LCSC06 Biological Sciences Head & Neck 2 Oral & Pharyngeal Structures Marianne Bos-Clark MSc BA(Hons) MCRSLT HPC mbosclark@marjon.ac.uk

This session Oral & pharyngeal structures Dentition Tongue Taste & Sensation Tonsilar Tissue

Oral & pharyngeal anatomy Cavities of the oropharynx: Oral Nasal Oropharynx, naso- and laryngopharynx Pharynx LESSON 29

The oral cavity Extends from oral opening (lips) to pillars of fauces at back Teeth and alveolar ridge or maxillae make up lateral margins Palpation of oral cavity In pairs Open wide. Torch in non dominant hand: identify faucial pillars and soft palate Say ‘ah’ observe soft palate movement: symmetrical? Look for paletine tonsils between faucial pillars

Dentition Housed in alveolar of maxillae and mandible Function: Mastication Articulatory surface for speech sounds Upper and lower dental arches: equal numbers of teeth Incisors Cuspids Bicuspids Molars Each has root in gingival or gum line Crown is visible 1/3: surface of dental enamel Heart of tooth is pulp: contains nerve supply Have a look Identify incisors Cuspids Bicuspids Molars Bite lightly on molars and hold lips (not teeth) open for an /i/ vowel Use gloved finger to palpate lateral margins of the teeth and gums Use tongue depressor to move cheek away from teeth and examine for occulsion

Dentition

Dentition Zsigmond system Upper right quadrant 87654321 EDCBA Lower right quadrant Upper left quadrant 12345678 ABCDE Lower left quadrant

Dentition

Dentition

Deciduous/ permanent Dentition For development of decidious & permanent dentition, see Atkinson & McHanwell (2002) Basic Medical Science for SLT students. London:Whurr (p308)

The hard palate Rugae Median raphe Soft palate Observe and palpate: Run fingers gently back along hard palate RUGAE: prominent lateral ridges MEDIAN RAPHAE: divides hard palate into equal halves Palpate margin between hard and soft palate

Soft palate Uvula Velum Pillars of fauces Anterior Posterior SOFT PALATE aka VELUM: movable muscle mass separating oral and nasal cavities (orophx and nasophx) Attaches in front to patetine bone-is a muscular extension of the hard palate PILLARS OF FAUCES/FAUCIAL ARCHES: Anterior: aka glossopalatine arch Posterior: aka pharyngopalatine arch With palatine tonsil inbetween

Muscles of the velum Muscle Function Levator veli palatine Elevator *also movement of Eustachian tube Musculus uvulae Elevator/bunching Tensor veli palatine Tenses and shortens Palatoglossus Depressor Palatopharyngeus

The tongue Occupies floor of mouth Functions include: Articulation Mastication Deglutition Etc…

The tongue MEDIAN FIBROUS SEPTUM TIP or APEX BASE OF TONGUE DORSUM TERMINAL SULCUS LINGUAL PAPILLAE LINGUAL TONSILS INFERIOR SURFACE SUBLINGUAL FRENULUM SUBLINGUAL FOLD Observe/palpate and identify in partners mouth: MEDIAN FIBROUS SEPTUM: divides longitudinally: separates L & R: origin of transverse muscles over this MEDIAN SULCUS TIP or APEX: anterior most portion BASE OF TONGUE: resides in oropharynx DORSUM/DORSAL SURFACE: superior surface, mucous membrane covers superior surface. The dorsum (upper surface) of the tongue can be divided into two parts: 1. oral part (anterior two-thirds of the tongue) that lies mostly in the mouth 2. pharyngeal part (posterior third of the tongue), which faces backward to the oropharynx The two parts are separated by a V-shaped groove, which marks the sulcus terminalis (or terminal sulcus). TERMINAL SULCUS: marks posterior surface of tongue (SURROUNDED BY PAPPILLAE) LINGUAL PAPILLAE: aka taste buds: small irregular prominences on surface LINGUAL TONSILS: beneath membranous lining of pharyngeal surface of tongue: groups of lymphoid tissue INFERIOR SURFACE OF TONGUE: rich blood supply under tongue-meds easily absorbed Palpate gently: LINGUAL FRENULUM SUBLINGUAL FRENULUM: band of tissue from inferior tongue to mandible SUBLINGUAL FOLD: transverse band of tissue on either side of tongue: at this point are DUCTS of SUB LINGUAL SALIVARY GLANDS Lateral to lingual frenulum: DUCTS for SUBMANDIBULAR SALIVARY GLANDS: hidden under mucosa on inner surface of mandible

