Quick Answer. The function of the cartilaginous rings of the trachea is to stabilize the trachea and keep it rigid while allowing the trachea to expand and lengthen when the person breathes. If the trachea was not supported in this way, it would simply collapse because of the pressure of the chest.
1 The Pill. The pill is the common name for oral contraception. It's one of the safest, most effective, and popular methods of birth control. The pill is made up of synthetic forms of hormones that naturally occur in a female's body - progestin and estrogen.
The most common side effect is breakthrough bleeding. A 1992 French review article said that as many as 50% of new first-time users discontinue the birth control pill before the end of the first year because of the annoyance of side effects such as breakthrough bleeding and amenorrhea.