The document provides an extensive overview of the oral cavity, including its structure, components, and functions. It details the anatomy of the vestibule, oral cavity proper, palate, teeth, and tongue, outlining their boundaries, tissues, blood supply, and innervation. Additionally, it describes the types of teeth, their development stages, and the sensory structures present within the oral cavity, like taste buds and mucous membranes.

1. ORAL CAVITY ( mouth cavity)
MR KUKIRIZA JOHN

2. • The oral cavity extends from the lips to the
oralpharyngeal isthmus ( junction of the
mouth with the pharynx).

3. • Consists two parts;
• i) vestibule
• ii) oral cavity proper ( mouth proper)

5. Vestibule
• Slit-like space that communicates with the
exterior through the oral fissure.
• It is bounded externally by the cheeks and
lips and internally by the gingivae (gums)
and teeth.
• A mucous membrane line the inner
surfaces of the lips and cheeks and is
reflected onto the gums and teeth
superiorly and inferiorly.

6. Vestibule
• Cheeks form the lateral walls and are
made up of buccinator muscle.

7. Oral cavity proper
• Has a roof formed by the hard palate infront and
soft palate behind.
• The floor is largely formed by the anterior 2/3 of
the tongue and reflection of the mucous
membrane from the sides of the tongue to the
gum on the mandinble.
• A fold of mucous membrane called the
frenulumis found in the mid line which connects
the under surface of the tongue to the floor.

8. Oral cavity proper
• A small papilla on each side of the
frenulum with the opening of the orifice of
the submandibular gland.
• The sublingual fold is a round ridge of
mucous membrane below the tongue
produced by the sublingual gland.

9. Boundaries of oral cavity

12. 1-FRENULUM, 2-DEEP LINGUAL VEIN RIDGE, 3-SUBLINGUAL
FOLD, 4-SUBLINGUAL CURUNCLE(PAPILLA), 5-OPEONING OF
SUBMANDIBULAR DUCT.

14. MUCOUS MEMBRANE
• The oral cavity is lined by a protective
mucous membrane ( oral mucosa).
• It contains many sensory receptors
including taste receptors of the tongue.
• The epithelium of the mucosa is stratified
squamous which is keratinized at the
palate because of the friction subjected at
this point.

15. Cont..
• The epithelium of the mucosa is supported
by dense collagenous tissue known as
the lamina propria.

17. THE PALATE.
• Forms the arched roof of the mouth.
• Separates the oral cavity from the nasal
cavity.
• It consists of two regions;
• i) the anterior 2/3 are bony ( hard palate).
• ii) the mobile posterior 1/3 ( fibro muscular
part) is known as the soft palate.

20. Hard palate
• Formed by palatine process of the maxilla
bone.
• Anteriorly and laterally it is bounded by the
alveolar processes and gingivae.
• It is continuous with the soft palate
posteriorly.
• It is covered by mucous membrane that is
intimately connected to the periosteum.

21. Cont…
• Mucus secreting palatine glands are found
deep to the mucosa of the soft palate.

23. Soft palate
• This is the posterior part of the palate with
no bony framework.
• It is fibro-muscular, movable, and attached
to the posterior edge of the hard palate.
• The uvula is a conical soft tissue which
hangs at the posterior aspect of the soft
palate.
• The soft palate and uvula close off the
nasal pharynx during swallowing.

24. Soft palate
• Laterally the soft palate is joined to the
wall of the pharynx and the tongue by the
palatopharyngeus and palatoglossus
arches respectively ( the muscles forming
these arches taking up the same names).
• Between the above two arches is the
palatine tonsil (lymphoid organ).

27. Nerve and blood supply of the
palate
• Sensory; greater and lesser palatine
nerves branches of pterygopalatine
ganglion.
• Blood supply; greater and lesser palatine
arteries branches of the maxillary artery.

31. TEETH
• Teeth are small, calcified, whitish
structures found in the jaws of many
vertebrates that are used to break down
food.

32. Parts of a tooth
• each tooth consists of two parts;
• i) a crown.
• ii) a neck .
• iii) a root.

33. Crown
• This is the portion which projects into the
oral cavity.
• It is protected by a highly mineralized layer
known as the enamel which cover it
entirely.
• The bulk of the tooth is made up of
Dentine which is covered by the enamel in
the crown part and the cementum in the
root part.

