Respiratory Physiology

Question 1

Functions of the upper respiratory tract

Answer 1

Nasal hairs filter inhaled particles
Conchae warm and humidify the inspired air
Olfactory receptors located in the posterior nasal cavity mean that harmful gases can be sensed before being inhaled

Question 2

Pharyngeal constrictors

Answer 2

Inferior, middle and superior constrictor muscles contract to propel food

Question 3

How does the upper airway remain patent during breathing?

Answer 3

Genioglossus dilates the pharynx - relaxes during sleep
Palatal muscles control stiffness and position of the palate
Geniohyoid stiffens the hyoid bone

Question 4

Obstructive sleep apnoea

Answer 4

Relaxation of the pharynx, most symptomatically during stage 3 NREM sleep - the most physically restorative sleep.
Causes daytime irritation, sleepiness, poor concentration.
Associated with hypertension, AF, MI, stroke, impaired glucose tolerance.

Question 5

STOP-BANG - four questions, four objective measures

Answer 5

Snore loudly?
Tired during the day
Observation of stopping breathing during sleep
Pressure - being treated for hypertension

BMI >35
Age >50y
Neck circumference >40cm
Gender - male scores a point

Score greater than 3 = high risk of OSA