Digestive System Anatomy: Mouth and Oral Cavity

Digestive System Anatomy

• Includes the mouth, oral cavity (with accessory structures like salivary glands), and pharynx.

Mouth (Os s. Stoma)

• Lips are the Labia oris.
• The Oral cavity is the Cavum oris.
• Accessory structures include the Teeth (Dentes), Palate (Palatum), Tongue (Lingua), and Salivary glands (Gll. salivariae).

Lips (Labia Oris)

• Composed of skin, muscle, tendon, glands, and oral mucosa.
• Labium superius et inferius refers to the upper and lower lips.
• The Rima oris is the mouth opening/slit between the lips.
• Commissura labiorum is where the 2 lips meet.
• Bucca is the cheek, including the m.buccinator, salivary glands, and loose mucosa.
• Horse (eq): Highly mobile lips with a large upper lip covered in fine, sensitive hair, used for collecting food.
• Cow (bo): Has a nasolabial plate (planum nasolabiale) which is a thick, modified skin.
• Carnivores (Car) and smal ruminants (cap;ov): Feature a medial groove (philtrum) in the labium superius.
• Additionally (ca), Papillae labiales are found on the margin of the lower lip.
• Pig (su): Has a rostral plate (disc) or planum rostrale, which consists of the labium superius and rostrum. They are not very mobile, with a short, pointed lower lip covered by upper lip.

Oral Cavity (Cavum Oris)

• Includes the vestibule and the proper oral cavity.
• VESTIBULE (Vestibulum oris):
  • Labial vestibule (vestibulum labiale): Space between the teeth and lips.
  • Buccal vestibule (vestibulum buccale): Space between the teeth and cheeks.
• PROPER ORAL CAVITY (Cavum oris proprium):
  • Limited caudally by the Arcus palatoglossus.
  • Contains the palate (palatum), teeth (dentes), tongue (lingua), and salivary glands.
• The inner surface of the lips and cheeks in ruminants (Ru) has large, backward-pointing papillae.
  • Papillae labiales are most prominent toward the corners of the mouth.
  • Papillae buccales are also present.
• Mucous membrane lines oral cavity.
  • Composed of stratified squamous epithelium.
  • Usually pink, may be pigmented black and contains mixed glands
• Gum (gingiva) is modified mucous membrane attached to teeth and alveolar bone.

Palate (Palatum)

• Partly osseous, partly soft tissue partition separating digestive and respiratory passages.
• Hard palate (Palatum durum) is supported by bone
  • Osseous part: proc. palatinus of os maxilla and os incisive + horizontal plate of os palatinum.
• Soft palate (Palatum molle or Velum palatinum) is the caudal part of the palate.
• The oral side has thick, cornified mucosa.
• Structures of the Palate (eq):
  • Papilla incisiva: Incisive papilla marking the rostral end of the palatine raphe.
  • Rugae palatinae: Palatine ridges (paired), transverse ridges decreasing in prominence. Number of ridges = 14-16 in horses.
  • Raphe palati: Palatine raphe is the median line where the halves of the palate join.
  • Contains also Epiglottis and Palatum molle (6)
• bo has 16-18 rugaepalatine+ with papillae, directed caudally.
• Car, palatine raphe is indistinct:
  • Palatine ridges: ca: 9-10: fe: 7-9
• Soft palate caudally continues the hard palate.
  • A musculomucosal fold (flap) that rostrally attaches to the palatine skeleton
  • Follows the root contours of the tongue when in repose/

(Lingua)

