Tracheobronchial Tree and Lungs

Question 1

What are the 3 main functions of the tracheobronchial tree?

Answer 1

The main functions of the tracheobronchial tree include air conduction, humidification and filtration.

Question 2

What type of epithelium lines the respiratory tract?

Clinical Significance?

Answer 2

Question 3

What is the size of the trachea? Where does it run to and from?

• Where does the trachea bifurcate?
• Which bronchus is more likely to have a foreign object lodged?
• What do the main bronchi divide into?

Answer 3

• In adults, the trachea is approximately 2.5 x 10cm tubular structure extending from the larynx to the carina.
• Trachea bifurcates into the left and right main bronchi at the level of T4.
• Right bronchus is wider and more vertical, therefore more likely to lodge foreign bodies.
• Main bronchi divide into lobar bronchi.
• Lobar bronchi divide into tertiary/ segmental bronchi, which divide further until the terminal bronchi.
• Gaseous exchange takes place in the respiratory portion of the lungs.

Question 4

What are the histological changes along the tracheobronchial tree?

Answer 4

Epithelium gets thinner

Question 5

What is the structure of the trachea?

What are the histological layers of the trachea?

Answer 5

Trachea

• C-shaped hyaline cartilages anteriorly.
• Fibroelastic tissues posteriorly.
• Lined by respiratory epithelium.
• Layers:
  
  1. Adventitia.
  2. Cartilage.
  3. Submucosa.
  4. Mucosa.

Question 6

What is the structure of the bronchi & Bronchioles?

• 5 histological layers?
• What 2 things are not present in the bronchioles?
• What epithelium lines the terminal bronchioles?
• Clinical Significance?

Answer 6

Bronchi and bronchioles

• Bronchi are made up of cartilage and circular plates of smooth muscles.
• 5 layers: -
  
  1. Adventitia
  2. Cartilage
  3. Submucosa
  4. Muscularis
  5. Mucosa
• There are no cartilages or glands in bronchioles.
• Terminal bronchioles are lined by simple cuboidal epithelia.
• Clinical significance:
  
  • Bronchoconstriction e.g. asthma.
  • Blockage due to cystic fibrosis.

Question 7

What is a Tracheostomy?

What is a Thyroidectomy?

Answer 7

Question 8

Where do foreign bodies tend to lodge in the airways and why?

Answer 8

Question 9

Answer 9

Question 10

What are the 3 surfaces of the lungs?

Answer 10

Mediastinal, costal & diaphragmatic surfaces.

Question 11

What are the features of the right lung?

What are the surface markings for the oblique and horizontal fissures?

Answer 11

Right lung

• Superior, middle & inferior lobes.
• Surface markings:
  
  • Oblique fissure: spinous process of T4 to 6th rib anteriorly.
  • Horizontal fissure: horizontal line from 4th intercostal space to 5th rib.

Question 12

What are the impressions on the right lungs?

Fissures?

Hilum contents? (5)

Answer 12

Question 12

What are the impressions on the right lungs?

Fissures?

Hilum contents? (5)

Answer 12

Question 13

Left lung surface markings of oblique fissure?

Answer 13

Surface markings Left Lung

• Oblique fissure: spinous process of T4 to 6th rib anteriorly.

Question 14

Impressions on the left lungs?

Answer 14

Question 15

Structures found at the lung hilum? (5)

Answer 15

Structures found at the hilum:

1. Bronchi.
2. Pulmonary artery.
3. Two pulmonary veins.
4. Lymphatics.
5. Pulmonary plexus.

Question 16

Where does gas exchange take place in the lungs?

• 2 Cell types? Which one secretes surfactant?
• Where is the blood-air barrier found?

Answer 16

Lung alveoli

Gaseous exchange takes place in the alveoli.

Alveolar cells:

• Type I pneumocytes.
• Type II pneumocytes secrete surfactant.

Blood-air barrier is found at the alveolar septum.

Alveolar macrophages remove particulate matter/ organisms.

Question 17

Where is the problem?

Answer 17

• Consolidation in the right middle lobe.
• Lobar pneumonia.

Question 18

Where is the pathology?

Answer 18

• Multiple right-sided rib fractures.
• Pneumothorax.