Oral Cavity and Tongue Anatomy PDF

ILOS 1.Describe the LM structure of lips, checks, tongue, pharynx. Oral Cavity and 2.Relate the structure of different components of oral cavity to their function. Tong...

ILOS 1.Describe the LM structure of lips, checks, tongue, pharynx. Oral Cavity and 2.Relate the structure of different components of oral cavity to their function. Tongue 3.Draw a section in the tongue. PRESENTED BY,CLASS 9A UNDER SUPERVISION OF DR Ereny Fekry Understanding Oral Oral mucosa Cavity: Types of oral mucosa: A- Masticatory: The oral cavity: is lined with non- keratinized stratified covers gum, hard palate & dorsum of tongue, squamous epithelium, attached underlying tissues, stratified squamous Connective tissue and minor epithelium with variable degree of keratinization salivary gland are present under the epithelium. B- Lining mucosa: elsewhere in oral cavity, non It consisted of: keratinized stratified squamous epithelium. 1-vestibule. 2-oral cavity proper C- Specialized mucosa: taste buds. LIPS CHEEK Guard the entrance into the oral cavity Its Core of skeletal muscle fibers Composed of 3 regions a - Lined by mucous membrane External aspect: thin skin str. sq. ker. from inside (non. ker. str.) with epithelium. Internal aspect: str. sq. non-ker.& CT , underlying CT, with mucous mucous minor salivary glands. glands. Vermilion zone: thin skin, pink region - Covered outside by (ker. str. sq.) (capillary loops are closed to the with underlying striated muscles. surface), no glands, no hair follicles. Teeth GUMS 20 deciduous (milk teeth), replaced by 32 permanent (adult teeth) Apparent crown & embedded root Histological parts: keratinized epithelium with underlying dense irregular CT, type I collagen. Enamel: hard outer layer that protects Mucous membranes are firmly adherent the tooth, which is highly mineralized. to the periosteum of the alveolar bone. Dentin: It protects the inner core and has tubes that connect to the nerves. Pulp: rich vascular & innervated CT core. Cementum: overlies dentin of the roots.  PALATE HARD PALATE The palate forms the roof The hard palate has a nasal and an oral surface. of the mouth and separates oral and nasal The oral surface:: cavities. Covered with stratified squamous keratinized epithelium that forms The anterior part is the hard palate (its core is deep invaginations, known as rete bone). ridges, which connect closely with the underlying connective tissue. The posterior part is the EP. Epithelium. soft palate (its core is RR. Rete ridges. skeletal muscle). CF. Collagen fiber bundles. CT. Connective tissue HARD PALATE CONT SOFT PALATE The nasal surface: It's the posterior part of the palate, and its Core is composed of skeletal Covered with ciliated pseudostratified muscle. columnar epithelium The oral surface is covered by thin Additionally, the hard palate contains layer of non - keratinized stratified significant amounts of adipose tissue and squamous epithelium. mucous glands. The nasal surface is covered by ciliated pseudostratified columnar epithelium. SOFT PALATE CONT. SOFT PALATE CONT Uvula Its Skeletal muscle fibers (Like uvula) provide functions: the back of the soft palate. Swallowing. Breathing. Speech. and mucous glands. Numerous, mucous glands: are embedded in (Mucous Glands) the core, secreting mucus into oral cavity to Its functions as same as the whole soft palate maintain it moist. functions plus : It Secretes mucus to keep the throat moist ANATOMY OF TONGUE CONT. ANATOMY OF TONGUE The tongue is a pink, muscular organ DORSAL SURFACE: located within the oral cavity proper. It is divided by the gustatory line It is covered by oral mucosa. (sulcus terminalis) into Ant. 2/3 and It is kept moist by the products of the post. 1/3. major and minor salivary glands. Ant. 2/3: irregular due to the presence of Surfaces of the tongue: small projections called papillae. Dorsal surface.(upper) Post. 1/3: irregular due to the presence Ventral surface.(lower) of lymphoid tissues called the lingual 2 lateral surfaces. tonsils. partially keratinized stratified squamous epithelium.  movements of extrinsic and intrinsic muscles of tongue 2. skeletal muscle fibers can be ANATOMY OF TONGUE CONT. classified into : VENTRAL SURFACE: smooth, don't contain any A) extrinsic: papillae. Control in the Tongue position , It moves the tongue (in, out, from side to side). The lingual glands (which are mixed seromucous glands) are embedded in the ventral portion of B) intrinsic: the muscles of the tongue. 