Digestive systemOral cavity

1. Digestive system general feature 2. Oral cavity (lips, cheek, gingiva, soft and hard palate)

3. Tongue4. Salivary glands5. Tonsils6. Teeth 7. Periodontal membrane8. Development of teeth

Digestive system = digestive tube + glands

Oral cavityFunctionsІ. Main 1. Digestion (ingestion,

mastication)2. Moistening of food

ІІ. Additional 1. Articulation2. Facial expression3. Sensory reception4. Respiratory

І. Mucosa1. Еpithelium – stratified squamous nonkeratinized epithelium (180-600 mkm)2. Lamina propria – loose connective tissue3. Muscularis mucosa-smooth muscular tissue

ІІ. Submucosa - loose connective tissue (glands)

Lips

1. Hear-bearing skin : а) epithelium stratified squamous keratinized (4 layers)

• b) lamina propria (loose connective tissue with hair follicles sweat and sebaceous glands)

2. Transitional (vermilion): external (smooth) and internal zone

3. Mucosal а) epithelium stratified squamous nonkeratinized b) lamina propria (papillae)

• c) submucosa

Lip

Minor salivarygland

Musculusorbicularis oris

Hair follicles

Skin surface

Sweat gland

Papillae of connective tissue

Blood vessel

Mucosa surface

Red borderof lip

TongueFunctions1. Mechanical2. Receptory (general and taste)3. Articulation TunicesІ. MucosaІІ. SubmucosaІІІ. MuscularІV. Aponeurosis

Morphofunctional peculiarities of the lover surface of the tongue1. Thin permeable epithelium 2. Well prominent blood supply 3. Salivary glands

CheeksCheek surfaces1. External (skin)2. Internal (mucosa)• І. Skin • ІІ. Muscle• ІІІ. MucosaMucosa zones1. Upper (maxillary)2. Lover (mandibulary)3. Intermediate (no salivary glands, parotid glands ducts)1. Mucosa• а) stratified squamous nonkeratinized epithelium (smear);• б) lamina propria (dense connective tissue, elastic fibers).2. Submucosa (salivary glands).3. Muscular tunic (skeletal muscle). Adipose body of Bisha.

Palate

• Separates oral and nasal cavity• І. Hard palate• Zones 1. Adipose• 2. Mucous• 3. Marginal• 4. Middle line (epithelial bodies)• ІІ. Soft palate • Oral surface (strutified squamous nonkeratinized

epithelium)• Nasal surface (ciliated epithelium)

Tonsils• Lymph epithelial ring of Pirogov-Waldeier

7 tonsils : 2 tubular, 2 palatine, lingual, pharyngeal, laryngeal

Functions 1. Protective2. Immune

І. Mucosa:а) epithelium stratified squamous nonkeratinized infiltratedb) lamina propria – loose connective tissue with B lymphocytes)

ІІ. Submucosa – septae, capsuleІІІ. Muscular tunic skeletal muscle

Tonsil

Stratified squamousnonkeratinized

epithelium

Skeletal muscle

Crypt

Connective tissue septae

Lymph nodules

Crypt

Salivary glands major (3pairs) + minor

Functions 1. Exocine (saliva secretion)

2. Desinfection 3. Digestion4. Articulation

2. Endocrine (parotin, VIP, glukagon, kallikrein, renin ...)3. Excretion4.Homeostatic

Saliva Water -99%Minerals (Na, K, Cа, Fe, I…)Organic matters (enzymes, mucous)Cells (leucocytes, epithelial)

MFU – Acinus = secretory portion+ intercalated duct+ striated duct

Intercalatedducts

Myoepithelialcells

Intercellularcanaliculi

Myoepithelial cells

Serousdemilunar

Mixed acinus

Striated duct

Intercalated duct

Serousacinus

Serocytes

Mucous acinusMucocytes

Basementmembrane

Teeth 1. Functions 2. Structure 3. Deciduous and permanent teeth4. Enamel 5. Dentin 6. Cementum 7. Pulp 8. Periodontal membrane9. Development of teeth

• Functions

1. Mastication

2. Articulation

3. Esthetic

Lip, tooth, gingiva

• red boarder

skeletal muscle

minor salivary glands

skin with hair

cementum

tooth apex

channel of tooth

enamel

gingival fissure

periodontum

pulp

dentin

muscle

gingiva

alveolar bone

lip furrow

mandible

Deciduous teeth (20) 1. Smaller 2. Crown lower and wider3. Shorter roots

Incisors central and lateralCuspids (canines)Molars Eruption – 6 months- 2 years 12 years

Permanent teeth (32)IncisorsCuspids Bicuspids (premolar)sMolars

Eruption -

2012/21022012/2102

3212/21233212/2123

Enamel

1. Covers crown

2. 2,5 mm

3. Hardest tissue

Chemical composition

1) 96-97 % – mineral salts (Са hydroxyapatites, fluorides, carbohydrates)

2) 3-4 % – organic substance (fibrillar matrix)