34. Dentine
• Dentine is a calcified tissue of the body.
• Seventy percent of dentin consists of the mineral
hydroxylapatite ( form of calcium), twenty percent is
organic material and ten percent is water.
• Dentin consists of microscopic channels, called dentinal
tubules, which radiate outward through the dentin from
the pulp to the exterior cementum or enamel border. The
tubules contain fluid and cellular structures. As a result,
dentin has a degree of permeability which can increase
the sensation of pain and the rate of tooth decay. In this
way it supports the enamel through transport of
nutrients.

35. Cont…
• The formation of dentin, known as
dentinogenesis, begins prior to the formation of
enamel and is initiated by the odontoblasts of
the pulp which also maintain it.
• The cell bodies of the odontoblasts are aligned
along the inner aspect of dentine against a layer
of predentine where they also form the
peripheral boundary of the dental pulp.

36. The root
• This is embedded in a bony ridge in the
jaw called the alveolar ridge of both the
mandible and maxilla.
• The tooth socket is known as the alveolus.
• The root is invested by a thin layer of
cementum which is connected to the bone
of the socket by a periodontal ligament.

40. Cont…
• There are two sets of teeth which appear
at different periods of time.

41. Deciduous teeth
• These are 20 in number.
• 4 incisors, 2 canines, and 4 molars in each
jaw.
• They begin to erupt at six months after
birth and by the end of the second year all
of them will have erupted.
• The teeth of the lower jaw usually appear
before those of the upper jaw.

43. Permanent teeth
• These are 32 in number.
• 4 incisors, 2 canines, 4premolars, and 6
molars in each jaw.
• They begin to erupt at the sixth year.
• The last tooth to erupt is the third molar
between the 17th
to 30th
year ( wisdom
teeth).

45. Nerve and blood supply to the
teeth:
Branches of maxillary artery ( for upper
teeth):
•Posterior superior alveolar artery
•Middle superior alveolar artery
•Anterior superior alveolar artery

47. Lower teeth:
• Inferior alveolar artery (branch of maxillary
artery)

52. The Tongue
• This is striated muscle covered by mucous
membrane.
• Its anterior 2/3 is found in the mouth and
posterior 1/3 in the pharynyx.

54. Mucous membrane of the tongue
• It is covered by stratified squamous
epithelium non-keratinising.
• It is divided into anterior 2/3 and posterior
1/3 by a v-shaped sulcus terminalis the
apex of which is marked by a small pit
known as foramen cecum.
• It consists of three types of papillae
( structures containing taste buds).

57. Papillae
• i) Filiform papillae; very numerous and
cover the upper surface of the anterior 2/3
of the tongue. They are thin, long
papillae ,"V"-shaped cones that don't
contain taste buds but are the most
numerous. These papillae are mechanical
and not involved in gustation ( taste). They
are characterized by increased
keratinization.

58. Fungiform papillae
• Less numerous than filiform papillae.
• They are red because of the vascular
connective tissue below them.
• They are slightly mushroom-shaped if
looked at in longitudinal section.
• They are present mostly at the apex (tip)
of the tongue, as well as at the sides.
Innervated by facial nerve.

59. Vallate papillae
• 10 to 12 in number.
• Situated in a row immediately infront of the
sulcus terminalis.
• Are innervated by the glossopharyngeal
nerve.

62. Structure of taste bud

63. Muscles of the tongue
• They are divided into two;
• i) intrinsic.
• ii) extrinsic

64. Intrinsic muscles
• Confined to the tongue and not attached to
bone.
• They consist of ; longitudinal, transverse
and vertical fibers.
• They alter the shape of the tongue.

66. Extrinsic muscles
• They are attached to bone and the soft
palate.
• They are ;genioglossus, hyoglossus,
styloglossus, and palatoglossus.
• All except palatoglossus ( pharyngeal
plexux) are supplied by the hypoglossal
nerve. Both intrinsic and extrinsic.

69. Blood supply
• Blood supply is mainly by the Lingual
artery branch of external carotid.
• Veins drain into the internal jugular vein.

71. Nerve supply
• Hypoglossal nerve for motor supply and
pharyngealplexus for palatoglossus.
• Sensory supply for anterior 2/3 by lingual
nerve for general sensation and chorda
tympani branch of the facial nerve for taste
sensation except the vallate papillae.
• General senstion and taste appreciation
from posterior 1/3 including vallate papillae
is by glossopharyngeal nerve.

73. Lymphatic drainage of the tongue
• Tip of the tongue drains into the submental
lymph nodes.
• The remainder of anterior 2/3 of the
tongue drain into the submandibular and
deep cervical nodes .
• Lymph from the posterior 1/3 drains into
the deep cervical nodes.