The tongue muscles and movement 1 Intrinsic muscles of the tongue Muscle Location Action CN SUPERIOR LONGDITUDINAL NEAR EPIGLOTTIS-SIDES OF TONGUE WIDENS, THICKENS AND SHORTENS TONGUE TIP AND EDGES XII INFERIOR LONGDITUDINAL HYOID BONE/BASE OF TONGUE-APEX OF TONGUE WIDENS, SHORTENS, CREATES CONVEX DORSUM, DEPRESSES TIP TRANSVERSE TONGUE SEPTUM-MUCOSA AT SIDES OF TONGUE ELONGATES, NARROWS, THICKENS, LIFTS SIDES VERTICAL SUPERIOR SURFACE-INFERIOR SURFACE WIDENS AND FLATTENS TONGUE TIP FINE GRADED MOVEMENTS: CONTROL REQUIRED FOR ARTICULATION

Intrinsic tongue muscles

The tongue muscles and movement 2 Extrinsic muscles of the tongue: Muscle Action CN GENIOGLOSSUS Anterior Posterior MANDIBLE-DORSUM + HYOID Ant. Contraction =retraction. Post. Contractio=protusion XII Hypoglossal HYOGLOSSUS TONGUE-HYOID DEPRESSES AND RETRACTS TONGUE XII PALATOGLOSSUS SOFT PALATE-TONGUE CONTRATION=ELEVATION OF BACK OF TONGUE XI Accessory STYLOGLOSSUS TEMPORAL BONE-SIDES OF TONGUE CONTRACTION=UPWARDS AND BACKWARDS MOVEMENT LARGE TONGUE MOVEMENTS-GENIOGLOSSUS DOMINANT

Extrinsic tongue muscles

Extrinsic tongue muscles

Therapy

Therapy

Therapy

Therapy

The tongue taste and sensation Tip sweet/sour Sides sour & salty Posterior bitter INNERVATION OF TASTE AND SENSATION Sensory innervation of the tongue is different for taste sensation and general sensation. ANTERIOR 2/3 OF TONGUE: general sensations and taste sensations are carried via different nerves. Somatic (TOUCH, PRESSURE, TEMP) sensations travel from the tongue via the TRIGEMINAL NERVE (V) Taste sensation is carried to the FACIAL NERVE (VII) POSTERIOR 1/3 OF TONGUE: more simple innervation, as both taste and general sensations are carried by the GLOSSOPHARYNGEAL NERVE (IX) CENTRAL AREA: SOMATIC SENSATION: CN V

