Thorax Lungs Question And Answers

Lungs Question And Answers

Question 1. Describe the gross features of the right and left lungs. Mention the relations of mediastinal surface of both lungs.
Answer:

Right and Left Lungs

• Paired organs of respiration
• Lie on either side of the mediastinum
• They are covered by pleura

• Lungs receive air through the bronchi, which are the continuations of the trachea
• The right lung is larger than the left (since the heart bulges more to the left)
• At birth its grey in color, later it becomes black due to the deposition of carbon particles through inhalation
• Weight: Right lung – 700 g, left lung 600–650 g
• Shape: Cone-shaped
• It has:
  • Apex: Upper end, 2.5 cm above the medial 1/3rd of the clavicle
  • Base (Broader inferior surface): Sits on the diaphragm
  • Two surfaces:

1. Costal surface
   • Rounded lateral surface
   • It is in relation to ribs and intercostal spaces
2. Mediastinal surface
   • Medial surface
   • Relations:
     • Anteriorly: Mediastinum
     • Posteriorly: Thoracic vertebral column
     • Three borders
       1. Anterior border: Sharp border
          • Lies anteriorly
          • It separates costal and mediastinal surfaces
       2. Posterior border: Smooth rounded border
          • It separates the vertebral and costal surfaces
       3. Inferior border: Sharp border
          • It separates the base from the other two surfaces.

• All the surfaces of the lung are covered by the visceral pleura except at an area in the mediastinal surface, called as the hilum
• The pulmonary artery and principal bronchus enters the lung and pulmonary vein leaves the lung through the hilum.

Read And Learn More: Anatomy Question And Answers 

 

Right and Left Lungs Blood Supply of Lung

• Arterial Supply
  • Right side: One bronchial artery (Branch of 3rd posterior intercostal artery)
  • Left side: Two bronchial arteries (Branch of descending thoracic aorta).
• Venous Drainage
  • Right side
    • Superior and middle lobes: Upper pulmonary vein
    • Inferior lobe: Lower pulmonary vein
  • Left side
    • Superior lobe: Upper pulmonary vein
    • Inferior lobe: Lower pulmonary vein

Right and Left Lungs Nerve Supply

• Receives autonomic nerves from the anterior and posterior pulmonary plexus.
  • Sympathetic nerves: Bronchial dilatation
  • Parasympathetic nerves: Bronchial constriction.

Lymphatic Drainage :Drained by two sets of vessels.

1. Superficial
2. Deep.

Right and Left Lungs Applied Anatomy

• Bronchitis: Inflmmation of the bronchi
• Pneumonia: Inflammation of the lung parenchyma
• Obstruction of the bronchus due to any cause can lead to the collapse of the part supplied by it.

Question 2. Write a note on the development of lungs.
Answer:

Development of Lungs

• Lungs developed from lung buds which develops at the caudal end of the laryngotracheal tube
• It divides into two knob-like bronchial buds, which grows into celomic ducts, the primordia of pleural cavities
• They are surrounded by splanchnic mesenchyme
• Each bronchial bud enlarges to form primary bronchus
• Primary bronchus on the right side forms superior and inferior secondary bronchi, on the left side forms two secondary bronchus for superior and inferior lobes
• Secondary bronchus forms tertiary bronchus. Ten on right and nine on the left side each And surrounding mesenchyme gives rise to a bronchopulmonary segment
• Cartilage, smooth muscles, connective tissue, and capillaries are derived from surrounding splanchnic mesenchyme
• Visceral pleura from splanchnic mesoderm and parietal pleura from somatopleuric mesoderm.

Question 3. What is root of lung?
Answer:

Root of Lung

• It is a short pedicle
• It attaches the medial surface of lungs to the mediastinum
• It is formed by structures passing between the lungs and mediastinum
• It is covered by mediastinal pleura, which is continuous with visceral pleura at the hilum.

Structures Located at the Root

• Pulmonary artery
• Superior and inferior pulmonary veins
• Main bronchus
• Bronchial vessels: Arteries and veins (Arteries – one on right side and two on left side)
• Nerves
• Lymphatics
• Bronchopulmonary lymph nodes.

Arrangement of Structures in the Root

Abbreviation: A = Artery; B = Bronchus; V = Vein

Question 4. Write a short note on bronchopulmonary segments.
Answer:

Bronchopulmonary Segments

• Bronchopulmonary segments are areas of lung supplied by a single segmental bronchus.
• Each segmental bronchus is accompanied by a branch of pulmonary artery.
• The artery lies in the dorsolateral aspect of the bronchus

• The bronchopulmonary segment is functionally independent and is a well-defined anatomical and surgical segment of the lung
• That is, it is the smallest area of lung that can be removed surgically without affecting adjacent areas of the lung
• There are 10 bronchopulmonary segments for each lung
• Each segment has a shape of an irregular cone
• It has:
  • Apex: Present at the origin of segmental bronchus
  • Base: Directed towards the surface of the lung
• Contents:
  • Segmental bronchus
  • Segmental artery
  • Autonomic nerves
  • Lymphatics
• Bronchopulmonary segments are drained by a segmental vein, which lies in the connective tissue between adjacent bronchopulmonary segments
• Pulmonary veins runs between two segmental bronchus and thus drains more than one segment.

 

Bronchopulmonary Segments Applied Anatomy

Normally infection of bronchopulmonary segments remains confined to it, but tuberculosis can spread from one segment to another.

Lungs Multiple Choice Questions

Question 1. Above the hilum of right lung, we find all except:

1. Pulmonary artery and bronchial artery
2. Bronchus
3. Pulmonary vein
4. Arch of aorta

Answer: 4. Arch of aorta

Question 2. All the following options are true about bronchopulmonary segments except:

1. They are surgically resectable
2. Veins are present in between each segment
3. Pyramidal in shape
4. Secondary bronchus open into them

Answer: 4. Secondary bronchus open into them

Question 3. The right hilum of the lung consists of all the structures except:

1. Pulmonary vein
2. Pulmonary artery
3. Bronchus
4. Inferior vena cava

Answer: 4. Inferior vena cava

Question 4. Which one of the following structures passes posterior to the root of the right lung?

1. Hemiazygos vein
2. Right vagus nerve
3. Right phrenic nerve
4. Thoracic aorta
5. Right recurrent laryngeal nerve

Answer: 2. Right vagus nerve

Question 5. The lung is supplied by:

1. Pulmonary artery
2. Pulmonary vein
3. Bronchial artery
4. All the above

Answer: 3. Bronchial artery