSIL By Dr. Syed Salman Hussaini PG in ENT
  2. 2.  OVERVIEW EMBRYOLOGY GROSS ANATOMY MICROSCOPIC ANATOMY FUNCTION IMMUNOLOGY
  3. 3. OVERVIEW The palatine tonsils are dense compact bodies of lymphoid tissue that are located in the lateral wall of the oropharynx. The palatine tonsil represent the largest accumulation of lymphoid tissue in Waldeyers ring. The Waldeyer ring is involved in the production of immunoglobulins and the development of both B-cell and T-cell lymphocytes.
  4. 4. WALDEYERS RING Waldeyers-Pirogov tonsillar ring (or pharyngeal lymphoid ring)
  5. 5. The ring consists of (from superior to inferior): Adenoids (superiorly in the nasopharynx). Palatine tonsils (laterally in the oropharynx). Lingual tonsils (inferiorly in the hypopharynx and posterior one-third of tongue). In addition, it includes lateral pharyngeral bands and scattered lymphoid follicles throughout the pharynx, particularly adjacent to the Eustachian tubes called Tubal tonsil. All structures in the Waldeyers ring have similar histology and similar functions (production of immunoglobulins and the development of both B and T cell lymphocytes).
  6. 6. WALDEYERS EXTERNAL RING Superficial Lymph Node System The component lymph nodes are: − Occipital − Post auricular − Parotid − Pre auricular − Facial or Buccal (superficial – upper, middle, lower; deep) − Submandibular − Submental − Superficial cervical − Anterior cervical
  7. 7. DEVELOPMENT Begins in 3rd month of I.U.L Ventral part of 2nd pharyngeal pouch (endoderm) Lymphocytes (mesodermal). 8-10 buds of pharyngeal squamous epithelium grow into pharyngeal walls Crypts
  8. 8.  8 weeks: Tonsillar fossa and palatine tonsils develop from the dorsal wing of the 1 st pharyngeal pouch and the ventral wing of the 2nd pouch; tonsillar pillars originate from 2nd/3rd arches. Crypts 3-6 months; capsule 5th month; germinal centers after birth.
  9. 9. GROSS ANATOMY
  10. 10.  SITUATION: The palatine tonsils occupy the tonsillar sinus or fossa between the diverging palatoglossal and palatopharyngeal arches. SURFACE MARKING SIZE: − Variable, 10-15 mm in transverse diameter and 20-25 mm in vertical dimension. − Bigger that which appears from the surface. FEATURES − Two surfaces − Two poles − Two borders
  11. 11. Medial Surface Covered by non-keratinizing stratified squamous epithelium. Tonsillar Crypts Crypta Magna orintra tonsillar cleft
  12. 12. Lateral Surface Well-defined fibrous tonsillar hemicapsule. Formed by the condensation of pharyngo basillar fascia. Loose areloar tissue between capsule and bed of tonsil. Palatine vein/external palatine/paratonsillar vein descends from the palate in the loose areloar tissue. Capsule is firmly attached anteroinferioly to the side of the tongue, just in front of the insertion of palatoglossus and palatopharyngeus muscles. Tonsillar artey enters near this firm attachment. The fascia extends into the tonsil forming septa for passage of vessels and nerves.
  13. 13.  UPPER POLE − Extends into soft palate − Semilunar fold/plica semilunaris (40%) − Supratonsillar fossa LOWER POLE − Attached to the tongue − Triangular fold/plica trangularis − Anterior tonsillar space − Tonsillolingual sulcus
  14. 14. Bed of tonsil Superior Constrictor (above) and Styloglossus (below). Glossopharyngeal Nerve and Stylohyoid ligament. Structures outside Superior Constrictor. Internal Carotid artery.
  15. 15. BLOOD SUPPLY Upper Pole − Descending Palatine br. Of Maxillay artery (Ant.) − Ascending pharyngeal artery br. Of Ext. Carotid artey (Post.) Lower Pole − Dorsal Lingual br. Lingual Artery (Ant.) − Tonsillar br. Of Facial Artery (Main) − Ascending palatine br. Of Facial Artery (Post.)
  16. 16.  VENOUS DRAINAGE − Paratonsillar vein – common facial vein – pharyngeal venous plexus – int. Jugular vein LYMPHATIC DRAINAGE − Upper deep cervical nodes particularly jugulodigastric (tonsillar) node. NERVE SUPPLY − Tonsillar br. Of Maxillary Nerve through Lesser palatine br. Of Sphenopalatine Ganglion − Glossopharyngeal N.
  17. 17. HISTOLOGY Oral aspect – Non-keratininzing stratified squamous epithelium Crypts greatly increase the contact surface – 295 cm2 4 lymphoid conpartments − Reticular cell/crypt epithelium − Extrafollicular area − Mantle zone of lymhoid follicle − Germinal centre of lymphoid follicle
  18. 18. IMMUNOLOGY Act as sentinels at the portal of aero-digestive system Secondary lymphoid organ Predominantly B-cell type Antigen uptake Weak antigenic stimulus: differentiation of lymphocytes to plasma cells. Strong antigenic stimulus: proliferation of B- cells in germinal centres. Most active: 4-10 years of age
  19. 19. REFERNCES 1. Scott-Browns Otorhinolaryngology, Head and Neck Surgery, 7th edition 2. Cummings Otolaryngology Head and Neck Surgery, 5th edition 3. Ballengers Otolaryngology Head and Neck Surgey, 17th edition 4. Grays Anatomy, 39th edition

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