Oral cavity anatomy and histology Tongue, Oral mucosa

1. Anatomy of the
mouth
QPT 20704
DR Mohand

2. Learning objective
At the end of the seseion student should be able
to:
1. Describe about oral cavity
2. Describe about lips
3. Describe about teeth

3. Functions of the Digestive
System
 Ingest food
 Break down food into nutrient molecules
 Absorb molecules into the bloodstream
 Rid the body of indigestible remains

4. Main Divisions of the Digestive System
 Alimentary Canal
Continuous, muscular digestive tube winding throughout the
body
Digests and absorbs food particles
Contains the following organs:
Mouth, Pharynx, Esophagus, Stomach, Small and Large Intestines
 Accessory Digestive Organs
Contains the following organs:
Teeth, Tongue, Gallbladder, Salivary Glands, Liver, and Pancreas

5. Digestive System Divisions

6. Digestive Processes
 Ingestion
 Propulsion
 Mechanical digestion
 Chemical digestion
 Absorption
 Defecation

7. Slide 14.3
Organs of the Alimentary Canal
 Mouth
 Pharynx
 Esophagus
 Stomach
 Small intestine
 Large intestine
 Anus

8. Oral cavity
Initial point of entry of food into GI tract
• Is the first site for beginning the breakdown of food into its
constituent molecules (lipids → fatty acids, carbohydrates →
simple sugars & protieins → amino acids) for absorption into the
body.
• Consists of lips, cheeks, tongue, teeth, salivary glands, palate.
• Lined with a thick stratified squamous epithelium

9. Mouth (Oral Cavity)
• The opening through
which food is taken in
and vocalizations
emerge.
• The cavity lying at the
upper end of the
alimentary canal,
bounded on the outside
by the lips and inside by
the oropharynx .

10. Mouth (Oral Cavity)
• Oral cavity:
– has a roof and floor, and
lateral .
– The roof = hard and soft
palates.
– The floor = a muscular
diaphragm and the tongue.
– The lateral walls =
(cheeks) are muscular
– Anterior = the lips
surrounding the oral
fissure
– Posterior = the oropharynx

11. Mouth (Oral Cavity)
The entire oral cavity is lined with mucous membrane tissue.
The oral cavity consists of the following two areas:
The vestibule (outer smaller portion) is the space between
the teeth and the inner mucosal lining of the lips and cheeks.
The oral cavity proper (inner lager portion) which is enclosed
by the dental arches.

12. Mouth (Oral Cavity)
• The vestibule:
• It is a narrow space
• It is
horseshoe
shaped,
• It is between the
dental arches and
the deep surfaces
of the cheeks and
lips.

13. Mouth (Oral Cavity)
The oral cavity proper:
It is bounded:
• Antrolateral : the teeth ,
gums and alveolar
arches of the jaws.
• The roof: hard and soft
palates
• The floor: posteriorly by
the dorsum of the
tongue and anteriorly
by the sublingual region

14. Sensory Innervations of the Mouth
• Roof: The greater palatine and nasopalatine
nerves from the maxillary division of the
trigeminal nerve (CN V)
• Floor: The lingual nerve (common sensation), a
branch of the mandibular division of the
trigeminal nerve (CN V). The taste fibers travel in
the chorda tympani nerve, a branch of the facial
nerve (CN VII).
• Cheek: The buccal nerve, a branch of the
mandibular division of the trigeminal nerve(CN V)

15. Lips
• Lips are the visible
parts of the body
• Lips are soft pliable
• Anatomical structures
that form the mouth
margin

16. Lips
STRUCTURE
• Core of sphinchter-shape
skeletal muscle (orbicularis
oris).
• The outer skin contains hair,
sweat glands, and sebaceous
(oil) glands.
• The edges of the lips are
covered with reddish skin,
sometimes called the vermilion
border, and abundantly
provided with sensitive nerve
endings.

17. Lips

18. Lips
• “Red margin” transition from
keratinized skin to oral mucosa
– Red because clear color lets
underlying vessels show
through
– No sweat or sebaceous
glands, thus needs to be wet
(or lip balm)

19. Muscles of Lips
• The skeletal muscle is •
orbicularis oris.
• The muscles acting on the
lips:
– Sphincters of the oral orifice
o Buccinator
o orbicularis oris
• Lip depression
– Risorius
– Depressor Anguli Oris
– Depressor Labii Inferioris
– Mentalis
Lip elevation
– Levator labii superioris
– Levator labii superioris
alaeque nasi
– Levator anguli oris
– Zygomaticusminor
– Zygomaticus major

22. Nerve Supply of Lips
– Motor Innervation
• Facial nerve VII
– Buccal
» Elevators of
commissures and
orbicularis oris
– Marginal
mandibular
» Lipdepressors
– Sensory innervation
• Trigeminal nerve V

23. Blood supply and Lymphatic drainage
of Lips
– Bloodsupply
• Derived from the facial
arteries
– Superior and inferior labial
branches
– Travel tangentially deep to
the orbicularis oris muscles
– Lymphatic drainage
• Primarily submental and
• submandibular node

24. Teeth

25. The Dentitions
The term dentition is used to describe the
natural teeth in the jawbones.
• Primary dentition is the first set of 20 primary
teeth. - “baby teeth” or “deciduous teeth”
• Permanent dentition - 32 secondary or
“adult” teeth.
• Mixed dentition occurs when both primary
and permanent teeth are present, usually
between the ages of 6 to 12.

