Darshana Bora1, Annie Doley2, Jyotirmayee Lahon3

The lungs are the essential organ of respiration. Maturation of lung is divided into four stages pseudoglandular, canalicular, terminal sac and alveolar. By 16 weeks, all major elements have formed except those involved with gas exchange. Respiration is not possible; hence, foetuses born during this period are unable to survive. By 26 weeks, the terminal sacs are lined by squamous epithelial cells and scattered among them are round secretary epithelial cells, which secrete surfactant. Respiratory distress syndrome affects 2% live newborn infants, premature are more susceptible. Surfactant deficiency is the major cause of RDS. Sufficient alveolar sac and surfactant should be present to permit survival of a prematurely born infant. Keeping this in view, the present study was done to study the microstructure of lungs in different age groups.
The study was carried out in the Department of Anatomy, Assam Medical College and Hospital, Dibrugarh, for a period of one year. The study was carried out in specimens, which was collected from adult cadavers obtained for routine dissection of undergraduate students and also from the Department of Forensic Medicine. Specimens was also collected from perinatal cadavers from the Department of Obstetrics and Gynaecology, Assam Medical College and Hospital, Dibrugarh. The study has been carried out on three primary groups- Group 1, Group 2 and Group 3 according to the age.
In each of the groups, we have studied the right-sided and left-sided lungs separately and studied their histological parameters (presence/absence of pseudostratified columnar, columnar, cuboidal and squamous epithelium in the bronchial tree (lung). The results and observations obtained in the present study are compared with established findings of other workers.
Foetuses born prematurely at 24 to 26 weeks after fertilisation may survive if given intensive care; however, they suffer from respiratory distress because of surfactant deficiency produced by type II pneumocytes in alveoli.