MFU – hexagonal enamel rod (S-shaped enamel prism)

Retzius, 1835

5-12 mln in tooth

4-8 мm

Enamel rods

Rods are formed by ameloblasts

Fur – microorganisms and + mineral and organic substances

Pellicle - glycoproteins

(II keratinous membrane)

Cuticle – ameloblats remnants (I Nasmyth’s membrane)

Enamelorgan

reticulum

Apicalterminal bar

Basalterminal bar

RER

Tome’s process

Golgi complex

Nucleus

Mitochondria

Enamel

Secretorygranules

Enamel lamellae –thin leaflike structures

(septae)

Enamel bundles - near dentino-enamel junction

Enamel tuft (spindle)

Retzius incremental lines

Hunter-Schreger bands

Dentin

Enamel

Dentin

Chemical composition

1) 72 % – mineral salts (Са and Mg phosphates, carbohydrates, fluorides)

2) 28 % – organic substance (collagen fibers)

Calcified dentin - dentinal tubules with Tomes’ fibers

Mantle dentin (radial Korff’s fibers)

Inner dentin (tangential Ebner fibers – imbrication lines)

Contour lines of Owen

Uncalcified dentin – predentin (odontoblasts in pulp)

Peritubular dentin – Neumans’ sheath (less fibers)

Intertubular dentin – contains calcium crystals and globules

(linear and globular calcification)

Interglobular dentin – hypocalcified ground substance

Tomes’ granular layer- a thin layer of dentin adjacent to cementum (in the root)

Peritubulardentin

Dentin tubules

Odontoblastprocess

Dentin cross section

Intertubulardentin

Dentintubul

Peritubulardentin

Intertubulardentin

Dentin

Odontoblastsprocess

Odontoblastnucleus

Predentin

Odontoblasts

Pulp

Odontoblast

1. Lies in the pulp

2. Produces dentin

3. Promotes regeneration

Dentin tubule

Dentin

Predentin

RER

Calcificationzone

Odontoblastprocecss

Terminal bar

RER

GA

Mitochondria

Odontoblastnucleus

Primary dentin - regular

Secondary dentin – forming pulpward of the

demarcation line (on the pulpal surface)

Transparent dentin – sclerotic (Ca salts are deposed in tubule and oblitarate it )

Dead tract (black)- empty tubules are filled with air

Denticles – pulp stones

1. True (tubuli and cells) 1. Free (in pulp)

2. False (concentric calcified) 2. Adherent (attached)

3. Diffuse calcifications 3. Embedded (in dentin)

Cementum 1835 two Purkinje pupils

1. Cellular (cementocytes)

2. Acellular

Chemical composition

1. 65 % – inorganic substances

(Са(РО3)2, СаСО3)

2. 23 % – organic material

(collagen fibers and ground substance)

3. 12 % – water

Cemento-enameljunction

Apical foramen

Root

Odontoblasts

Pulp – soft tissue

Functions1. Formative2. Nutritive3. Sensory 4. Protective

In the crownIn the root

Pulp layers

1. Peripheral – odontoblasts and immature collagen fibers

2. Intermediate – preodontoblasts and precollagen fibers– Acellular zone of Weil

(cell-free layer in the crown of old teeth)

3. Central – loose connective tissue with blood vessels and nerves

Periodontal membrane

(ligament)

1. Formative

2. Supportive

3. Sensory

4. Nutritive

Epithelial rests of

Malassez (Hertwig’s

epithelial root sheath)

Cementicles

Parodontum = gingiva + alveola + periodontum

Circular ligament (10 )

Periodontum: 1) marginal (4)

2) proper (2)

Developmentalstages

1. Dental laminaand bud

2. Enamel organ(cap and bell stage)

3. Histogenesis, organogenesis

TongueDeciduous tooth bud

DPMesenchyme

MaxillaMaxilla

Dentalpapilla

Enamel organDental

Lamina DL

Low lip

Dental papilla

A

DC

B

Enamelorgan P

Dentalpapilla P

Maxilla

Dental sac

Low lip

Enamel organ

Dentin

Enamel

Pulp

DL remnant

Dentin

ReducedEO

EnamelPermanent

tooth

Dental lamina

Tooth eruption and replacement

1870 Hunter – root growth

1929,1936 Jasvoin – dental pupilla

1940 Kutz – bony tissue +pressure in pupilla

Dental sac

Enamelorgan

EnamelDentinPulp

Dental sac

Osteoclasts

DentinPulp

Periodontum

EnamelPermanent tooth

Pulp

Enamel

Dentin Periodontum

EnamelDentin

Pulp

Deciduous tooth Zone of eruption

Permanent tooth

Teeth eruptionDeciduous

(months)

No Teeth Permanent (years)

First molar 5-6

6-8 1 Incisor central 7-8

8-12 2 Incisor lateral 8-9

3 First premolar 9-10

16-20 4 Canine/cuspid 10-13

5 Second premolar 11-12

14-16 6 First molar 5-6

7 Second molar 12-13

20-24 8 Third molar 18-25