Lungs

1. Describe the external features of the lung

• Lungs are conical in shape with a base attached to the hilum.
• The hilum contains the structures for blood supply, nerve supply, and lymphatic drainage.
• The apex of the lung is directed upwards and outwards.
• The costal surface is the front surface of the lung facing the chest wall.
• The mediastinal surface is the back surface of the lung facing the mediastinum.
• The lung has two surfaces: the costal and mediastinal surfaces.

2. Compare the features of right and left lungs

• The right lung is larger and has three lobes (upper, middle, and lower).
• The left lung is smaller and has two lobes (upper and lower).
• The right lung is more conical in shape.
• The left lung has a larger upper lobe and a smaller lower lobe.
• The right lung has a longer middle lobe.

3. State the blood supply and nerve supply

• Blood supply:
  • Pulmonary arteries (right and left) carry deoxygenated blood from the heart to the lungs.
  • Pulmonary veins (right and left) carry oxygenated blood from the lungs to the heart.
• Nerve supply:
  • Vagus nerve (cranial nerve X) provides parasympathetic fibers to the lungs.
  • Sympathetic fibers to the lungs are provided by the thoracic splanchnic nerves.

4. Explain the broncho-pulmonary segments and their applied aspect

• Each lung is divided into lobes (upper, middle, and lower for the right lung, and upper and lower for the left lung).
• Each lobe is further divided into bronchopulmonary segments.
• Bronchopulmonary segments are further divided into lobules (smaller units of lung tissue).
• Each bronchopulmonary segment is supplied by a bronchus, artery, and nerve.
• Understanding the bronchopulmonary segments is important for diagnosing and treating lung diseases.

Applied aspects:

• Bronchopulmonary segments are useful for identifying the source of lung disease.
• Each segment can be independently ventilated and perfused, which is useful for lung surgery.
• Understanding the bronchopulmonary segments helps in identifying the level of airway obstruction in lung diseases.