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 birth control shot, Depo-Provera, is a hormone injection that can prevent unplanned pregnancy. The birth control shot delivers a high dose of the hormone progestin. Progestin is a synthetic version of progesterone, which is a naturally occurring sex hormone in the body. Irregular bleeding is the most common side effect of the birth control shot.