• Ventral part of the oral cavity.
• Composed of striated musculature, connective tissue, adipose tissue, and some glands. Outer layer is thick mucous membrane.
• M. lingualis proprius (intrinsic):
  • Fibrae longitudinales superficiales et profundae (eq)
  • Fibrae transversae
  • Fibrae perpendiculares
• The mucous membrane presents numerous papillae.
  • Mechanical papillae (papillae mechanicae): provide physical texture
    • Filiform papillae (papillae filiformes) are absent in (eq).
    • **Conical papillae (papillae conicae) ​
    • Lenticular papillae (papillae lentiformes)
  • Gustatory papillae (papillae gustatoriae): bear taste buds (gustatory cells, supporting cells, and nerve endings)​
    • Fungiform papillae (papillae fungiformes)
    • Vallate papillae (papillae vallatae)
    • Foliate papillae (papillae foliatae), which are absent in Ruminants Ru.
• The parts of the tongue include:
  • Radix linguae, the root connected to the hyoid bone.
  • Corpus linguae, the body with the dorsum which is apposite the palate. It also contains the mucosal fold by the frenulum linguae.
  • Apex linguae, the free rostral tip.
• Ruminant tongues (Ru) have:
  • Torus linguae: Raised caudal part of the dorsum with large prominence
  • Fossa linguae: Deep pit rostral to the torus
  • p. filiformes: on the dorsum rostral to the fosa (+p.conice+p. lenticular); on the apex.
• ** p. fungiformes**: numerous along the edges of the apex
• Horse's eq tongue:
  • Long, narrow, tall, has tall lateral surfaces
  • dorsum elevated/ slender bar of cartilage - cartilago dorsi linguae
  • Apex is long and spatular is the front
  • Single lingual frenulum- well developted
• Pig tongues Su:
  • Narrow, low dorsum
  • Long, pointed Apex
  • Double lingual frenulum -[1] p. filiformes -[2] p. fungiformes – over dorsal, lateral surface -[3] p. vallatae - 1 pair – at junction of body and root -[4] p. foliatae - 1 pair
• Dog's ca - Highly mobile with a wide/flat Apex withlyssa within the ventral surface - sharp borders+ Sulcus medianus linguae -[1] p. filiformes – soft -[2] p. fungiformes – 1mm in diameter, have very large taste buds -[3] p. vallatae - 2-3 pairs -[4] p. foliatae - 1 pair;extrimly small
• Cat tonsue fe: - caudally directed p. filformes - Vallate - 2-3 pairs - Fungifromes-1mm, large taste buds

Other Oral Structures

• Lyssa: A medial rod-like structure in the submucosa within the apex ventral surface composed of adipose tissue, skeletal muscle, and cartilage
• The sublingual Floor ca:
  • Recessus sublingualis lateralis
  • caruncula sublingualis
  • Frenulum Linguae
• caruncula sublingualis = sublingual caruncle (flattened projection on either side of the frenulum - absent in pigs
• Caruncular fold plica sublingualis lateral to frenulum lingue (horse)
• Lateral sublingual recess (recessus sublingualis lateralis) extends between tongue and mandible.

Tooth Anatomy

• Corona dentis: The free part that projects from the gingiva.
• Cervix dentis: Constriction between the crown and root.
• Radix dentis: The root, concealed by the gingiva and alveolus, not covered by enamel.
• Gingiva surrounds the teeth.
• Enamelum is the outermost layer.
• Dentinum is the main part of teeth substance.
• Cementum is bone-like substance.
• Pulpa dentis is the pulp.
• Tooth surfaces include mesial, distal, lingual, and vestibular (labial or buccal)
• Dentes decidui are deciduous teeth
• Dentes permanentes are permanent teeth.
• Types of Teeth:
  • Incisors (dentes incisivi).
  • Canines (dentes canini).
  • Premolars (dentes premolares)
  • Molars (dentes molares).
• Dental Formula describes number/ classification of teeth, abbreviated followed by number of each teeth on upper/lower
• X2 = number of teeth.
• Pig su: I 3/3, C 1/1, P 4/4, M 3/3 = 44 total teeth.
• Dog ca: I 3/3, C 1/1, P 4/4, M 2/3 = 42 total teeth.
  • Upper P4 and lower M1 are dentes sectorii for shearing flesh and bone.
• Cat: f. I 3/3 C 1/1 P 3/2 M 1/1- 30 teeth Upper P4/ Lower Ml: sectorial carnassial teeth/ dentes sectorii
• Horse eq: I 3/3 C 1(0)/1(0) P 3/3 M 3/3 =40 (or 36) total teeth
  • Canine teeth frequently absent or rudimentary in females/ some mares
    • May have wolf teeth

Horse teeth/ cement

- Horse *eq*- brown teeth/ cement covers entire tooth
- cement-filled infundibula i.e. cups of incisors - Infundibulum dentis (1)
 - folding in M (upper) results in the formation of cement -filled folds of cheek teeth (2).

