nose structure and function

Upper respiratory track composed of nose, pharynx, larynx. These Structure allow to breathe and speak.


Nose is first respiratory organ.

Air normally enters the respiratory track through nose.

External nose is supported at the nose bridge by nasal bone.

Nasal septum is bone and cartilage in the nose that separates nasal cavity into two nostrils (External nose).

Nasal cavity fills space between base of skull and roof of mouth.

Posterior bony part of septum formed by the perpendicular plate ethmoid bone and vomer.

Roof of Nose

Roof of nose is formed by - cribriform plate of ethmoid bone and inferior surface of body of the Sphenoid bone, nasal part of frontal bone, nasal bone and nasal cartilage.

Floor of Nose

Floor of nose about 5cm long, 1.5 cm wide, formed by roof of mouth consist of palate -

1. Hard palate in front

2. Soft palate behind

1. Hard palate 

Hard palate composed of - palatine process of axillary bone and horizontal palates of the palatine bones.

2. Soft palate (back part of palate)


Movable muscular fold

Separate oropharynx from nasal cavity 

It prevents food from entering nasal pharynx

Continuous with posterior border of hard and consist of several skeletal muscles covered by mucus membrane.

When elevated for swallowing and sucking, it completely blocks and separates nasal cavity and nasal portion of pharynx from mouth and oral part of pharynx.

Middle Wall of Nose

Formed by septum is osseocartilaginous partition between two halves of nasal cavity.

Bony part of septum is formed by -


Prependicular palate of the ethmoid bone

Cartilaginous part formed by -

Septal cartilage

Inferior nasal cartilages (septal processess)

Blood Flow of Septum

Sphino palatine, anterior or posterior ethmoid arteriey,  Superior labial artery (anteriorly).

Lateral Wall of Nose

Partly bony

Partly cartilaginous

Partly made up of soft tissue

Bony part formed by-

Nasal bone


Lacrimal bone

Ethmoid bone with superior and middle conchae

Prependicular palate of palatine bone

Middle pterygoid palate

Posterior Wall of Nose

Formed by posterior wall of pharynx.

Opening into the Nasal Cavity

Anterior nares/ External nares/ nostrils - External openings to the nasal cavity (hair present in this area  )

Posterior (internal) nare, posteriorly nose communicate with pharynx throught two opening called choanae.

Paranasal sinuses

Nasolacrimal duct

Paranasal Sinuses

Paranasal sinus are group of four paired air- filled cavities( sac) that surrounds nasal cavity.

1. Frontal sinuses - above the eyes

2. Ethmoidal sinuses - between the eyes

3. Sphenoidal sinuses - behind the eyes

4. Maxillary sinuses - located under eyes

Sinuses are lined with mucus membrane.

Give voice a full, rich tone and make skull lighter.

Nasolacrimal Duct (Tear Duct)

The nasolacrimal duct begins in the eye socket between maxillary and lacrimal bones.

Carries tears from the lacrimal sac (connected nose to the conjuctival sac of eye) of eye into nasal cavity.

Lacrimal Apparatus

Lacrimal gland (paired) , endocrine gland

Containing orbital structure for tear production and drainage.

Secrete of tear and secretory duct, convey fluid to surface of human eye.

Drain to nasolaryngeal duct.

Lining of Nose

Vascular ciliated columnar epithelium which contains mucus secreting goblet cells.


Nasal conchae are curved bony projections directed down ward and medially.

1. Superior conchae - projection from ethmoid bone

2. Middle conchae - projection from ethmoid bone

3. Inferior conchae - there are independent bone.

Nasal conchae responsible for regulating the air flow through nasal passage. They increases surface area of these cavity thus, providing rapid warming and humidification of air as it passes to lungs. Large surface area maximize warming, humdification and filtering.

Meatuses (Passage) of Nasal Cavity 

Meatuses are air passage way, communicate freely with nasal cavity proper.

Blood Vessels in meatuses are called venous sinuses.

Function of Nose

1. Respiratory function

2. Passage way of air

3. Olfactory function (sense of smell)

4. Protection, nasal hair in nostrils trap large particle preventing entry into lungs

5. Warming cold air to body temperature

6. Humidification and prevent drying

7. Filtering and cleaning air, trap large particles, filtration of dust

8. Modify speech vibration

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