Mucosa Flashcards
The 2 cell lines of basal cells
2 types of population A. Serrated o has protoplaimc pedicles projecting into the CT
o Healvly packed with tonofimament
o Adapted for attachment
B. Non-serrated o Stem cells (slowy cycling cells)
Basal cells general features
§ Single layer of cub. Cells § Least diffrentiated § Promenant mitotic activity which give rise to ü stem cells go through the cells cycle slowly and produce basal cells
ü Amplyfing cells which increase the number of cells avialable for maturation
§ Active Pr. Synthesis cells ü Tonofilaments aggregate to form tonofiblriles
ü Protein of the basal lamine
stratum germinativum
Deep layers (para-basal layer) can divide and share the same function with the basal cell layer, together they are called
keratinosome
Odland body
lamellar granule
Odland body composition
ü Rich in glycolipids
Granular cells features
Cells are..
o Flatter, Wider, larger & with less organelles o More maturation o Contains more tonofilaments o The nuclei show signs of degeneration & pyknosis.
§ Reduced rates of Pr. Synthesis. Prs such as involucrin & loricrin help to increase the thickness of the cell membrane and forming a resistant cornified cell envelope
Keratohyaline granules ü basophilic granules ü Contains pro-filaggrin
(precursor of the protein filaggrin) which plays an important role in binding keratin filaments together
o Odland body also present in this layer and discharge their content in the intercellular spaces
Para k
Organelles
Cells retain the pyknotic or shrunken nuclei or partially lysed organelles
Results of high turnover of mucosa
Ø Healing of the oral mucsa is faster than healing of the skin Ø Oral ulcers re-epthilialized within 12-15 days Ø Oral wounds heal without scar formation
Turnover rate of mucosa
Keratnized mucosa 40-55 days o Non- keratnized mucosa 25 days
Dodf between k and non k
- no granular cell
- no kerato hyaline granules
- no filaggerin
- smaller membrane coated granules
- tono filaments are less developed
- basal cell is the same
- intermediate cells are larger
Closely packed less prominent junctions - superficial layer contain more organelles and a nucleus
Melanocytes
Long, living cells, selfreplicating
Contact with 30–40 keratinocytes
Langerhan cell
Under the influence of chemokines by the keratinocytes
Present In the upper layer of oral epithelium
E\m vacuolated nucleus
Has a characteristic rod- or flask-shaped granules
Peptides are transferred and presented to the tlymphocytes either in the lamina propria or at the regional lymph nodes
Merkel cell
Derived from the neural crest
Contains Keratin filaments &desmosomes
Do not appear as clear cells
Nucleus shows deep invagination (rodlet appearance)
Most seen in masticatory mucosa
Lymphocyte
Closely associated with the
langerhans cells
Transient, present only in case of inflammation
do not reproduce themselves in epithelium
Basement membrane
oIt is 1 to 4 µm thick and it includes the reticular fibers & anchoring fibers
o it is relatively cell free. oThis zone stains positively with the
periodic acid-schiff (pas) method Ø Indicating that it contains neutral mucopolysaccharides (glycosaminoglycans).
Lamina densa and lucida
Made up of A. clear zone (lamina lucida) Ø20–40 nm wide glycoprotein layer Ø contains type IV collagen
B. dark zone (lamina densa)
Ø contain laminin and bullous pemphigoid antigen
Additional one function if BM
promote differentiation, peripheral nerve regeneration and growth
Ratios of fibers of lamina propria
Collagen type 1 90%
Type 3 8%
With elastic fibers
Function of rougea area
It plays a part in speech o During denture processing it function as secondary stress bearing area
o In fronsic dentistry, it can be used to idinitfy individulas as it is unique like fingure prints
Muco ging line in palate?
• On the palate, there is no sharp distinction between the gingiva and the peripheral palatal mucosa
type of K of gingiva
q Para-keratinized 75% q Ortho- keratinized 15% q Non-keratinized 10%
Free ging width
0.5 to 1.5
Sulcus depth in various occasions
It is under absolute normal conditions or Germfree animals, its depth is about 0 mm
• In normal healthy individuals, the depth of gingival sulcus is 1.8 to 2 mm.
