STOMATOGNATHIC SYSTEM

DEFINITION OF TERMS:

PHYSIOLOGY – is the science which deals with the study of normal

tissue functions of a normal living body.

GENERAL PHYSIOLOGY – deals with the study of basic activities of living organisms as a whole, emphasizing on function and dynamic changes occurring within cells, tissues and blood vessels.

ORAL PHYSIOLOGY – a branch of Gen. Physiology which focuses on the

functions of the different parts in the oral cavity as well as its associated structures. It deals with the Masticatory Apparatus (All structures & organs involved in mastication.)

STOMATOGNATHIC SYSTEM – is a system that comprises of a

highly coordinated structure comprising the human masticatory apparatus.

STOMATOGNATHIC SYSTEM – is a system composed of several

parts capable of acting as a single unit for the processes of:○1. mastication○2. deglutition○3. phonation○4. respiration○5. other behavioral characteristics

or activities

Group of structures that comprises the Stomatognathic System:1. Dental Group2. Osseous Group3. Receptor Group4. Muscular Group5. Salivary Glands6. Organs of the Digestive System7. Organs of the Respiratory System

DEVELOPMENT OF THE ORAL CAVITY:

>ORAL STOMODEUM is the primitive oral cavity that begins to develop at 3 ½ weeks of fetal life.

>It is lined with an ectoderm and unites with the endoderm to form the buccopharyngeal membrane.

ORAL STOMODEUM (3 ½ WEEKS Human Embryo)

>At about 27 days this membrane raptures and the stomodeum establishes a connection with the foregut (future digestive tract).

>At 6 weeks old, the first sign of tooth development is seen.

> The oral ectoderm will give rise to the oral epithelium that runs along the outline of the future dental arches, which is called the DENTAL LAMINA (invagination that forms 2 thicker bands; vestibular lamina & dental lamina).

> Simultaneous with the differentiation of the dental lamina, there arises round or ovoid swellings at 10 different points in each jaw, corresponding to the future position of the deciduous dentition (TOOTH BUDS) .

Dental Lamina

Tooth bud

Enamel Organ - enamel

Dental Papilla - dentin & pulp

Dental Sac - cementum, periodontal ligament & alveolar bone

ORAL CAVITY – is the first portion of the alimentary canal or digestive tract.

Boundaries:1. Anteriorly – Lips2. Laterally – Cheeks3. Superiorly – Hard &

Soft Palate4. Inferiorly – Floor of

the Mouth & Tongue

Divisions of the Oral Cavity:A. Vestibule – smaller,

outer portion

Boundaries:○ 1. Antero-laterally –

lips & cheeks○ 2. Postero-medially –

gums & teeth○ 3. Superior & Inferiorly –

mucous membrane from the lips & cheeks to the gums

B. Oral Cavity Proper – larger, inner portion

Boundaries:○ 1. Antero-laterally –

alveolar arches with their teeth

○ 2. Superiorly – hard & soft palate

○ 3. Inferiorly – tongue & mucous membrane from the side of the tongue to the gums

PARTS OF THE ORAL CAVITY:

A. LipsB. CheeksC. PalateD. Floor of the mouthE. Tongue

A. LIPS

> Two mobile folds that encircle the rima oris.

*Rima/ Orbicularis oris - sphincter muscle of the mouth.

> Covered by skin on its external surface & mucous membrane on its internal surface.

> Parts: 1. Angle of the mouth

– points where the upper & lower lips meet at the sides.

2. Naso-labial groove – from the side of the nose to the

angle of the mouth.

3. Mento-labial groove – between the

chin & lower lip.

4. Philtrum – from the

inferior border of the nose to the upper lip.

5. Frenulum of the upper & lower lips

– vertical mucous folds found on the internal surface of the lips connecting them to the gums.

> Composed of the following layers:

1. Skin2. Superficial Fascia3. Orbicularis oris Muscle4. Submucous Layer5. Mucous Membrane

> Supplied by the following:

Nerve:1. Infra-orbital Nerve – from the maxillary

nerve & supplies the upper lip2. Mental Nerve – from the mandibular

nerve & supplies the lower lip

Blood:1. Superior Labial Artery2. Inferior Labial Artery

B. CHEEKS

> Forms the lateral boundary of the vestibule of the mouth.

> Buccinator muscle is the major muscle that makes up the cheeks.

> Composed of the following:

1. Skin2. Superficial Fascia3. Buccopharyngeal Fascia4. Buccinator Muscle5. Submucous Layer6. Mucous Membrane

C. PALATE

> Forms the roof of the mouth separating the nasal cavity & the nasopharynx from the buccal cavity.

> Divided into 2 parts:

1. Hard palate – larger, anterior 2/3

2. Soft Palate – smaller, posterior 1/3

1. HARD PALATE

> Formed by the palatine processes of the maxilla & the horizontal plates of the palatine bones.

