3.5.1) Cystic fibrosis is a chronic degenerative disease (never get better). It is a genetic metabolic disease which leads to a decrease in secretion in various organs, but mostly in the airways. 

Dornase-alfa is used to treat Cystic fibrosis by hydrolysing the proteins in the bronchial mucus to improve fluidity of the mucus to make it easier to remove. 

3.5.2) NRDS is a breathing disorder in new born babies caused by immature lungs. It is more common in premature babies born six weeks or more before their due dates. It usually develops within the first 24 hours after birth.

The general treatment for NRDS involves the use of exogenous surfactants, corticosteroids and other factors such as oxygen and ventilators. The corticosteroids can be administered before birth to the mother to initiate the baby's surfactant production. 

3.5.3) The role of oxygen therapy in NRDS is to ensure oxygenation but the danger with an increase in oxygen for long-term can lead to retinal damage of the baby and also blindness. 

3.5.4)  Neonatal apnoea is when the respiratory centre in the brain is not yet fully developed when the baby is born to stimulate continuous breathing. Methylxanthine is used to treat it because it stimulates the CNS to help with the development of the brain to stimulate continuous breathing, the type of methylxanthine that is used is Theophylline, caffeine.