The respiratory system is divided into four components: the upper respiratory system, lower respiratory system, chest wall and diaphragm. Upper respiratory system: The upper respiratory system comprises all structures and passages involved in the conduction of air from outside the body to the larynx. This system includes the nose, mouth and structures within the hypopharynx.
These 10 animal facts will amaze you. There are two fundamentally different types of laser eye surgery: PRK and LASIK. Under these two categories, there are several different flavors or modifications of each type. For example, LASEK (with an E) is a newer type of PRK.here are two fundamentally different types of laser eye surgery: PRK and LASIK. Under these two categories, there are several different flavors or modifications of each type.
The two main types of eyelid surgery procedures are upper eyelid surgery and lower eyelid surgery. 1  Upper Eyelid Surgery: As the name suggests, this procedure addresses the drooping or sagging of the upper eyelids.  Lower Eyelid Surgery: Used to address puffiness or bagginess under the eyes.