> The surface is covered by the mucous membrane & periosteum.

> The inferior surface is thicker & its posterior part contain the blood vessels, nerves & mucous glands.

> Presents the following:

1. Median Raphe – longitudinal ridge extending from the uvula to the incisive papilla.

2. Incisive Papilla – small projection

of the mucous membrane which lies behind the central incisor indicating the location of the opening of the incisive foramen.

- It forms the anterior limit of the median raphe.

(Clinical significance: site of puncture for nasopalatine block injection)

3. Transverse Palatine Ridges or Rugae – is about 3 to 4 distinct elevations crossing the anterior part of the palate.

4. Fovea Palatinae – constant pits

found on the posterior end of the palate, near the midline, that are formed by a coalescence of several mucous gland ducts.

(Clinical significance: These pits are close to the vibrating line which makes them an ideal guide for the location of the posterior border of the denture.)

2. SOFT PALATE

> A soft, flexible mass attached to the posterior end of the hard palate.

> Composed of folds of mucous membrane.

> Presents the following:

1. Uvula – a conical process on the midline of the

posterior border of the soft palate.

2. Palatine Arches or Velum – free margin of the soft palate extending laterally from the uvula that splits as they approach the lateral walls. The split portion forms the pillars of the soft palate.

3. Palatoglossal Arch – anterior pillar of the fauces or anterior palatine arch, encloses the palatoglossal muscle

4.Palatopharyngeal Arch – larger, posterior pillar of the fauces or posterior palatine arch, encloses the palato-pharyngeal muscle.

5. Isthmus of the Fauces or Tonsillar Sinus – an interval between the anterior & posterior pillars. It is triangular in shape & encloses the palatine tonsils.

6. Isthmus of the Pharynx – interval between the free margin of the soft palate & the posterior pharyngeal wall separating the nasopharynx from the lower pharynx.

> Consists of the following: 1. Palatal Aponeurosis 2. Mucous glands 3. Muscles

A. Levator Palati MuscleB. Tensor Palati MuscleC. Palatoglossus MuscleD. Palatopharyngeal MuscleE. Uvulae Muscle

> Supplied by the following:Nerve:

1. Vagus Nerve 2. Accessory Nerve 3. Mandibular Nerve4. Glossopharyngeal Nerve

Blood:1. Greater Palatine Artery 2. Lesser Palatine Artery

D. FLOOR OF THE MOUTH

> Formed chiefly by the mylohyoid muscle & other structures which lie beneath the 2 halves of the body of the mandible.

> Presents the following:

1. Frenulum Linguae or Lingual Frenum – median fold of mucous membrane

extending from the floor of the

mouth to the inferior surface or the tongue.

2. Sublingual Fold – seen on the side of the tongue where the ducts of the sublingual salivary gland is located.

3. Sublingual Papilla – slight

elevation on the anterior end of the sublingual fold indicating the opening of the submandibular ducts.

4. Fimbriated Fold – fold of mucous membrane lying lateral to the frenulum.

E. TONGUE

> A movable mass of muscle covered with mucous membrane lying on the floor of the mouth & associated with the functions of taste, chewing, swallowing & speaking.

> Parts:

1. Root – lower, posterior portion through which the extrinsic muscles, blood vessels & nerves are connected with the organ.

2. Body – anterior, larger portion made up of interlacing skeletal muscles.

3. Margins – lateral sides of the

organ, free & blunt in relation to the gums & teeth.

4. Tip/Apex – pointed & free anterior end, directed

anteriorly against the incisor teeth. It is blunt & rounded when the tongue is at rest.

5. Dorsum Linguae – slightly convex anteroposteriorly. It is divided by a

V-shaped groove called Sulcus Terminalis into;

A. Anterior 2/3 – where lingual papilla are found.

B. Posterior 1/3 – where lingual tonsils are located.

> Lingual papillae – consists of 3 kinds:

A. Vallate/Circumvallate papilla – 10 to 12 per human tongue

B. Fungiform papilla – scattered in between filiform papilla

C. Filiform papilla – most numerous & distributed in rows

> Muscles of the tongue: A. Extrinsic Muscles – originate from

the outside of the tongue. These functions to change the position

as well as the shape of the tongue. 1. Genioglossus 2. Hyoglossus 3. Styloglossus 4. Palatoglossus 5. Chondroglossus

Nerve supply: 1. Hypoglossal Nerve 2. Spinal Accessory Nerve

B. Intrinsic Muscles – are confined within the substance of the tongue & capable only of changing the shape. 1. Inferior Longitudinal 2. Superior Longitudinal 3. Transverse 4. Vertical

Nerve supply: 1. Hypoglossal Nerve 2. Lingual Nerve 3. Glossopharyngeal 4. Chorda Tympani

Blood supply: 1. Lingual Artery 2. Tonsillar Artery