26. Primary dentition
• Primary dentition is the
first set of 20 primary
teeth. Also referred to as
“baby teeth” or
“deciduous teeth”
(4I , 2C , 4M ) X 2 =20

27. Permanent dentition
• Permanent dentition
Permanent teeth are 32
in number “adult”
teeth.
• (8 incisors , 4 canines , 8
premolar s ,12 molars)

28. Eruption of teeth
Deciduous teeth Permanent teeth

29. Deciduous teeth

30. Eruption & Exfoliation
• Eruption is the movement of the tooth
through the surrounding tissues so that more
of the tooth becomes visible in the mouth.
• Exfoliation is the process by which the roots
of the baby tooth are resorbed and dissolved
until so little root remains that the baby tooth
falls out.

31. Occlusion
• Occlusion is the relationship of
the mandibular and maxillary
teeth when closed or during
excursive movements of the
mandible; when the teeth of
the mandibular arch come into
contact with the teeth of the
maxillary arch in any
functional relationship.

32. Dental arches
• Dental arch: the curving
structure formed by the
teeth in their normal
position; the inferior
dental a. is formed by
the mandibular teeth,
the superior dental a.
by the maxillary teeth.
• If the teeth are
removed, the alveolar
bone is resorbed and
the arches disappear.

33. Dental arches
• The maxillary arch (upper
arch), actually part of the
skull, is fixed and not
capable of movement. The
teeth in the upper arch are
set in the maxilla, the maxillary
bone.
• The mandibular arch (lower
arch) is capable of
movement through the
action of the
temporomandibular joint.
The mandible, the
mandibular bone supports the teeth
in the lower arch.

34. The Gingivae (gums)
• The gingivae are
specialized regions of
the oral mucosa that
surround the teeth and
cover adjacent regions
of the alveolar bone.

37. Teeth
• Each tooth is made of a
crown, a neck and a
root
• A hard covering called
enamel and dentin
covers the crown with
an inner pulp area with
nerves and blood
vessels

38. Teeth
Each tooth has 3 parts
• Crown (exposed part of
the tooth above the
gingiva (gum)
• Root (Embedded in the
jaw )
• Neck ( Between the
crown and root )

39. Teeth
• Dentine : underlies the
enamel cap and form
the bulk of the tooth.
• Cementum : The
external surface of the
root is covered by a
calcified connective
tissue.

40. Teeth
• Enamel – acellular,
brittle material
composed of calcium
salts and hydroxyapatite
crystals is the hardest
substance in the body
– Encapsules the crown of
the tooth

41. Teeth
• Periodontal ligament
– Anchors the tooth in the
alveolus of the jaw
– Forms the fibrous joint
called a gomaphosis
• Gingival sulcus –
depression where the
gingiva borders the
tooth

42. Teeth• Pulp cavity – cavity
surrounded by dentin
that contains pulp
• Pulp – connective tissue,
blood vessels, and nerves
• Root canal – portion of
the pulp cavity that
extends into the root
• Apical foramen – proximal
opening to the root canal
• Odontoblasts – secrete
and maintain dentin
throughout life

43. Types of Teeth
• Incisors teeth are single-
rooted teeth with a
relatively sharp thin edge
referred to as the incisal
edge.
• Located in the front of the
mouth, they are designed
to cut food without the
application of heavy forces.
• Central (front teeth) and
lateral (distal to the
centrals) teeth are incisors.

44. Types of Teeth
• Canines teeth, also
known as cuspids, are
located at the corner of
the arch. They are
designed for cutting and
tearing foods, which
require the application
of force.

45. Types of Teeth
• Premolars teeth are a
cross between canines
and molars. An older
term for premolar is
bicuspid. The pointed
cusps hold and grind the
food.
• They have abroader
surface for chewing
food. There are two sets
of premolars in the
permanent dentition
and NO premolars in the
primary dentition.

46. Types of Teeth
• Molars teeth are much
larger than premolars.
The molars have more
cusps than other teeth
that are used to chew
or grind up food.
• There are two sets of
molars in the primary
dentition and three sets
of molars in the
permanent dentition.

47. Types of Teeth

48. Types of Teeth

49. Blood Supply of The Teeth
• All teeth are supplied either directly or
indirectly from the maxillary artery by:
• Inferior alveolar artery All lower teeth
• Anterior and posterior superior alveolar
arteries All upper teeth
• Veins from the upper and lower teeth
generally follow the arteries.

50. Blood Supply of The Gingivae
The gingivae are supplied by multiple vessels:
• Buccal gingiva of the lower teeth is supplied by
branches from the inferior alveolar artery
whereas the lingual side is supplied by branches
from the lingual artery of the tongue;
• Buccal gingiva of the upper teeth is supplied by
branches of the anterior and posterior superior
alveolar arteries;
• Palatal gingiva is supplied by branches from the
nasopalatine and greater palatine arteries.

51. Innervation of The Teeth And Gingivae
• All nerves that innervate the teeth and
gingivae are branches of the trigeminal nerve
[V]

52. Lymphatic Drainageof The Teeth And
Gingivae
• Lymphatic vessels from
the teeth and gingivae
drain mainly into
submandibular,
submental, and deep
cervical nodes

53. Exercise
1. Compare and contrast between permanent
and deciduous teeth
2. Compare and contrast between incisor and
molar teeth

54. Thank You