Oral & Nasal Cavities

• nose and nasal cavity

  
  

  what are the nerves that innervate the nasal cavity?

  ophthalmic (anterosuperior) and maxillary (postero-inferior)
• nose and nasal cavity

  
  

  what are the arteries to the nasal cavity?

  ophthalmic, maxillary and facial
• nose and nasal cavity

  
  

  what are the veins to the nasal cavity?

  a plexus leading to the ophtalmic, sphenopalatine and facial
• nose and nasal cavity

  
  

  what are the paranasal sinuses in the nasal cavity?

  maxillary, ethmoid, sphenoid, and frontal.

  
• nose and nasal cavity

  
  

  what is the function of the paranasal sinuses in the nasal cavity?

  Although empty (hence the term 'sinuses') the wall of the sinuses are composed of mucus excreting epithelium

  
  

  - These are emptied into the nasal cavity and act to help moisten the surface of the nasal cavity and of the incoming air
• nose and nasal cavity

  
  

  what is the conchae in the nasal cavity?

  The lateral wall of the nasal cavity shows three circular tube-like protrusions called conchae

  
  

  - The conchae force incoming air to swirl around, which slows it down sufficiently to be warmed and also propel the dust, bacteria etc towards the mucus layer
• nose and nasal cavity

  
  

  describe the nasal cavity


  an irregular shaped cavity bordered by

  Floor: the palatine bone that separates it with the oral cavity

  Roof: the cribiform plate (ethmoid) separating it from the cranial cavity

  
  

  - The cavity is high, deep but narrow and divided into left and right by the nasal septum

  - It communicates anteriorly with the (external) nose and posteriorly with the nasal part of the pharynx

  - The wall is lined by a mucosal layer that makes a sticky sheet. This covers the surface and traps dust, bacteria etc. Cillia then propel it towards the nasopharynx
• nose and nasal cavity

  
  

  describe the nose

  - The external nose is the portion that protrudes from the face

  - Its frame is of cartilage covered by skin

  - The nose can vary considerably in size. However, all have a thick skin covering the cartilage and extending into the nasal opening - nares -where thick hairs help to filter the incoming air
• nose and nasal cavity

  
  

  roles of the nose and nasal cavity

  - Enable the sense of smell

  - Form the upper portion of the respiratory tract

  - Moistens and warms the inspired air

  - Filters the air to remove foreign particles

  - Acts as a resonating chamber for speech
• oral cavity

  cheeks

  
  

  what nerves innervate the cheeks (Buccae)?

  buccal branches (of the mandibular)
• oral cavity

  cheeks

  
  

  what is the blood supply to the cheeks (Buccae)?

  buccal arteries (branches of the maxillary)
• oral cavity

  cheeks

  
  

  what is the role of the cheeks (Buccae)?

  - continuous with the lips and make up the movable walls of the oral cavity.

  - the cheeks enclose muscle - principally the buccinators - that are encapsulated by fat.

  - The cheeks are also involved in suckling, facial expression, speech, etc
• oral cavity

  lips

  
  

  what nerves innervate the lips?

  labial

  
  

  upper from infra-orbital (CN V2)

  lower from mental (CN V3)
• oral cavity

  lips

  
  

  what is the blood supply to the lips?

  upper and lower labial arteries (from facial)
• oral cavity

  lips

  
  

  describe what covers the lips

  The lips are covered externally by skin and internally by mucous membrane, but the transitional zone between these is called the vermilion border.

  
  

  The vermillion border does not contain glands, which is why we need to lick these regularly to avoid becoming dry.
• oral cavity

  lips

  
  

  describe the lips

  musculofibrous folds, containing the orbicularis oris ('orbiting the oral opening') with accompanying vessels and nerves
• oral cavity

  lips

  
  

  what is the role of the lips?

  Lips have a multiple role, from acting as a sphincter, grasping

  food, suckling, speech, etc

  
  

  - they stop food falling of your mouth. (Also preventing disapproving looks if chewing with mouth open)
• oral cavity

  salivary glands

  
  

  what is the role of the minor salivary glands?


  maintain oral hygiene as the continual background level of secretion flushes the oral surfaces and helps to control the level of bacteria
• oral cavity

  salivary glands

  
  

  where does the Sublingual gland enter the oral cavity and what does it secrete?

  - The sublingual gland has between 16 and 20 short duct which open into the floor of the mouth.

  - It is mucus secreting
• oral cavity

  salivary glands

  
  

  where does the submandibular gland enter the oral cavity and what does it secrete?


  - Enters the floor of the mouth.

  - It is a mixed gland having both serous and mucous secretions
• oral cavity

  salivary glands

  
  

  where does the parotid gland enter the oral cavity and what does it secrete?

  - Enters the mouth near the upper 2nd molar tooth.

