Session 1

Question 1

What divisions of the airways make up the conduction and respiratory zones?

Answer 1

1-16 = conducting zone.
17-23 = respiratory zone

Question 2

What is responsible for the involuntary breathing pattern?

Answer 2

Neurones in the respiratory centre in the medulla

Question 3

Define Boyle’s law

Answer 3

Pressure is inversely proportional to volume for a fixed quantity of gas at room temperature.

Question 4

Define Dalton’s law

Answer 4

In a mixture of gases, the molecules of each type behave independently so each gas exerts a partial pressure proportional to its volume in the mixture.

Question 5

What happens at equilibrium when a gas mixture is in contact with water?

Answer 5

The partial pressure of the gas in the liquid is equal to the partial pressure of that gas in the gas phase to which the liquid is being exposed to.

Question 6

What does the solubility coefficient of a gas determine?

Answer 6

The amount of gas that will dissolve in a litre of plasma at 37 degrees at a given partial pressure.

Question 7

Define Henry’s law

Answer 7

The amount of gas dissolved is proportional to the pressure of the gas in contact with the liquid.

Question 8

Define saturated vapour pressure

Answer 8

The pressure a gas mixture exerts when it is saturated with water vapour after being in contact with water and is in equilibrium. It only depends on temperature.

Question 9

Why does the pressure of humidified air in the airways always remain at 101KPa?

Answer 9

Because the gas is continuous with outside air. Partial pressure of the other gasses decreases when water vapour is added (total pressure constant) - O2 and N2 slightly diluted.

Question 10

Where is the upper respiratory tract and what is it composed of?

Answer 10

It lies above the cricoid cartilage and is comprises the nose, paranasal sinuses, pharynx and larynx.

Question 11

What are the functions of the upper respiratory tract?

Answer 11

Conducts air to lower airways
Conditions air by warming, humidification and trapping particles
The larynx protects the airway during swallowing and allows speech
The oropharynx and laryngopharynx are involved in swallowing
The olfactory epithelium in the nose give a sense of smell

Question 12

Describe the location of the nasopharynx, oropharynx and laryngopharynx

Answer 12

Nasopharynx - above soft palate
Oropharynx - between soft palate and epiglottis
Laryngopharynx - between epiglottis and cricoid cartilage

Question 13

What divides the nasal cavity?

Answer 13

Medial nasal septum

Question 14

What does the lateral wall of each nasal cavity contain?

Answer 14

3 bony projections called conchae and spaces below each one called meatus. They slow and warm air.

Question 15

What are the 4 paranasal sinuses?

Answer 15

Frontal, ethmoidal, maxillary and spheroidal. They contribute to the warming and humidification of air.

Question 16

How is the URT connected to the ear and eye?

Answer 16

Ear - Eustachian tube between middle ear and nasopharynx

Eye - nasolacrimal duct between eye and nasal cavity

Question 17

What are common causes of upper airway obstruction?

Answer 17

Pharynx - tongue

Larynx - tumours, oedema, bilateral vocal cord paralysis

Question 18

What are the lines of pleural reflection?

Answer 18

The lines between the costal, diaphragmatic and mediastinal surface of the parietal pleura

Question 19

Describe the location of the apex of the lung

Answer 19

It extends ~3cm above the clavicle into the base of the neck

Question 20

Describe the surface markings of the pleural cavity

Answer 20

2nd rib - Two pleural cavities virtually touch
4th rib - left cavity deviates laterally
6th rib - both turn laterally
8th rib - both cross mid clavicular line
10th rib - both cross mid axillary line

Question 21

How does the surface marking from the lungs differ from that of the pleural cavity?

Answer 21

It’s the same except:
The inferior border is two ribs higher
Cardiac notch of left lung curves further laterally

Question 22

What is the name of the inferior part of the pleural cavity not occupied by lung?

Answer 22

Costodiaphragmatic recess

Question 23

Describe the lobes and fissures of the lungs

Answer 23

Left: two lobes (upper and lower) separated by oblique fissure
Right: three lobes (upper, middle and lower) separated by horizontal (higher) and oblique fissures.

Question 24

Describe the surface markings of the fissures of the lungs

Answer 24

Horizontal: from mid axillary line along 4th rib anteriorly
Oblique: T2 Posteriorly to 6th costal cartilage

Question 25

Where do the two domes of the diaphragm come up to?

Answer 25

Right: 5th rib
Left: 5th intercostal space

Question 26

Describe the route of air entering through the nose

Answer 26

Conducting portion:
Nasal cavity -> pharynx -> larynx -> trachea -> primary bronchi -> secondary bronchi -> bronchioles -> terminal bronchioles
Respiratory portion:
-> respiratory bronchioles -> alveolar ducts -> alveoli

Question 27

What is the extrapulmonary section of the respiratory tract?

Answer 27

Nasal cavity to primary bronchi

Question 28

Describe the different types of epithelium present in the respiratory tract

Answer 28

Nasal cavity -> secondary bronchi: pseudostratified with cilia and goblet cells
Bronchioles -> terminal bronchioles: simple columnar with cilia (no goblet)
Respiratory bronchioles -> alveolar ducts: simple cuboidal
Alveoli: simple squamous and type 2 cells

Question 29

How does air alternate between nasal cavities and what is the purpose of this?

Answer 29

Venous plexuses swell every 20-30 mins. Prevents overdrying.

Question 30

Where are the olfactory regions and what cells are present there?

Answer 30

Posterior region of each nasal fossa. Thick pseudostratified epithelium with olfactory cells (bipolar neurones). Serous glands flush odours from epithelial surface.

Question 31

What do secretions of the trachea and bronchi contain?

Answer 31

Mucins, water, lysozymes and antiproteases (inactivates bacterial enzymes)

Question 32

What is the difference between secondary/tertiary bronchi and the primary bronchi?

Answer 32

Cartilages are arranged as irregular crescents or islands, rather than rings.

Question 33

What is the role of surfactant in the bronchioles and what cells produce it?

Answer 33

Keeps airways open during expiration. Clara cells.