Question

Describe the anatomy and histology of the lungs

Answer 1

Anatomy of lungs :-

• Human lungs are a pair of spongy organ located in the mediastinum of thoracic cavity for gaseous exchange.
• There are two surfaces : coastal and mediastinal surface.
• Three borders:- Anterior, posterior, and inferior
• There is an apex and base for the lungs.
• Right lung has 3 lobes , superior , inferior, and middle.
• Left lung has 2 lobes superior and inferior.
• There is an oblique fissure for left lung and  oblique and horizontal fissure for right lung.
• Blood supply of lungs :-

1. Pulmonary trunk --> Right and left pulmonary arteries --> superior and inferior pulmonary arteries.
2. Intercostobronchial trunk and thoracic aorta--> right and left bronchial arteries .
3. Capillary network veins of Pulmonary venous Circulation.

• Nerve supply of lungs :- Pulmonary plexus (vagus nerve , cervical cardiac nerves.)

Histology of lungs

• Each bronchus branches into narrower bronchiole which is lined by  ciliated cuboidal epithelium and consist of thin layer of smooth muscle.
• As opposed to upper parts of respiratory tracks , it lacks hyaline cartilage.
• The main cells in bronchiole are basal cells, neuroendocrine cells, ciliated cells, serous cells, Clara cells and goblet cells.
• Goblet and clara cells as decrease is number and approach terminal bronchioles.
• There are two types of cells in alveoli are :- type I and type II pneumocytes (alveolar cells) ,
• Type II pneumocytes produce , surfactant,which reduces to lower surface tension of lungs.