Lecture 11: Upper respiratory tract

Question 1

What is the main type of epithelium that lines most of the respiratory tract?

What is the function of epithelium?

Answer 1

Pseudostratified, ciliated, columnar epithelium containing goblet cells. Respiratory mucosa sits on top of a vascular plexus(network) that allows air to be warmed

• to warm, humid and clean the inhaled air

Question 2

What is the main function of the epiglottis ? (trap door)

Answer 2

• Protects the air way

Question 3

What are the four structures of the URT?

Answer 3

1. Nose/nasal cavities
2. Paranasal sinuses
3. Pharynx = nasopharynx + oropharynx + larynogopharynx
4. Larynx

Question 4

What is the function of the larynx?

Answer 4

Function: conducts and protects the air way from collapse - 9 cartilages

• SOUND PRODUCTION
• below the entrance to the oesophagus, cilia trap inhaled debris and propel is towards the pharynx

Question 5

What is the structure of the larynx?

Answer 5

• composed of 9 cartilages which protect and maintain an open air way
• extends from the hyoid bone to oesophagus
  region air & food pass = stratified sqaumous epithelium —-> protects throat from increased friction by ingested food
  region air only = respiratory mucosa

Question 6

What is the structure of paranasal sinuses?

Answer 6

• A ring of sinuses/cavities which surround the nose

= frontal, sphenoid, ethmoid and maxillary sinuses

Question 7

What is the function of paranasal sinuses?

Answer 7

• Sinuses lighten the skull & help warm moisten air
• Sinuses allow sound resonance
• Sinus mucus drains into the pharynx

Question 8

What is the function of the nose/nasal cavities?

Answer 8

CLEANING THE AIR

• on lateral walls there are 3 mucosa = superior, middle and inferior turbinates
• —> which swirl the air so heavier particles are deflected into the mucosa
• —> turbulence assists the cleaning of incoming air
• —> triggering of sensory nerves activate sneeze complex

Question 9

What mucous membranes line the nasal cavity?

Answer 9

Olfactory mucosa: lines the slit - opening at the roof of the nasal cavity which contain smell receptors
Respiratory mucosa: pseudostratified, ciliated, columnar epitheliym containing goblet cells.
region food and air = stratified sqaumous epithelium
region air only = respiratory mucosa

Question 10

What lines the nose?

Answer 10

The Vestibule region(region just inside the opening of the nose) is lined with skin that contains sebaceous glands, sweat glands and hair follicles
- Hairs(vibrissae) filter coarse particles e.g dust, lint, pollen etc for inhaled air = protection

Question 11

The nasopharynx is part of the pharynx - Where is it located? What is its function?

Answer 11

Located: posterior to the nasal cavity. It extends from the posterior nares to the soft palate
- during swallowing the soft palate & uvula swing back and up preventing food form entering the nasal cavity

Question 12

The oropharynx is part of the pharynx - where is it located? What is its function?

Answer 12

Located: posterior to the oral cavity. It extends from the soft palate to the epiglottis.

• both air and food pass through
• epithelium changes to stratified sqaumous epithel which protects the throat from increased friction from food during ingesting
• contains palatine and lingual tonsils

Question 13

The larygopharynx is part of the pharynx - where is it located? What is its function?

Answer 13

Located: below the epiglottis - extends to the larynx when the respiratory and digestive tracts diverge
- during swallowing food has the ‘right of way’ over air and breathing is paused.