3 Its fibers run in different directions: Its mucosa: Str.sq. non-ker. epithelium. longitudinal (sup. & inf.), vertical, lamina propria of CT, which transverse It alters the shape of the contain groups of mucous tongue. glands called lingual glands. LINGUAL PAPILLAE Filiform papillae Number: most numerous. Definition: elevations on the anterior 2/3 of the dorsal surface of the tongue Distribution: arranged in rows, parallel to the gustatory line over the anterior 2/3 of the dorsal surface of the tongue. Function: increase the surface area of the mucosa coming in contact with the food. Shape: conical with Antero posterior inclination. Structure: Epithelium: Lightly keratinized stratified C.T core covered by stra.sq.epith squamous epithelium. (with variable degree of keratinization). Taste buds: absent. core may projects to indent the epithelium to form secondary papillae. Secondary papillae: short or absent  Fungiform Papillae Circumvallate Papillae Are much larger than the fungiform and filiform Number: few. papillae. Epithelium: Covered with st. sq. non ker. at lateral border (dorsum may have some keratinization Distribution: scattered among the filiform papillae secondary papillae: short. especially on the dorsum of the tongue. Number:-8-12 circumvallate papillae. Shape: mushroom shaped, have vascular connective Site: are located in the posterior region of the tongue tissue core(seen as red spots in the fresh state). (in front of the terminalis sulcus). Shape:- Taste buds: few, present in the apical part of the 1- Triangular shape, seen by the naked eye. papilla. 2- It is surrounded by a trench where ducts of von Ebner's gland's located in connective tissue. Secondary papillae: short Taste buds:- Oval shape, and located in the epithelium of the lateral surfaces of the circumvallate papillae. Von Ebner's Glands Foliate Papillae Definition: serous lingual salivary glands. Site :- in connective tissue encircling each Are well developed in some animals and circumvallate papillae. neonates but are poorly developed in Ducts:- open at the bottom of the tranches adults. surrounding these papillae. secondary papillae: long. Function:- 1. Their secretion dissolves the food particles to Site:- posterolateral sides of the tongue. facilitate perception of taste. 2. The flow of secretion washes away food Taste buds:- numerous, present along the particles around the taste buds so, they can sides of the papillae. receive new taste stimulus. 3. The secretion contains lipase enzyme which prevents formation of hydrophobic layer  TEST BUDS TEST BUDS CONT Types of cells in taste bud Neuroepithelial structures 1- Neuroepithelial (gustatory) cells: specialized for perception of taste Spindle in shape pale nuclei, with apical microvilli sensation (gustatory hairs) which extend to the taste pores. embedded within the epithelium of The gustatory hairs are stimulated by food dissolved in saliva the lingual papillae (few is present bases are associated with the afferent nerve fibers. within the epithelium of the palate , epiglottis and pharynx). 2- Supporting cells: They are spindle in shape dark nuclei pale & oval structures(onion Have long microvilli which project into taste pore shaped), connected to the surface of Support and nutrition to gustatory cells the epithelium by a small opening Secrete special secretion in the taste pores to called the taste pore (gustatory facilitate the process of taste sensation. pore). 3-Intermediate cells (type III). 4-basal cells: it is a pyramidal, small undifferentiated cells(stem taste stimulus: cell), it can differentiate to other types of cells: A) location: found between the bases of other cells. 1) salty behind the tip of the tongue B) function: it can divide and renew other cells, it 2) sweet at the tip of the tongue renew gustatory cell every 10 days. 3) sour at the lateral margins of tongue 4) bitter at the back of tongue  PHARYNX Nasopharynx: Epithelium: Lined with Pharynx is conventionally divided psed.str.cili.col.epithelium, which includes into three sections: goblet cells that secrete mucus. 1-Nasopharynx 2-Oropharynx Oropharynx: 3-Laryngopharynx Epithelium: Lined with non-keratinized stratified squamous epithelium, which protects against abrasion from food. Laryngopharynx: Epithelium: Also lined with non-keratinized stratified squamous epithelium.