Oral and Nasal Cavity Flashcards Preview

Sc 23 - Head and neck Neuroanatomy > Oral and Nasal Cavity > Flashcards

Flashcards in Oral and Nasal Cavity Deck (22):
1

Two parts of the Oral Cavity

  1. Vestibule
  2. Oral Cavity Proper

2

Vestibule

Space between the teeth and the mucosal inner lining of the cheeks and lips

 

3

Oral cavity proper

Space contained within the upper and lower dental arches

filled by the tongue

4

Oral Cavity

  • Roof
  • Anterior boundary
  • Floor and Posterior Walls

Roof:

  • maxilla bones
  • palatine bones

Anterior boundary: (teeth + front bit of mandible)

  • Maxilla
  • Mandible with their dental arches

Other boundaries (floor & post walls):

- Made up of soft tissues

- Rami of mandible (post boundary)

5

Floor of the mouth

Made up of a muscular sling and mucous membrane

Muscles:

  • Mylohyoid
  • Geniohyoid
  • Anterior belly of digastric

 

6

Lips - Orbicularis Oris

  • Mobile, muscular folds

  • Covered externally by skin and internally by mucous membrane
  • Transitional zone between the two:
    • Vermillion Border:
      • Doesn't contain any glands
      • therefore lips need to be licked to be moistened

N.B. Cheeks have a similar construction, Buccinator muscle in between the two layers

 

 

7

Muscles of facial expression

  • Functions in mouth

Buccinator:

- pushes cheek towards teeth during mastication

- ensures food doesn't fall into vestibule

Lips:

- form a seal preventing food falling out of the mouth during mastication

- form a seal around any vessel pressed against it ensureing liquid enters the mouth and doesn't drip between the mouth and cup

 

Closure of hte mouth and sealing of lips - vital to swallowing 

8

Oral cavity

Contents:

 

  • Teeth 
  • Tongue
  • Ducts of Salivary glands

 

Posteriorly mouth communicates with the Oropharynx

9

Nerve Supply to the Oral Cavity

  • Oral cavity is supplied by a number of cranial nerves

  • Mucous membrane of roof: branch of maxillary nerve
  • Lateral walls & floor: Luingal branch of the mandibular branch of the Trigeminal
  • Muscles in lateral wall: Facial nerve
  • Muscles in floor:
    • Genohyoid - CN I
    • Mylohyoid & Ant belly of digastric - Mandibular branch (nerve to Mylohyoid) of of the Trigeminal
  • Teeth:
    • Alveolar branches of the Maxillary nerve (upper teeth)
    • Mandibular nerve (lower teeth)
      •  

10

Tongue

  • Ant 2/3rds lie in oral cavity
  • post 1/3rd lie in oropharynx

 

Extrinsic muscles: Change position of the tongue

  • Palatoglossus
  • Styloglossus
  • Hyoglossus
  • Genioglosus

Intrinsic Muscles: Change the shape of the tongue

- Sup & inf longitudinal muscles

- Vertical and transverse muscle

11

Nerve supply to the Tongue

All the extrinsic and intrinsic muscles of the tongue are supplied by the:

Hypoglossal nerve CN XII

 

Apart from Palatoglossus which is supplied by the:

Vagus nerve CN X (via the pharyngeal branch to the pharyngeal plexus

12

Where do the ducts of the major salivary glands enter the oral cavity?

  • Parotid Salivary Gland: 
    • Near the 2nd upper molar tooth
    • Secretion : Serous
  • Submandibular Gland:
    • Enters Floor of the mouth
    • Mixed gland - has both serois and mucous secretions
  • Sublingual Gland:
    • between 16 to 20 short ducts which open into the floor of the mouth
    • Secretes mucus

Minor glands: v. imp in maintaining oral hygiene as continual background level of secretion flushes oral surfaces and helps to control the level of bacteria

13

Major Artery of the Tongue

Lingual Artery

  • originates from the External Carotid Artery adjacent to tip of greater horn of the hyoid bone
  • Forms an upward bend then loops downwards to pass under the Hyoglossus muscle
  • Supplies:
    • Tongue
    • sublingual gland 
    • gingiva 
    • oral mucosa in the floor of the oral cavity

14

Venous Drainage of the Tongue

Follows  2 routes:

Posterior lingual veins & deep lingual veins

Posterior Lingual Veins:

  • Drain the dorsum and sides of tongue
  • join the lingual vein which accompanies the artery
  • Near the greater cornu of the Hyoid bone the lingual vein joing the internal jugular vein

Deep Lingual Vein:

  • Begins near the tip of the tongue and runs backwards on its interior surface
  • Near border of hyoglossus, it joins the Sublingual vein, which runs along the course of the Hypoglossal nerve and joins the Facial Vein

 

15

Lymphatic Drainage of the Tongue

Anterior to the Vallate Papillae:

Drained into central and marginal lymph vessels

Posterior 1/3rd:

Drain into posterior lymph vessels

From here they enter a series of nodes the efferent vessels of which drain to nodes surrounding the SCM

16

Functions of the Nose & Nasal Cavity

  • provides an airway for respiration
  • moistens and warms the inspired air
  • filters air to remove foreign particles
  • houses the Olfactory Receptors
  • Acts as a resonating chamber for speech

 

17

Nose

External part: 

- consists of cartilages covered by skin

Internal part:

- Covered by skin too abd contains hair which filters the air

18

Nasal Cavity

  • Made of pseudostratified ciliated columnar epithelium with goblet cells
  • Air:
    • warmed by capillary plexuses in the lamina propria
    • moistened by the glandular secretions
  • Irregular shaped cavity; lies btwn the bony plate of the floor (which separates it from the oral cavity below) and the cribiform plate (which separates it from the cranial cavity above).
  • Cavity is high, deep but narrow and divided into R&L by the nasal septum
  • Ant part of nose in formed by cartilage in life
  • communicates post with nasal part of pharynx; ant with environment; sup with cranial cavity. orbit and paranasal sinuses

 

19

Nasal conchae

Project from the lateral wall of the nasal cavity

as the inhaled air passes over the conchae, the tubercle greatly increases amount of contact btwn mucosa and inspired air.

Particles >4mm rarely get past the nasal cavities

20

Paranasal Sinuses

Surround the nasal cavity

lined by Resp Epithelium

Empty their secretions into the nasal cavity

21

General sensory fibres to the nasal cavity

Branches of the Maxillary and Ophthalmic division of the Trigeminal nerve supply this.

 

 

22

Where are the receptors for the Olfactory nerve located?

In the superior part of the Nasal Cavity