Salivation Salivary glands Parotid Submandibular Sublingual Saliva: two types of saliva SEROUS : thin and watery MUCOIDAL: more viscous/sticky Function of saliva: DIGESTIVE DISINFECTANT ###Error on diagram: submaxillary gland read submandibular Types of saliva Mucoidal: SYMPATHETIC NERVOUS SYSTEM: THICK/STICKY: fight or flight response-staying power Serous: PARASYMPATHETIC NERVOUS SYSTEM: THIN/WATERY: rest and digest Why have two types of saliva? Salivary glands (25%) The parotid is the largest salivary gland and is situated below the ear. The saliva is released through an opening called the parotid duct which enters the mouth on the inside of the cheek next to the upper molar teeth. There is one on each side. Serous saliva-thin and watery. Innervation is through CNIX (glossopharyngeal nerve) (60%) The submandibular salivary gland is situated under the mandible (lower jaw bone) and releases saliva just underneath the front of the tongue, behind the front teeth. There is one on each side. Produce both serous and mucoidal saliva. Secreted through Wharton’s Duct on either side of the frenulum of the tongue. Innervated through branches of CN VII (15%) The sublingual salivary glands are situated under the tongue and release saliva from many small openings (ducts) under the tongue. This pair of salivary glands sit next to each other under the tongue. Produces serous and mucoidal saliva. Innervated by CV VII-facial nerve Approximately one to one and a half litres of saliva is produced every day. If volume falls outside a person’s norm by 50% or more they experience symptoms of dry mouth. Normal healthy adults swallow their saliva approx once or twice per minute If one salivary gland is damaged it is thought some form of homeostatic mechanism will increase the flow of saliva from other glands to compensate: thus keeping production as near normal as possible Function of saliva: Lubrication Moistening food, and helping to create a food bolus, so it can be swallowed easily. Digestion : Contains the enzyme amylase that breaks some starches down into maltose and dextrin. Secretes enzyme: salivary lipaseto start digestion of fats Thus, digestion of food occurs within the mouth, even before food reaches the stomach. Disinfection: A common belief is that saliva contained in the mouth has natural disinfectants, researchers find human saliva contains such antibacterial agents as secretory IgA, lactoferrin, and lactoperoxidase.

Tonsils 1 Palatine tonsils Lingual tonsils Pharyngeal tonsils (adenoids)

Tonsils 2 Name Location Function: Part of limbic system/immune response Believed to be involved in helping fight pharyngeal and URT infection Name Location Adenoids: pharyngeal tonsils Roof of pharynx Palatine tonsils Sides of pharynx between faucial arches Lingual tonsils Behind terminal sulcus (tongue) tonsils are areas of lymphoid tissue Most commonly, the term "tonsils" refers to the palatine tonsils that can be seen in the back of the throat ADENOIDS (also termed "pharyngeal tonsils") located in roof of pharynx PALATINE TONSILS: sides of pharynx between glossopalatine and pharyngopalatine arches (faucial arches) LINGUAL TONSILS : behind terminal sulcus (tongue) Together this set of lymphatic tissue is known as Waldeyer's tonsillar ring

Nasal cavities Nasal septum Turbinates Nares Paranasal air sinuses Note that the roof of the nasal cavity is made up of the cribriform plate (not labelled) but on each side of (1). Also note that the floor of the nasal cavity is made up of the palatine processes of the maxilla (6). Nasal cavity: perpendicular aspect of ethmoid bone and vomer and septal cartilage Divide nasal cavity laterally. NASAL CONCHAE: (nasal turbinates or concha) scroll like bones on lateral surface of nasal cavity Inferior Middle Superior Covered with mucosal layer-rich blood supply Function: warms and humidifies air before it reaches more delicate tissue of resp system Their shape greatly increases surface area of nasal cavity-promoting rapid heat exchange

Paranasal Sinuses Air-filled spaces, communicating with nasal cavity within the bones of the skull and face Function: debated Decrease skull weight Increased vocal resonance Protection Insulation Biological function The biological role of the sinuses is debated, but a number of possible functions have been proposed: Decreasing the relative weight of the front of the skull, and especially the bones of the face. The shape of the facial bones is important, as a point of origin and insertion for the muscles of facial expression. Increasing resonance of the voice. Providing a buffer against blows to the face. Insulating sensitive structures like dental roots and eyes from rapid temperature fluctuations in the nasal cavity. The paranasal sinuses are lined with a mucous membrane that secretes a fluid to keep the lining moist. Under normal conditions, the sinuses drain into various parts of the nasal cavity.

