2- Nose (Antomy and physiology)

Question 1

nose functions

Answer 1

Functions
- Smell and taste
- Breathing- route for inspired air
o Filters inspired air trapping particle sin nasal hair and mucous
o Moistens (humidifies) and warms
- Resonating chamber for speech

Question 2

Anatomy of the nasal cavity

Answer 2

• External nose (vestibule) from the external nose to the nasopharynx
• Anterior nares= nostrils (apertures)
• Posterior nasal apertures (choanae)

Question 3

External nose

Answer 3

• Made up of cartilage (near the nostrils) and bone
• Important bone = nasal bone (paired bone)
• Clinical correlates
  o Prominence of nasal bone makes them susceptible to fracture in facial injury

Question 4

nose vestibule

Answer 4

The area just inside the nostril (nose opening) that leads into the nasal cavity.
- Lined with skin containing sebaceous/sweat glands and hair-> filters and warms inspired air

Question 5

Nasal cavity

Answer 5

Has bony boundaries and is divided into left and right
x2 lateral walls

Question 6

lateral walls of the nose

Answer 6

Irregular due to presence of bony projections (conchae/ turbinate’s)
- Superior (part of ethmoid)
- Middle (part of ethmoid)
- Inferior (other bone

Turbinates create: meatuses
- superior
- middle
- inferior

Question 7

Opening sunder the meatuses allow for drainage of the

Answer 7

• Paranasal air sinus in nasal cavity
• Nasolacrimal duct in nasal cavity

Question 8

Why does the nose have this irregular anatomy?

Answer 8

• slows airflow by causing turbulence of airflow
• increases surface area over which air passes
• doesn’t always require immediate intervention

Question 9

roof of nasal cavity

Answer 9

Question 10

anterior roof (sphenoid) can be used to

Answer 10

Can be used to access parts of the brain found on the cranial floor
- Transsphenoidal surgical approach- e.g. gaining access to the pituitary gland via the sphenoid bone

Question 11

Medial wall of the nasal cavity

Answer 11

• The septum

Consists of a bony and cartilaginous part
- Anterior= septal cartilage
- Posterior= perpendicular plate of the ethmoid bone and the vomer bone

Question 12

Nerve innervation to the nose and nasal cavity

Answer 12

Trigeminal nerve (V)
- V1- Ophthalmic
- V2- Maxillary
o Majority of nasal cavity (particularly lateral wall) supplies by V2
- V3- Mandibular

Question 13

lining of the nasal cavity

Answer 13

• Vestibule-lined by skin
• Respiratory region and olfactory region - mucous membranes- very vascular

Question 14

Olfactory mucous membrane

Answer 14

• Contains dendrites of olfactory nerves -> smell
• Covers over roof of the nasal cavity (including superior concha/superior part of the septum)

Question 15

Respiratory mucous membrane

Answer 15

• Pseudostratified columnar epithelium
• Rich in goblet cells
• Filters (mucous and cilia)
• Humidifies and warms (rich blood supply)

Question 16

paranasal sinuses

Answer 16

• Air filled spaces that are extension of the nasal cavity
• Rudimentary or absent at birth
• Lined with respiratory mucosa
  o Ciliated and secretes mucous
• Named according to the bone in which they are found
• Various functions – humidify and warm inspired air
  o Reduce weight of the skull
• Drain into the nasal cavity via small channels (ostia in middle conchia) into a meatus
  o Most in the middle meatus
• Infection of nasal cavity involving sinuses (sinusitis)
  o Maxillary sinus most commonly infected

Question 17

label

Answer 17

1- frontal (2,3 or 4)
2- ethmoidal
3- sphenoidal
4- maxillary

Question 18

most commonly infected sinus

Answer 18

maxillary sinus- due to gravity and draining mucus

Question 19

sensory innervation of paranasal sinuses

Answer 19

Va - frontal, ethmoidal, sphenoidal
Vb- maxillary