Pulmonary Surfactant. The force of surface tension in the lungs is so great that without something to reduce the surface tension, the airways would collapse after exhalation, making re-inflation during inhalation much more difficult and less effective. Collapse of the lungs is called alectasis.
Rules for Using Semicolons. A semicolon is most commonly used to link (in a single sentence) two independent clauses that are closely related in thought. When a semicolon is used to join two or more ideas (parts) in a sentence, those ideas are then given equal position or rank. Some people write with a word processor; others write with a pen or pencil. Use a semicolon between two independent clauses that are connected by conjunctive adverbs or transitional phrases.
The semicolon is a mark of punctuation ( ; ) most commonly used to separate independent clauses that share the same general idea(s). The semicolon suggests a closer connection between the clauses than a period does. Semicolons still appear fairly often in academic writing; however, they have fallen out of fashion in less formal kinds of prose. You would do well to keep semicolons at a minimum, advises Associated Press editor Rene Cappon. Unlike many of the other punctuation marks, says Martin Manser, there is no occasion on which the semicolon cannot be replaced by another form of punctuation or sentence construction (Good Word Guide, 2008).