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.
An Untested Ingredient. Since 1960, most birth control pills have contained two types of hormones: estrogen and progesterone. Since 2001, some birth control pills have altered this tried-and-true formula by replacing the traditional form of progestin with a new and different synthesis, called drospirenone.