• Wide gap/ diastema. separates sheep’s incisors from cheek teeth

Salivary Glands

• Small Salivary Glands (gll. salivariae minores): Provide moisture.
  • Labial (gll. labiales)
  • Buccal (gll. buccales)
  • Zygomatic (In carnivores/gl. zygomatica)
  • Molar (In cats/gll. malares)
  • Hard Palatine (gll. palatinae)
  • Lingual (gll. linguales)
• Large Salivary Glands (gll. salivariae majores): Located at a distance from the oral cavity.
  • Parotid (gl..parotis)
  • Mandibular (gl. mandibularis)
  • Sublingual (gll. sublinguales)
  • gl.sublingualis monostomatica
  • gl.sublingualis polystomatica
• Parotid Gland located at junction of the head and neck, ventral to cartilage/ retro-mandibular fossa -->Duches parotideus= opens into oral vestibule top of the a small papilla at opposite=3ed to 5thcheek species: - Dogs= opposite to upper 3rd cheek tooth - Horses= 3rd: Pigs/small Ru= < 3rd/4" Ox= 5th
• Mandibular Grand location=Close angle of jaw/ Partially covered by the gl. parotid/ larger that late in dog, cat/ large Ru --> Duches Mandibularis>caruncula subtíngualis.
• Sullingual Glands lays under mucusa if the latera sublingual recess and lateral surface of the tongue; Duches sublingual is Major>Carruncula subtíngualis

Salivary Glands locations

-Ox bo-Duches parotideus (M2)/ Cap (P3-4)

• Hose eq-Opposite upper P3 gl subtinguailis Poly stomatica
• Pigs -opposte uooee P3
• Dogs -* ca*Opposite upper P3- P4

Pharynx

• Pharynx is a funnel-shaped, musculo-membranous chamber common to the digestive and respiratory tracts.
• Tubular organ
• It has a Tunica mucosa which is the:
  • Respiratory region made of Pseudostratified columnar epithelium.
  • Digestive region whichis Stratified squamous epithelium.
• Pharyneal Cavity (Cavum pharyngis) consists of:
  • Pars nasalis pharingis (dorsal to the soft palate)
  • Pars oralis pharingis (ventral to the soft palate)
  • Pars laryngea pharingis (dorsal to the larynx and leading into the esophagus)
• Cavum pharyngis contains 7 openings, including:
  • Choanae (2 of them)
  • Opharingem tubae auditvae(2)
• Isthmus of faucium divides oral cavity/ pharynx; except during swallowing

Avian mouth anatomy

• Lips and teeth are absent; their functions are met by the edges of the beak
• Horny beak - it varies tremendously in form / diet
  • The tongue: small. triangular, or U-shaped; rigid; inflexible
• Dorsal surface of chicken tongue- smooth and pink + a row of large papillae near the caudal attachment of the tongue
• Duck/Goose has papillae e that fit loosely into grooves in the edges of the beak, which provides a means of sifting water particles
• absent soft palete ==Oropharynx=* combined cavity from beak esophagus+

The Avian glands

  -Rostral manbiular
   - Maxillary
   - Lateral palatine
   - Medial Palatine
      > Glândula Anguli ORIS= with opening
    -- Cauding-Maudioular

• -- Sphesoptery gold

Overview of the anatomy of the digestive system, focusing on the mouth and oral cavity. Includes lips, oral cavity, and accessory structures such as teeth, palate, tongue, and salivary glands. Details specific anatomical features in different animals.