Nasal Cavity

Question 1

What are the functions of the respiratory system?

Answer 1

1) Warm, humidify and filter inhaled air.
2) Olfaction.
3) Help produce sound.
4) Provide 02 and remove CO2.
5) ACID-BASE BALANCE
6) Protective and reflexive non breathing movements.
7) Assist circulation of blood and lymph towards the heart.
8) Help the abdominal muscles during defecation, parturition, and lifting heavy objects.

Question 2

What are the physical requirements of the respiratory system?

Answer 2

1) Large surface area for gas exchange,
2) Thin-walled membrane,
3) Selectively permeable membrane
4) Moist membrane as O2 and CO2 can be dissolved in water to facilitate diffusion.
5) Extensive capillary network
6) Effective ventilation to constantly replenish the air
7) Must function autonomically

Question 3

What composes the upper and lower respiratory tract?

Answer 3

Upper = Nose and nasopharynx.

Lower = Larynx, trachea, bronchial tree, alveolar ducts, pulmonary alveoli and alveolar sacs

Question 4

What composes the conducting and respiratory division of resp system?

Answer 4

Conducting = Nose, nasopharynx, larynx, trachea, bronchial tree.

Respiratory = Alveolar ducts, pulmonary alveoli and alveolar sac.

Question 5

What is the function of the muscles around the nostrils?

Answer 5

Act as sphincters or dilators to control diameter of nares and adjust air flow.

Question 6

What makes up the medial wall of the nasal cavity?

Answer 6

It is the septum which is made out of bone posteriorly (Vomer and ethmoid) and anteriorly is made up of cartilage

Question 7

What is the roof and floor of the nasal cavity composed of?

Answer 7

Roof: Nasal, frontal, ethmoid and sphenoid bones

Floor; Palatine bones and maxilla, hard and soft palates.

Question 8

What is the lateral wall of the nasal cavity made up off?

Answer 8

Conchae (which when covered with mucosal membrane it is called turbinates), these are projections from the lateral walls the air tunnels are called meatuses.

Question 9

What is the function of chonae?

Answer 9

Increase surface area, and form air channels

Question 10

Name the gateways in the nasal cavity and what passes through them

Answer 10

• Foramen caecum (connection between nasal veins and superior sagittal sinus),
• Cribriform plate (olfactory nerve),
• Sphenopalatine foramen (Sphenopalatine artery, Nasopalatine nerve and superior nasal branches of maxillary nerve),
• Small foramina (inferior branches from greater palatine nerve),
• Incisive canal ( nasopalatine nerve and terminal end of greater palatine artery).

Question 11

Describe features of paranasal sinuses

Answer 11

• Bone surrounding nasal cavity is excavated to form maxilla, ethmoid, frontal and sphenoid sinuses. Nasal mucosa extends into sinuses. They lighten the skull and are innervated by branches of trigeminal nerve.

Question 12

Describe paranasal sinuses in infants

Answer 12

They are only formed in early childhood to adolescence so new-borns cannot develop sinusitis

Question 13

Where does the frontal sinus drain?

Answer 13

Via frontonasal duct to ethmoidal infundibulum (middle meatus)

Question 14

Where does the maxillary sinus drain too?

Answer 14

Middle meatus

Question 15

Where do the middle and anterior ethmoid sinuses drain too?

Answer 15

Middle- Bulla ethmoidalis.

Anterior - ethmoidal infundibulum.

Both then drain to middle meatus

Question 16

Where does the posterior ethmoid sinus drain too?

Answer 16

Superior meatus

Question 17

Where does the sphenoid sinus drain too?

Answer 17

Spheno-ethmoidal recess and then to superior meatus

Question 18

Where does the nasocrimal duct drain too?

Answer 18

Inferior meatus. No parasternal sinuses drain to inferior meatus

Question 19

What is important about the opening of the maxillary sinus?

