Practicals 3 Tonsils Introduction to teeth 27. 3. 2024 Tonsils – Waldeyer's ring Group of peripheral lymphoid organs positioned at the entrance into naso- and oropharynx Total 6 (tonsillae palatinae, tonsillae tubariae, tonsilla lingualis, tonsilla pharyngea) Mucosal organs – accumulation of lymphoid tissue in lamina propria B - dependent areas - secondary lymph follicles T - dependent regions - interfollicular zones Palatine tonsils Positioned on the right and left side between glossopalatal and pharyngopalatal arches, ovoid shape, deep and branched tonsillar crypts, there are usually up to 35 (contain detritus), tonsil separated by fibrous capsula – can have septs. The surface of the tonsil is covered by a stratified squamous epithelium In lamina propria are large lymphatic follicles with light germinal centers Brighter center - contains centroblasts Epithelium above nodules (differences): The structure of the epithelium and the contacts between the cells are very loose, caused by infiltration by lymphocytes, macrophages, dendritic cells, discontinuous basement membrane FAE – (follicle associated epithelium) A B A B Tonsilla palatina (H.E.) 1 – stratified squamous epithelium 2 – lymphocytes infiltrated epithelium (FAE) 3 – secondary lymph nodules or follicles 4 – detritus in tonsilar crypt Tonsilar crypt in detail (H.E.) 2 – with lymphocytes infiltrated epithelium 3 – germinal centre of a secondary nodule 4 – detritus Lymphocytes which penetrate into the oral cavity are referred to as salivary bodiesPalatine tonsils Palatine tonsils Group of lymph nodules (folliculi linguales) in the mucosa of lamina propria on the dorsal side of radix linguae behind the circumvallate papillae Surface covered by stratified squamous epithelium At the bottom of shallow crypts are openings of purely mucinous Webers glands (gll. Linguales posteriores) Crypts are perpetually washed outs – no detritus. No obvious capsula. Lingual tonsil Lingual tonsil Located on the top of pharynx (fornix pharyngis) From the other it differs by the surface covered by pseudostratified columnar epithelium which might contain goblet cells Shallow crypts In childhood tonsilla pharyngea can often be hypertrophic which cause problems with nose breathing Paired tonsil Group of small lymphoid tissue in lamina propria of mucosa in the pharyngeal opening of the eustachian tube (ostium pharyngeum tubae auditivae) Pharyngeal tonsil (Adenoid) Tubal tonsils (Gerlach tonsils) What are teeth? (Compagnucci et al., 2013) „Tooth“ as a term Functional view Embryonic view (Shi et al., 2021) (Krivanek et al., under review) What are teeth? Significant evolutionary diversity Calcified structures at the beginning of the digestive tract of jawed vertebrates (not all). • Mechanical food processing Tearing of food Crushing of food • Predation & killing Poisonous teeth (fangs) • Social interaction Defence Dominance Articulation • Sensory organ • Mechanical interaction with the environment Ohio State University Museum of Zoology www.deviantart.comwww.britannica.com https://en.wikipedia.org Function Significant evolutionary adaptation Function Classification of teeth Significant evolutionary adaptation Function Shape Topographic attachment in the jaw Functional attachment in the jaw Regeneration etc. Classification of teeth Shape of dentition Homodont Heterodont Anatomical attachment in jaw Acrodont Thecodont Pleurodont Functional attachment in the jaw Gomphosis Ankylosis Regeneration Number of generations Monophyodont Diphyodont Polyphyodont Capacity of growth Brachydont Hypsodont Hypselodont Aaron R. H. Le Blanc, Ph.D. etc. Basics in the phylogenesis and comparative tooth anatomy Teeth - calcified structures that derive from the ectoderm and ectomezenchyme (neural crest) Evolutionarily in phylogeny, they appear only in the jawed vertebrates – Gnathostomata Ancestor of teeth - placoid scales in fishes that covered the surface of the body and the oral cavity Lampres, cyclostomata Set of all teeth = dentition Set of all teeth = dentition Types of dentition Shape of teeth: homodont - identical in shape heterodont - different in shape (in mammals dentes incisivi, canini, praemolares and molares) According to the number of replacements (sets of teeth) during life: monofyodont - e.g., Holocephala - chimeras) difyodont (dentes decidui, dentes permanentes) – e.g. mammals polyphyodont - e.g., fish, lower amphibians According to the attachment of the teeth to the jaw: acrodont - attach to the jaw from above (bony fish, amphibians) pleurodont - on the jaw from the side (for reptiles) thecodont - inserted into dental sockets – recent mammals (dinosaurs, crocodiles) Set of all teeth = dentition Podle typu růstu zubů: Brachyodont - Long root Hypselodont - No root – continuously-growing Hypsodont - High crown (Mesodont) Diphyodont Heterodont Thecodont Brachydont Human dentition is: Tooth numbering Several possibilities Beginning letter incisors – dentes incisivi I1, I2/ i1 , i2 canines – dens caninus C / c premolars – dentes premolares P1, P2 molars – dentes molares M1, M2, M3 / m1, m2 Number international marking using "two-digit code" (ISO System - International Standards Organization Designation system: teeth divided into quadrants (clockwise): 1 - 4 dentes permanentes 5 - 8 dentes decidui Dentes permanentes Dentes decidui coronal vestibular (labial, bucal) apical lingual (palatinal) Directions Mesial (towards the midline) Distal (towards the last molar) S Tooth and dental socket, periodontium, gingiva crown, neck, root TERMINOLOGIE: Dentes decidui (lactei) 20 Dentes permanentes 28-32 Corona dentis (crown) Collum (neck) Radix (root) 1-3 Cavum et canalis radicis dentis (cavity and root canal) Pulpa dentis (pulp) Foramen apicis radicis (opening at the tip of the root) Alveolus Periodontium Tooth (dens) gingiva Cavitas dentis passing to canalis radicis dentis Anatomical vs clinical crown Anatomical vs clinical root Foramen apicis radicis Dentis Tissues of tooth Enamel - enamel, subst. adamantina (row adamas, adamantos = diamond steel), substantia vitrea (lat. vitrum = glass) Dentin - dentin, substantia eburnea (l. Ebur = ivory) Cementum - substantia ossea, crusta petrosa Dental pulp - pulpa dentis Babirusa Tusks 1) Thickness of hard dental tissues • Dentin and cement of temporary teeth is about half the thickness, enamel about 1/3 thinner 2) Permeability of dental tissues in permanent teeth decreases with age • In enamel, the differences between prisms and interprismatic matter become less pronounced with age due to the crystal growth • In dentin, the decrease in permeability is due to the reduction in the diameter of the dentin tubules 3) Chemical composition • The enamel of temporary teeth contains more nitro compounds than that of permanent teeth 4) Crown colour • For temporary ones, most often blue and white (combination of white and ivory) • In permanent ones, changes in the colour of the crown occur as a result of dentin thickening and darkening or as a result of the incorporation of substances from the external environment into the enamel - Incorporation of heavy metals (Pb, Hg) shades of yellow-copper to grey - Incorporation of dyes in toothpaste, tobacco or medicines - Incorporation of organic material into enamel 5) Abrasion of teeth • In permanent ones, due to abrasion, the dental arches may shift in a posterior to anterior direction 6) Position of longitudinal tooth axes • In the case of temporary ones, the axes are oriented perpendicular to the occlusal plane, the distal surfaces of temporary molars in one vertical plane • For permanents, the axes are inclined slightly distally, so that each tooth touches two opposing teeth at bite Differences in the anatomy and structure of priary and permanent teeth