Anatomy and Histology

Question 1

What are the layers of pleura surrounding the lungs?

Answer 1

1. Visceral pleura (lines where lobes are divided also and forms pulmonary ligament)
   - Potential space: serous fluid
2. Parietal pleura

Question 2

Describe the anatomy of the trachea

Answer 2

• Begins at C6
• Moves down and into the superior mediastinum
• Splits into left and right main bronchi at the T4-5 junction (where inferior mediastinum begins)
• Held open by a series of U-shaped hyaline cartilage rings

Question 3

Describe the anatomy of the bronchial tree:

Answer 3

• Left and Right main bronchi branch at T4-5 junction
• R bronchus is shorter, more vertical and wider and branches earlier
• L and R main bronchi enter lungs at the hilum where they begin to segmentally divide into lobar bronchi -> segmental bronchi (each supplying a functionally distinct bronchopulmonary segment)
• Bronchioles begin at 10-15th branching
• Terminal bronchioles are the final level of conducting system (giving rise to respiratory bronchioles)

Question 4

Where would an inhaled foreign object become lodged if a person was lying on their back?

Answer 4

• Inhaled object would go down R bronchus and apical segment of the R lower lobe
• Drained by placing patient on stomach with pillow under stomach

Question 5

Compare the anatomy of the right and left lungs:

Answer 5

Right Lung:

• Usually larger
• 3 lobes
• 2 fissures (oblique and horizontal)
• Right hilum: 2 bronchi, 2 arteries and 2 veins (most anteiror and inferior) + hilar lymph nodes
• Impressions: right atrium, azygous vein and SVC

Left lung:

• Usually smaller
• 2 lobes + 1 lingula
• 1 fissure (oblique)
• Left hilum: 1 bronchus, 1 artery and 2 veins (most anterior and inferior) + hilar lymph nodes
• Impressions: LV, arch of aorta, descending thoracic aorta

Question 6

Describe the features of respiratory epithelium

Answer 6

1. Pseudostratified ciliated cells: move mucous
2. Goblet cells: secrete mucous
3. Basal stem cells: give rise to new epithelial cells
4. Brush cells with microvilli
5. Serous cells
6. Small granule cells
7. Sensory cells

Question 7

Describe the structure and histology of alveoli:

Answer 7

• Thin walled pouches that arise from the respiratory bronchioles and alveolar ducts
• Made up of type I pneumocytes (simple squamous epithelium that are exchange barrier) and type II pneumocytes (cudoidal cells that secrete surfactant and give rise to new pneumocytes)
• Separated by inter-alveolar septum that contain reticular and elastin fibres and pulmonary capillaries

Question 8

Describe the blood-gas barrier

Answer 8

1. Surfactant
2. Type 1 pneumocyte
3. Basal lamina
4. Connective tissue
5. Basal lamina
6. Endothelial cell
7. Plasma
8. Erythrocyte membrane