Answer 19

It has a superior opening which means in the cillia are not functioning properly then it can cause accumulation of mucus and eventually lead to maxillary sinusitis.

Question 20

What is the arterial supply of the nasal cavity?

Answer 20

• Terminal branches of maxillary and facial arteries,
• Ethmoidal branches and ophthalmic arteries,
• Anastomosis between internal and external arteries

Question 21

What is the arterial supply of the septum?

Answer 21

• Sphenopalatine artery,
• Anterior and posterior ethmoidal artery,
• Branches of the greater palatine artery,
• Superior labial artery

Question 22

Where is the site of anastomosis for the arteries of the septum and its significance?

Answer 22

‘Little’s or Kiesselbach’s Area’ On the septum, it is a site for epistaxis.

Question 23

What is the arterial supply of the sinuses?

Answer 23

F - Supra-orbital and anterior ethmoidal artery.

E - Anterior and posterior ethmoidal and sphenopalatine arteries

S - Posterior ethmoidal

M - Infraorbital and superior alveolar branches of maxillary artery and the greater palatine artery.

Question 24

Describe the venous drainage of the nasal cavity

Answer 24

Tend to follow arteries. They drain to pterygoid plexus, facial veins or cavernous sinus. Some may join emissary veins which can allow spread of infection into cranial cavity

Question 25

Describe the lymphatic drainage of the nasal cavity

Answer 25

Anteriorly - Submandibular nodes.

Posteriorly - Retropharyngeal nodes to upper cervical nodes

Question 26

Describe the nerve supply of the lateral wall of the nasal cavity

Answer 26

Supplied by ophthalmic (V1) and maxillary (V2) divisions of the trigeminal nerve. V1 gives off the anterior ethmoidal branches and V2 the gives of the greater palatine nerve which supply the lateral wall.

Question 27

Describe the nerve supply of the septum

Answer 27

It is also supplied by ophthalmic (V1) and maxillary (V2) divisions of the trigeminal nerve. However supplied by anterior ethmoidal and septal branches of V1 and nasopalatine branch from V2.

Question 28

Describe the nerve supply of the paranasal sinuses

Answer 28

F - V1 which gives off supra-orbital N.

E - V1 which gives nasocillary n.

S - V1 which gives posterior ethmoidal n.

M - V2 which gives of infra-orbital, middle, posterior and anterior superior alveolar nerves.

Question 29

What is the choanae

Answer 29

The oval-shaped openings between the nasal cavities and the nasopharynx. It is a rigid.

Question 30

What connects the middle ear cavity to the nasopharynx?

Answer 30

The pharyngotympanic (auditory) tube. The opening of which is located on the inferior-lateral wall on the nasal cavity

Question 31

What are the two tonsils in the nasopharynx?

Answer 31

Tubal tonsils which are located around the opening of the pharyngotympanic tube. Pharyngeal tonsil on the roof.

Question 32

What forms the salpingopharyngeal and salpingopalatine folds?

Answer 32

When a mucosal membrane covers the salpingopharyngeal and salpingopalatine muscles which run between the torus tubarius and pharynx/palate.

Question 33

Where is the pharyngeal recess and its clinical significance?

Answer 33

It is behind the auditory tube. It is the most common site for craniopharyngioma. When inserting catheter into auditory tube, it can miss and entre the pharyngeal recess and if the pharynx is pierced then it may damage internal carotid. Also where adenohypophysis develops from.

Question 34

What is the Waldeyer’s Ring and what is it made up of?

Answer 34

A ring of tonsils around the openings of the respiratory and gastro-intestinal tracts Formed by the nasal cavity tonsils - left and right tubal and the pharyngeal. And the oral cavity tonsils - Left and right palatine and lingual.

Question 35

What is the clinical significance of the pharyngeal and tubal tonsils?

Answer 35

Swelling of the tonsil in children can obstruct the airway and lead to mouth breathing.

Enlargement of the tubal tonsil may obstruct the pharyngotympanic tube and cause middle ear infections.