Anatomy and Physiology of Nose

Prepared by : Nurul Syazwani Binti Ramli

Anatomy of Nose

Nose

External

Bony Part Cartilaginous Part

Internal (nasal cavities)

Skin-lined portion

(Vestibule)

Mucosa-lined portion (Nasal cavity proper)

External Nose

• Pyramidal in shape (root up & base downward)• Consists of osteocartilaginous framework

covered by muscles and skin.

External NoseNasal Skin-over nasal bone and upper lateral cartilages is thin and freely

mobile-cover alar cartilges is thick and adherent and contain many

sebaceous gland

Nasal Musculature-F(x) : movement of nasal tip, ala and the overlying skin-eg: procerus, nasalis (transverse and alar parts), levator labii

superioris laeque nasi, ant. and post. dilator nares and depressor septi.

Osteocartilaginous frameworkBony Part

-Upper one-third-2 nasal bone

Cartilaginous Part

-lower two-thirds-it consists of :

a) Upper lateral cartilagesb) Lower lateral cartilages (alar cartilages)

c) Lesser Alar (sesamoid) cartilagesd) Septal cartilage

External Nose

Internal Nose

• Divided into right and left nasal cavities• Communicates with:– Exterior: through naris (nostril– Nasopharynx: through post. nasal aperture (choana)

Internal Nose

Vestibule

-lined by skin and contains sebaceous glands, hair follicles and hair (vibrissae)

Nasal Cavity Proper

Has a lateral wall, a medial wall, a roof and a floor

Internal NoseNasal Cavity Proper

Lateral nasal wall

Turbinates (conchae)

-superior-middle-inferior

Meatus

-superior-middle-inferior

Medial wall

Roof

Floor

Internal NoseNasal Cavity Proper

Lateral nasal wall

Medial wall(nasal septum)

1) Columellar septum2) Membranousseptum

3) Septum proper

Roof

Floor

Internal NoseNasal Cavity Proper

Lateral nasal wall

Medial wall

Roof

Anterior Sloping Part :- nasal bones

Posterior Sloping Part :- body of sphenoid bone

Middle Horizontal Part :- cribriform plate of ethmoid

Floor

Internal NoseNasal Cavity Proper

Lateral nasal wall

Medial wall

Roof

Floor

Anterior three-fourths :- palatine process of the maxilla

Posterior one-fourth :- horizontal part of the palatine bone

Lining Membrane of Internal Nose

Vestibule

• Lined by skin containing hair, hair follicles and sebaceous glands

Olfactory region

• Mucous membrane is paler in colour

Respiratory region

• Lined by pseudostratified ciliated columnar epithelium which contains plenty of goblet cells

Mucose membrane

Paranasal Sinuses

Lymphatic Drainage

Blood Supply of Nose

Nasal septum :– Internal carotid :• Anterior ethmoid • Posterior ethmoid

– External carotid :• Sphenopalatine• Greater palatine • Superior labial

Blood Supply of NoseLateral wall :

– Internal carotid :• Anterior ethmoid • Posterior ethmoid

– External carotid :• Sphenopalatine• Greater palatine • Anterior superior dental (infraorbital )• Facial artery

Little’s Area (Plexus Kiesselbach)

– Anterior inferior nasal septum– Anastomoses from :• Anterior ethmoid • Superior labial • Sphenopalatine • Greater palatine

Plexus Kiesselbach

Nerve Supply of Nose• Olfactory nerve :

– Carry sense of smell and supply olfactory region of nose

– Arranged into 10-12 nerves which pass through the cribriform plate and end in the olfactory bulb

• Nerves of common sensation :– Anterior ethmoidal nerve– Sphenopalatine ganglion– Infraorbital nerve – Greater palatine nerve

• Autonomic :– Parasympathetic greater superficial

petrosal vidian sphenopalatine ganglion

– Sympathetic upper 2 thoracic superior cervical gangglion deep petrosal nerve join parasympathetic to form vidian

Physiology of Nose

Functions of the nose:1) Respiration 2) Air conditioning of the inspired air3) Protection of Lower Airway 4) Vocal resonance 5) Nasal reflex functions6) Olfaction

RESPIRATION

• Nose = natural pathway for breathingINSPIRATION: air thru middle part of nose btwn turbinates and nasal septum. Very little air passes thru inferior meatus or olfactory region.

EXPIRATION : same but entire air current is not expelled directly thru nares friction at limen nasi converts it into eddies under cover of inferior and middle turbinates and this ventilates the sinuses thru the ostia

AIR CONDITIONING OF INSPIRED AIR• ‘air-conditioner’ for lungs:

a) Filtration and Purification : nasal vibrissae filters larger particles (3µm) Finer particles adhere to the mucus over surface of mucous

membrane (0.5-3.0µm) Smaller than 0.5µm can pass thru nose into lower airways without

difficultyb) Temperature control : mucous membrane (region of middle and inferior

turbinatesand adjacent parts of the septum) is highly vascular with cavernous venous spaces or sinusoids which control the blood flow)this increase and decrease the size of turbinates efficient ‘radiator’ mechanism to warm up the cold air (near body T0 = 370C)

c) Humidification : adjust relative humidity of inspired air to 75% or more that is essential for integrity and function of ciliary epithelium.

PROTECTION OF LOWER AIRWAYa) Mucociliary mechanism:

Rich in goblet cells, secretory glands both mucous and serous) Form a cont. sheet called mucous blanket which consist of superficial

mucus layer and deeper serous layer that floating on top of cilia which constantly beating to carry it towards nasopharynx = ‘conveyer belt’

b) Enzymes and Immunoglobulins: (in nasal secretion) Muramidase (lysozyme) :- kills bacteria and viruses. IgA and IgE and Interferon :- provide immunity against URTI

c) Sneezing : protective reflex. Foreign particles which irritate nasal mucosa are expelled by sneezing.

VOCAL RESONANCE

• Resonating chamber for certain consonant in speech.

• In phonating nasal consonants ( M/ N/ NG ), sound passes

thru nasopharyngeal isthmus and is emitted thru the nose.

• When blocked, speech becomes denasal.Eg:- M/ N/ NG are uttered as B/ D/ G respectively

NASAL REFLEXES

• Nasal Mucosa reflex receptors closely related to gastrointestinal

and pulmonary functions.

• Examples:

-  irritation of nasal mucosa cause sneezing

-  smell of palatable food reflex secretion of saliva and gastric

juice.

OLFACTION

• Sense of smell:– Animal :- give warning of environmental danger– Man :- for pleasure and enjoing the taste of food

• Olfactory region : – upper one-third of lateral Wall– corresponding part of nasal septum– roof of nasal cavity

• Disorder of smell:– Anosmia– Hyposmia– Parosmia

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