Lungs Fissures And Lobes Question And Answers

Lungs

Question 1. What are lungs? Discuss their general features. 
Answer:

Lungs Introduction:

• Lungs (right and left) are organs of respiration.
• They are located in the thoracic cavity one on either side of the mediastinum, enclosed in the pleural sacs.

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• The lungs of children are pink in colour and those of young adults are brown or grey in colour.
• Gradually, they become mottled black due to the deposition of carbon particles inhaled from the atmosphere.
• Lungs are made up of soft, elastic spongy tissue filled with air.

Lungs General features: Each lung is conical and presents

• An apex
• A base
• Two surfaces: Costal and medial
• Three borders: Anterior, posterior, and inferior.

Apex:

• Apex is blunt and projects into the root of the neck about 2.5 cm above the medial 1/3rd of the clavicle. ‘It is covered by the cervical pleura and grooved anteriorly by the subclavian artery.

Base (diaphragmatic surface):

• Diaphragmatic Surface is related to the diaphragm.
• Diaphragmatic Surface  is semilunar and concave due to the upward convexity of the diaphragm.

Lungs Costal surface

• Lungs Costal Surface is large and convex.
• Lungs Costal Surface is related to the ribs and intercostal spaces and bears impressions of ribs and costal cartilages.

Lungs Medial surface

• Lungs Medial Surface contains the hilum of the lung. It is divided into two parts: anterior and posterior.
• Lungs Medial Surface  anterior part is called the mediastinal surface because it is related to the mediastinum.
• Lungs Medial Surface  posterior part is called the vertebral surface because it is related to the vertebral column.

Anterior border:

• Anterior border is thin and shorter than the posterior border. It separates the mediastinal and costal surfaces.
• The anterior border of the right lung is straight, while that of the left lung presents a wide cardiac notch, which is occupied by the heart and pericardium.

Lungs Posterior border:

• Lungs Posterior border is thick and ill-defined.
• Lungs Posterior border separates vertebral and costal surfaces.

Lungs Inferior border:

• Lungs Inferior border is semilunar.
• Lungs Inferior border separates the base from the coastal and medial surfaces.

Question 2. Give a brief account of the fissures and lobes of the lungs.
Answer:

Right lung:  Right lung has two fissures oblique and horizontal.

• Which divides it into 3 lobes:
  1. Upper
  2. Middle
  3. and Lower.

Left lung:  The left lung has only one fissure an oblique tissue.

• Which divides it into two lobes:
  1. Upper and
  2. Lower.

Question 3. Enumerate the difference between the right and left lungs.\
Answer:

These are given in the box below:

Question. What is the arterial supply of the lungs? 
Answer:

These are given in the table and impressions caused by them are given in below.

Structures related to the Mediastinal Surfaces of the Right and Left lungs:

Question 4. What is the arterial supply of the lung 
Answer:

Oxygenated blood: Oxygenated blood to the lungs is supplied by the bronchial arteries

1. On the right side, there is only one bronchial artery, which arises from a right third posterior intercostal artery or left upper bronchial artery
2. On the left side, there are two bronchial arteries: upper and lower, which arise from the descending thoracic aorta

Deoxygenated blood: Deoxygenated blood to the lungs is supplied by the pulmonary arteries.

Question 5. Define the hilum and root of a lung. 
Answer:

The hilum of the lung is a depressed bare area on its mediastinal surface, through which structures enter and leave the lung. The structures entering and leaving the hilum together form the root of the lung.

Question 6. Write a short note on the root of the lung.
Answer:

• Root Of The Lung is a short broad pedicle, which connects the lung to the mediastinum.
• Root Of The Lung consists of all structures that enter or leave the lung through its hilum.
• Root Of The Lung is enclosed in tubular sheath pleura – the cuffofpleura.
• Root Of The Lung lies opposite to the bodies of T5, T6, and T7 vertebrae.

The Root of the Lung Contents:

• Single bronchus (left principal bronchus) in the left lung root and two bronchi, i.e., two branches of the right principal bronchus (eparterial and hypaethral) in the right lung root
• Pulmonary artery
• Pulmonary veins (superior and inferior)
• Single bronchial artery on the right side and two (upper and lower) bronchial arteries on the left side
• Lymph vessels
• Bronchopulmonary lymph nodes
• Bronchial veins
• Pulmonary nerve plexuses
• Loose areolar tissue

Arrangement of structures in the roots of lungs:

From before backward (same on two sides):

• Superior pulmonary vein
• Pulmonary artery
• Bronchus

From above downward (different on two sides) as given in the box below:

Question 7. Enumerate the relations of the root of the lung.
Answer:

Root Of The Lung Anterior (common on two sides):

• Phrenic nerve
• Pericardiophrenic vessels
• Anterior pulmonary plexus

Root Of The Lung  Posterior (common on two sides):

• Vagus nerve
• Posterior pulmonary plexus

Root Of The Lung  Inferior (common on two sides): Pulmonary ligament

Superior:

• Arch of Azygos vein on the right side.
• Arch of the aorta on the left side.

Question 8. Describe the bronchopulmonary segments in brief under the following headings:

1. Bronchopulmonary Segments Definition
2. Bronchopulmonary Segments Characteristic features
3. Bronchopulmonary Segments Number of segments in the right and left lungs and
4. Bronchopulmonary Segments Applied anatomy

Answer:

1. Bronchopulmonary Segments Definition:

It is a structural and functional unit of the lung parenchyma aerated by a segmental (tertiary) bronchus.

2. Bronchopulmonary Segments Characteristic features: It is pyramidal with an apex pointing toward the hilum and a base towards the surface of the lung.

• Bronchopulmonary Segments is surrounded by loose connective tissue.
• Bronchopulmonary Segments  is supplied by the tertiary (segmental) bronchus, segmental branch of the pulmonary artery, and segmental branch of the bronchial artery.
• Bronchopulmonary Segments is drained by intersegmental veins, present in the loose connective tissue of intersegmental planes.

3. Number of bronchopulmonary segments in the right and left lungs:

The right lung consists of 10 segments, whereas left lung consists of 9 segments as given in the box below:

Right lung:

• Right lung Superior lobe: 1, apical; 2, posterior; 3, anterior.
• Right lung Middle lobe: 4, lateral; 5, medial.
• Right lung Inferior lobe: 6, superior (apical); 7, medial basal; 8, anterior basal; 9, lateral basal; 10, posterior basal.

Left lung:

• Left lung Superior lobe: 1, apical; 2, posterior; 3, anterior; 4, superior lingular; 5, inferior lingular.
• Left lung Middle lobe: Absent.
• Left lung Inferior lobe: 6, superior (apical); 7, anterior basal; 8, lateral basal; 9, posterior basal.

Note: The medial basal segment is absent in the left lung.

4. Bronchopulmonary Segments Applied anatomy

• Segmental Resection: Each segment can be delineated by bronchography.
  • If the pathological lesion (such as bronchogenic carcinoma) is confined to one segment, that segment can be removed surgically (segmental resection).
  • The localization of the bronchopulmonary segment by the bronchoscopy also helps in the postural drainage of the lungs.
• Lung Abscess:
  • It is more common in the posterior segment of the upper lobe and apical segment of the lower lobe especially on the right side because aspiration pneumonia is common in these segments.
  • This is because these segments are the most dependent in a recumbent position.