Eustachian tube Location: Function: Connects middle ear with nasopharynx: approx 35mm long Each tube exits m/ear as a narrow, boney canal in the petrous temporal bone As they leave the bone the medial 2/3 of each tube is enclosed by cartilage beneath the bony roof Tensor veli and levator veli palatine are attached to the cartilage and produce tubal elevation where tubes open into nasopharynx Tubes: lined with respiratory epithelium containing mucous glands Functions: allows air into middle ear cavities so air pressure on each side of tympanic membrane can be equalised to prevent distortion or rupture of eardrum caused by excess pressure differentials Also drains mucous from middle ear

The pharynx Divided into areas: Oropharynx Nasopharynx Laryngopharynx The pharynx: the part of the neck and throat situated immediately posterior to the mouth and nasal cavity, and cranial, or superior, to the esophagus, larynx, and trachea. Functions It is part of the digestive system and respiratory system of many organisms. Because both food and air pass through the pharynx, a flap of connective tissue called the epiglottis closes over the trachea when food is swallowed to prevent choking or aspiration. In humans the pharynx is important in vocalization. Parts The human pharynx is conventionally divided into three sections: Oropharynx The oropharynx lies behind the oral cavity. The anterior wall consists of the base of the tongue and the vallecula; the lateral wall is made up of the tonsil, tonsillar fossa, and tonsillar (faucial) pillars; the superior wall consists of the inferior surface of the soft palate and the uvula. Nasopharynx The nasopharynx lies behind the nasal cavity. Postero-superiorly this extends from the level of the junction of the hard and soft palates to the base of skull, laterally to include the fossa of Rosenmuller. The inferior wall consists of the superior surface of the soft palate. Laryngopharynx The laryngopharynx, also known as the hypopharynx, roughly corresponds to the levels between C3 to C6, it includes the pharyngo-esophageal junction (postcricoid area), the piriform sinus, and the posterior pharyngeal wall. Like the oropharynx above it the hypopharynx serves as a passageway for food and air and is lined with a stratified squamous epithelium. It lies directly anterior to the upright epiglottis and extends to the larynx, where the respiratory and digestive pathways diverge. At that point the laryngopharynx is continuous with the esophagus posteriorly. The esophagus conducts food and fluids to the stomach; air enters the larynx anteriorly. During swallowing, food has the "right of way", and air passage temporarily stops.

Pharyngeal muscles Superior pharyngeal constrictor Middle pharyngeal constrictor Inferior pharyngeal constrictors Superior pharyngeal Middle pharyngeal Inferior pharyngeal thyropharyngeal-superior cricopharyngeal-inferior Salpingopharyngeal Stylopharyngeal The salpingopharyngeus muscle arises from the inferior part of the cartilage of the auditory tube in the nasal cavity; it passes downward and blends with the posterior fasciculus of the palatopharyngeus muscle.

Pharyngeal musculature Muscle function Innervation Superior pharyngeal constrictor Velopharyngeal closure Reduces diameter CN XI & X Middle pharyngeal constrictor Inferior pharyngeal constrictor Reduces diameter: Two parts: Cricopharyngeal muscle *arises from cricoid Muscular orifice of oesophagus 2. Thyropharyngeal muscle *arises from thyroid Salpingopharyngeus Elevates lateral pharyngeal wall Stylopharyngeus Elevates pharynx CN IX Vertical tube Muscles wrap horizontally from front to midline point at back. Muscles also run horizontally from skull structures: salpingopharyngeus & stylopharyngeus

The epiglottis Leaf-shaped cartilage Attached to root of tongue Considered part of the larynx: Leaf-shaped elastic cartilage attached below by a narrow stalk of connective tissue to internal surface of the thyroid angle just beneath the internal surface of the thyroid angle just beneath the thyroid notch. Convex lingual surface of the epiglottis faces anteriorly and is separated from the tongue by the valleculae More detail in Larynx lecture? *****NEEDS SOMETHING ABOUT PYRIFORM SINUS’ UES AND UPPER OESOPHAGUS