  - The secretion is serous
• oral cavity

  salivary glands

  
  

  what are the 3 pairs of major salivary glands?

  Submandibular, Sublingual and Parotid

  
  

  - These large glands respond (i.e. excrete) primarily when food

  is in the mouth
• oral cavity

  salivary glands

  
  

  what is the role of the major salivary glands?

  moisten the food dissolving the chemicals which stimulate the taste bud. The moisture in the saliva helps turn the food into a bolus to aid swallowing. Saliva also contains enzymes which begin the process of digestion.
• oral cavity

  tongue

  
  

  what is the lymphatic drainage of the tongue?

  lymph drains ultimately towards the deep cervical

  nodes, that pass it into the general circulation at the venous

  angles (jugular and subclavian
• oral cavity

  tongue

  
  

  what are the 2 routes for venous drainage of the tongue?

  1. The dorsum and sides of the tongue are drained by the posterior lingual veins, that leads to the lingual vein. The

  lingual vein drains to the internal jugular vein

  
  

  2. The remainder is drained by the deep lingual and sublingual

  veins, that join and lead to the lingual vein
• oral cavity

  tongue

  
  

  what is the blood supply of the tongue?

  The tongue receives blood primarily via the lingual artery, a

  branch of the external carotid artery. The artery runs deep to the hypoglossus muscle.
• oral cavity

  tongue

  
  

  what nerves innervate the tongue?

  - All muscles of the tongue except palatoglossus are innervated by the hypoglossal nerve

  - The palatoglossus is innervated by the pharyngeal plexus

  
  

  
  

  The anterior 2/3:

  - general sensation (touch and temperature) of the

  anterior 2/3 is via the lingual nerve, a branch of CN V3

  - taste is via the chorda tympani (from CN VII)

  
  

  The posterior 1/3 and the vallate pappilae:

  - supplied by the lingual branch of CN IX
• oral cavity

  tongue

  
  

  what do intrinsic and extrinsic muscles of the tongue do?

  Intrinsic muscles change the shape of the tongue while

  the extrinsic change its position
• oral cavity

  tongue

  
  

  describe the tongue

  -collection of muscles that together make a mobile muscular special sense organ, covered by mucous membrane

  - involved primarily with taste but also mastication, deglutition, speech or even oral cleansing

  - Has three main parts: a root, body and apex (tip)

  - The anterior 2/3 of the tongue (the body) rests within the oral cavity while the posterior 1/3 (the root) lies in the oropharynx

  - has intrinsic and extrinsic muscles
• oral cavity

  teeth

  
  

  what nerves innervate the teeth?

  alveolar branches of the maxillary (upper) and the mandibular nerve (lower)
• oral cavity

  teeth

  
  

  describe the permanent dentition

  - 32 permanent teeth

  - The primary role of teeth is to cut (aka incise) food, to break it down mechanically, mostly through molar action and, to a lesser degree, to assist with speech

  - Bisected teeth reveal three distinct regions: crown, neck and root (the latter fixed in the tooth socket)

  - Most of the tooth is covered by dentine covered by enamel in the crown region and cement in the root
• oral cavity

  
  

  what are the contents of the oral cavity?

  - teeth

  - tongue

  - ducts of the salivary glands
• oral cavity

  nerve supply

  
  

  what nerves innervate the lateral walls and floor?

  branches of the mandibular division (lingual branch) of the trigeminal
• oral cavity

  nerve supply

  
  

  what nerves innervate the mucous membrane of the roof?


  branches of the maxillary nerve
• oral cavity

  nerve supply

  
  

  what nerves innervate the muscles of the floor?

  - geniohyoid supplied by fibres from C1

  - the mylohyoid & anterior belly of digastric by the mandibular

  branch of the trigeminal
• oral cavity

  nerve supply

  
  

  what nerves innervate the muscles in the lateral walls?

  facial nerve
• oral cavity

  floor of the mouth:

  
  

  what are the soft tissues of the floor of the mouth?


  The floor of the mouth is formed by mucous membrane and

  muscles:

  - Mylohyoid

  - Geniohyoid

  - Anterior belly of digastric
• oral cavity

  roof of the mouth:

  
  

  describe the palatine


  makes up for the remaining 1/3 of the roof.

  - Also the attachment for the soft palate

  
• oral cavity

  roof of the mouth:

  
  

  describe the maxilla


  separates the oral from the nasal cavity.

  
  

  It makes up for:

  - the anterior boundary of the upper part of the oral cavity and

  - the anterior 2/3 of the roof

  
• oral cavity

  
  

  what are the 3 boundaries of the oral cavity?

  Roof: the maxilla and palatine bones

  Anterior: maxilla and mandible, inc the dental arches

  Floor and posterior wall: soft tissues