Physiology of the airway

Question 1

what is the difference between nasal and mouth breathing

Answer 1

nasal breathing through the sinus’ causes conditioning

mouth breathing - inspiration genioglossus contracts and tensor palati is isolated opening the throat

Question 2

what are the types of activity that control airway breathing

Answer 2

tonic and phasic

Question 3

describe the pharyngeal dilator reflexe

Answer 3

negative pressure during inspiration triggers pressure receptors which send impulses via the 5th nerve (trigeminal) to the brainstem which sends an efferent response to the vagus nerve and to pharyngeal muscle contraction

Question 4

what is the speed of the pharyngeal dilator reflex

Answer 4

50 ms

Question 5

what affects the speed of the pharyngeal dilator reflex

Answer 5

slows down in breathing meaning less efficient

Question 6

what happens when the pharyngeal breathing reflex stops working

Answer 6

you get snoring and sleep apnea which is prevalent in 25% and 10% of the population respectively

Question 7

what is the definition of sleep apnea

Answer 7

stop breathing for more than ten seconds repeatedly

Question 8

what is arousal in sleep apnea

Answer 8

when you wake up slightly as if dosing to restore normal breathing pattern

Question 9

what are the clinical features and associations and treatment for sleep apnea

Answer 9

snoring
daytime somnolence
associated w/ obesity and hypertension
treatment - weight loss and CPAP - continuous positive air pressure - pushing air into the lungs

Question 10

the reflex control of the muscles in breathing is rapid and critical - what substances affect this

Answer 10

sedative drugs

Question 11

what are the three types of cells in the different locations of the airway

Answer 11

nose and pharynx is pseudo stratified
trachea and bronchi are columnar
bronchioles are cuboidal

Question 12

what are the two cell types in the airway lining

Answer 12

ciliated epithelial cells and goblet cells

Question 13

what do goblet cells do and in response to what

Answer 13

release mucous in response to airway irritation tobacco and infection

Question 14

describe the rough three layers in airway lining

Answer 14

top mucous layer - middle periciliary layer - bottom epithelial cells

Question 15

what are the movements of the cilia

Answer 15

recovery stroke and an effective stroke which moves about 4mm/min

Question 16

what are the cilia inhibited by

Answer 16

tobacco smoke, mainly cyanide
inhaled anaesthetics
air pollution
infections

Question 17

what are the two functions of the airway

Answer 17

humidification and airway defence

Question 18

how does humidification of air occur

Answer 18

nose breathing into sinus’
there is heat and moisture exchange which removes excess heat and moisture from expired air and returns it to more inspired air

Question 19

what are the two mechanisms airway defence

Answer 19

muco-ciliary escalator

expectoration - coughing

Question 20

what happens to airways in cystic fibrosis

Answer 20

CFTR protein in epithelial cells
inactivated stoping influx of Na and Cl meaning more nail in airway lining fluid and human defencin cannot bind and inactivate bacteria

Question 21

what are the clinical features of cystic fibrosis

Answer 21

autosomal recessive inheritance - 1 in 2500 births
progressive lung infection and destruction affects all systems with epithelial surfaces such as gastrointestinal and urogenital

Question 22

for very large particles >8 microns, where are they deposited, via what mechanism and examples

Answer 22

nose and pharynx, inertial importation and pollen / sawdust

Question 23

for large particles between 3 - 8 microns where are they deposited, what is the mechanism and what are examples

Answer 23

large airways, inertial impaction, fungal spores

Question 24

for small particles between 0.5 and 3 minors where are they deposited, what is the mechanism and what are examples

Answer 24

bronchioles, sedimentation, particle pollution, stone dust, asbestos

Question 25

for very small molecules less than 0.5 microns where are they deposited, what is the mechanism and what are examples

Answer 25

they are exhaled, via diffusion - examples are smoke from cigarettes

Question 26

for inhaled drug discovery
where is the site of deposition and potential uses for large (greater than 5 microns), medium 1-3 microns and small 0.5-1 microns

Answer 26

large - pharynx and large airways - hay fever
medium - small airways - asthma and COPD
small - alveolus - absorption into the blood

Question 27

in an inhaler what is the range of particle sizes

Answer 27

1-35 microns

small are beneficial to brnochioles and large particles affect the pharynx but can have side effects

Question 28

what are the non-immunological systems for pulmonary defences

Answer 28

1 - physical barrier and removal which is the main process
2 - chemical inactivation - lysosome degradation, protease enzymes such as elastase (require antiprotenase to make sure normal cells aren’t effected)
antimicrobial peptides eg human b defences
3 - alveolar macrophages

Question 29

what are the two types of immunological systems for pulmonary defences

Answer 29

humoral and cell mediated

Question 30

what are the humeral molecules in pulmonary defences

Answer 30

IgA - (nose and large airways)
IgG (small airways)
IgE (allergic disease)

Question 31

what are the cell mediated responses in pulmonary defences

Answer 31

epithelia cells
macrophages
neutrophils - infection
eosinophils - allergy

Question 32

what do you breath in the environment

Answer 32

CO 
nitrogen oxides 
ozone
particulate matter 
indoor - cooking (gas and wood) 
outside (vehicles and power stations)

Question 33

how do CO
nitrogen oxides 
ozone
particulate matter 
effect breathing

Answer 33

decreased O2 carriage
airway irritation and asthma
airway irritation and cough
lung and systemic inflammatory response

Question 34

how many deaths per year in the Uk are due to air pollution

Answer 34

40k