Oral Cavity

Oral Cavity- It includes the anatomy of oral cavity.
Structure of oral cavity,tongue,sensory and motor nerve supply,It's function, teeth ,hard palate , soft palate, lips,cheeks , gums, oral mucosa, organization of oral mucosa, structure of oral mucosa.

1. ORAL CAVITY Monika Pandarkar Roll.no.-22 Final year B.pharm 01

2. Oral cavity Structure of oral cavity Mouth Teeth Gums Cheeks Lips Palate Tounge Oral mucosa 02

3. Oral cavity(Mouth) The oral cavity, better known as the mouth, is the start of the alimentary canal. It has three major functions: Digestion – receives food, preparing it for digestion in the stomach and small intestine. Communication – modifies the sound produced in the larynx to create a range of sounds. Breathing – acts as an air inlet in addition to the nasal cavity. STRUCTURE Extends from the lips to the oropharyngeal isthmus. The oropharyngeal isthmus: Is the junction of mouth and pharynx. Is bounded: Above by the soft palate and the palatoglossal folds Below by the dorsal of the tounge. 03

4. Structure of oral cavity Oral cavity consists of two parts : A. Oral vestibule Boundaries : 1.Antereriorly by lips 2.laterally by cheeks 3.Posteriourly and medially by teeth and gums B. Oral cavity proper Boundaries : 1.Anteriorly laterally by teeth and gums 2.superiourly by the palate 3.Inferiorly by the tounge and the floor ot the mouth 4.Posteriorly by opening into the pharynx. 04

5. Tongue Mass of striated muscles covered with the mucous membrane. Divided into right and left halves by a median septum Three parts: Oral (anterior 2/3 rd ) Pharyngeal(posterior1/3) Root (base) Two surfaces: Dorsal Ventral 05

6. Sensory and motor nerve supply Sensory nerves: Anterior 2/3: General sensations: Lingual nerve Special sensations : chorda tympani Posterior :. General & special sensations glossopharyngeal nerve Base :. General & special sensations internal laryngeal nerve Motor nreves: Intrinsic muscles: ▪ Hypoglossal nerve Extrinsic muscles:- All supplied by the hypoglossal nerve,except the palatoglossus. The palatoglossus supplied by the pharyngeal plexus 06

7. Functions : The tonge is the most important articulator for speech production. During speech, the tongue can make amazing range of movements. The primary function of the tongue is to provide a mechanism for different areas of the tongue, but are generally found around the edges. They are sensitive to taste. Taste buds are located on four main tastes: Bitter, Sour,Salty & Sweet. 07

8. Teeth The teeth are the hardest substances in the human body. Besides being essential for chewing, the teeth play an important role in speech. Parts of the teeth include: • Enamel: The hardest, white outer part of the  tooth. . Enamel is mostly made of  calcium  phosphate, a rock-hard mineral. • Dentin: A layer underlying the enamel. It is a hard tissue that contains microscopic tubes. When the enamel is damaged, heat  or cold can enter the tooth through these paths and cause sensitivity or pain. • Pulp: The softer, living inner structure of teeth.  Blood  vessels and nerves run through the pulp of the teeth. • Cementum: A layer of connective tissue that binds the roots of the teeth firmly to the gums and jawbone. • Periodontal ligament: Tissue that helps hold the teeth tightly against the jaw. 08

9. A normal adult mouth has 32 teeth, which (except for  wisdom teeth ) have erupted by about age 13: • Incisors (8 total): The middlemost four teeth on the upper and lower jaws. • Canines (4 total): The pointed teeth just outside the incisors. • Premolars (8 total): Teeth between the canines and molars. • Molars (8 total): Flat teeth in the rear of the mouth, best at grinding food. •  Wisdom teeth  or third molars (4 total): These teeth erupt at around age 18, but are often surgically removed to prevent displacement of other teeth. Functions: Mastication Speech Appearance Growth of jaws 09

10. Hard palate The hard palate is the horizontal bony plate that makes a subsection of the  palate  of the mouth. It makes the anterior two-thirds of the roof of the  oral cavit y. The hard palate is made of two facial bones: palatine process of the maxilla and paired palatine bones. Borders: The anterior portion of the palate is bordered anteriorly and laterally by the maxillary  teeth . Superiorly it is covered by the respiratory  epithelium  of the nasa l cavity  and inferiorly by the masticatory epithelium of the  ora l cavity . Posteriorly, the hard palate is connected to the  soft palat e. Functios: Feeding Speech 10

11. Structure : The hard palate separates the oral and nasal cavities . Its bony structure is comprised of three cranial bones, the  maxilla  and the paired  palatine bones . Anteriorly, the palatine process of the maxilla is situated, covering the area between the two sides of the maxillary dental arch . In the anterior midline, the incisive foramen can be found, which sits just below the incisive papilla that is a fleshy convexity on the palatal mucosa . Posterolaterally, one centimeter medial from the second maxillary molar, the greater  and lesser palatine foramina can be found . Deep in the palatal mucosa are hundreds of mucous secreting  salivary glands . 11