Inflammatory cells and sulcular epithelium
It is lined by non- keratinized epithelium that permit some inflammatory cells
Attached gingival width
Width of the attached gingiva in incisors region is 3.5-4.5mm & in the premolar region is 1.9 mm
Attached ging is wider in …
ü The width of attached gingiva increase with age and in super-erupted teeth
Factors affecting stippling
- More buccal than lingual
- more in males
- absent in infants and old age
- inflammation
Terminology of parts of interdental gingiva
The depression in gingiva forms vertical folds called interdental grooves
o Col In between the buccal and lingual peaks of interdental gingiva
Incision in musticatory mucosa?
Incisional wound doesn’t create gap
Vestibular mucosa
The mucosa of the vestibule is thin, non-keratinized
o Loosely textured allowing free movement of the cheek and lips.
o Median and lateral labial fermium are folds of mucous membrane contains C.T without muscles fibers
Taste buds number in fungiform
1to3
N. of circumvallate papilla
8 to 12
Inner supporting cells of taste buds
Inner supporting cells are shorter ones are spindle shaped.
Number and shape of receptor cell
4-20 cells.. receptors of taste stimuli
Cells are darker & more slender but thickened at middle Hair like process extend into the gustatory pore without reaching its outlet
Zones of lip
Skin
Vermilion zone
Intermediate zone
Labial mucosa
Definition of suckling pad
In infants the intermediate zone is thickened and
appears white, which represents an adaptation to suckling called the suckling pad.
Vermilion border age change
In young people this border is demarcated sharply, but as a person is exposed to ultraviolet radiation, the border becomes diffuse and poorly defined.
Mucogingival junction clinical identification
This junction is identified clinically by Ø A slight indentation called the mucogingival
Junctional epi histology
Ø Epithelium.. q Nonk. St. sq. epith. q Basal cell layer I. Single layer of cuboidal cells II. Attached to each other by desmosomes & to the basal lamina by hemi-desmosomes.
q Supra-basal and superficial cells a) Polyhedral and become spindle or flattened at the tooth surface.
b) Obliquely directed to reach tooth surface parallel to it.
c) The cells form 3-4 layers apically and increased to 15-30 layers coronally.
d) Prominent intercellular spaces.
Ø Basal lamina.. q External basal lamina i. Regular basal lamina formed of lamina lucida and lamina densa.
ii. Interface the lamina propria of the gingiva iii. Basal cell layer resting on the external basal lamina
q Internal basal lamina i. Binds to hard tissue ii. Supra-basal cells resting on the internal basal lamina
iii. It attachs the gingiva to the tooth
Ø Lamina propria.. q Less collagen fibers q Contains inflammatory cells.
Properties of j.e cells
-high turn over rate 2to 6 days
-rapid division
- large inter cellular spaces
Contain macrophages lymphocytes and plasma cells
-Less desmosomes and tonofilaments
- no rete pegs
- large cytoplasm with prominent golgi and rer
Zones of j.e
Junctional epithelium is divided into three zones
- Coronal zone is highly semipermeable and allows entry of toxins and passage of gingival fluid into the sulcus.
- Middle zone is an adhesive zone (Attachment epithelium).
- Apical zone has a proliferative capacity to replace shaded cells of the junctional epithelium.
Integrity of the dento-gingival junction
function
- Acts as a barrier against plaque bacteria
- Allow the following to gain access to the gingival margin o Gingival fluids o Inflammatory cells o Immune host defense
- High rate of turn over o Fast repair
Primary and secondary attachment epi
and once the tip of crown erupt the REE is called primary attachment epith
When the REE has disappeared, the primary attachment epithelium is replaced by a secondary attachment epithelium
Features of stage 3 of djg shift
q This is not a passive manifestation. The epithelium keeps shifting along tooth surface, and no longer remains at the CEJ
q This is a slow and not a continuous process, which is an effort by the body to maintain the integrity of the dento-gingival junction
Time frame of stage 1 and 2
1—- up till final year of primary teeth life and for permanent in 20 to 30 y
2—- 40 years
3— non continuous but slow process of shift for maintaining integrity of epi.j
4 —- pathological
Clinical age changes
- less saliva
- vermilion border less distinct
- cracking in commissure
- loss of tongue papilla
- loss of stippling
- lingual varicose
- decrease ability to repair
Histologoical changes
oDecreased Number & thickness of rete ridges oDecreased Mitotic activity oDecreased Degree of keratinization oDecreased Resiliency
qTurnover gets longer q Thickening of collagen bundles