12. Soft palate The soft palate, also known as velum, is a mobile fold of soft tissue  attached to the posterior margin of the hard palate  . It extends posteroinferiorly, being leveled with the border between the  nasopharynx and oropharynx . It is distinguished from the hard palate by having a darker red color with a yellowish tone. Lying between the oral and nasal cavities, the soft palate features the oral and nasal surfaces. The oral surface is covered by the  non-keratinized stratified squamous epithelium  with secretory   saliva ry glands. The nasal surface is lined by the simple ciliated columnar epithelium (respiratory epithelium) and it is continuous with the floor of the  nasal cavity. The four borders of the soft palate are the anterosuperior, two lateral, and an inferoposterior border. 12

13. Lips These are two fleshy folds that circumscribe the mouth and closes the cavity. Two Lips Upper Lip and LowerLip The Corner of the mouth where the two lips meet is called Commissure. Two Grooves are distinguished around lips. Nasolabial groove Labiomental groove. FIVE LAYERS 1. Skin-contains hair follicles and sebaceous glands 2. Superficial Fascia- contains some fats 3. Orbicularis Oris muscle - serves as sphincter of the mouth 4. Submucous tissue - contains vessels, mucous labial glands and labial branches offacial artery 5. Mucous membrane - innermost layer 13

14. Cheeks(Buccal mucos a) The cheeks are formed by the buccinator muscle, which is lined internally by the oral mucous membrane. The buccinator muscle contracts to keep food between the teeth when chewing, and is innervated by the buccal branches of the facial nerve (CN VII). It consists of stratified squamous epithelium ,lamina propria and submucosa. Submucosa of cheeks contain fat cells along with lobules of minor salivary glands and muscle fibres. 14

15. Gums(Gingivae) They surround the teeth and cover the upper and lower alveolar ridges. The gingiva is composed of an outer epithelium and an inner network of connective tissue. This outer epithelial layer is keratinized, forming a protective layer around the tooth. Contained within the inner gingival connective tissue are gingival fibroblasts, which play a crucial role in tissue repair and the inflammatory response . 15

16. ORAL MUCOSA Mucous Membrane: Moist lining of the gastrointestinal tract, nasal passages and other body cavities that communicate with the exterior. In the oral cavity the lining is called as oral mucous membrane or oral mucosa. Functions of the Oral Mucosa1: Protection : Barrier for mechanical trauma and microbiological insults. Sensation :Temperature (heat and cold), touch, pain, taste buds, thirst; reflexes such as swallowing, etching, gagging and salivating. Secretion : Salivary secretion. Thermal regulation: Important in dogs not in humans 16

17. Organization of oral mucosa Three types according to FUNCTION: 1. Masticatory Mucosa: 25% of total mucosa. Gingiva (free, attached and interdental) and hard palate. Primary mucosa to be in contact with food during mastication. MASTICATORY MUCOSA IS USUALLY KERATINIZED. 2. Lining Mucosa: 60% of total mucosa. Covers the floor of mouth, ventral (underside) tongue, alveolar mucosa, cheeks, lips and soft palate. Does not function in mastication and therefore has minimal attrition. Non-keratinized; soft and pliable. 3. Specialized Mucosa : 15% of total mucosa. Covers dorsal tongue and composed of cornified epithelial papillae. 17

18. Structure of oral mucosa Oral mucosa consists of two layers, the surface stratified squamous epithelium and the deeper lamina propria   . In keratinized oral mucosa, the epithelium consists of four layers: Stratum basale  (basal layer) Stratum spinosum  (prickle layer) Stratum granulosum  ( granular layer) Stratum corneum   (keratinized layer) In nonkeratinised epithelium, the two deep layers ( basale and  spionosum ) remain the same but the outer layers are termed the  intermediate   and  superficial  layers. Depending on the region of the mouth, the epithelium may be nonkeratinized or keratinized.  18

19. Nonkeratinized squamous epithelium covers the  soft palate , inner lips, inner cheeks, and the floor of the mouth, and ventral surface of the tongue.  Keratinized squamous epithelium is present in the gingiva and hard palate   as well as areas of the dorsal surface of the tongue. The lamina propria is a fibrous connective tissue  layer that consists of a network of  type I  and  III   collagen  and  elastin   fibers in some regions. The main cells of the lamina propria are the  fibroblasts , which are responsible for the production of the fibers as well as the extracellular matrix . A  submucosa  may or may not be present deep in the dense layer of the lamina propria, depending on the region of the oral cavity. If present, the submucosa usually contains loose connective tissue and may also contain adipose tissue  or salivary glands , as well as overlying bone or muscle within the oral cavity. [ Typically, regions such as the cheeks, lips, and parts of the hard palate contain submucosa   (a layer of loose fatty or glandular connective tissue containing the major blood vessels and nerves supplying the mucosa).  A basal lamina is at the interface between the oral epithelium and lamina propria similar to the epidermis and dermis. 19

20. Reference : Human anatomy and physiology Textbook by Ross and Wilson Human anatomy and physiology Textbook by Tortora 20

21. Thank You 21