According to http://www.ou.org/kosher/primer.html...
Only a trained kosher slaughterer (shochet) whose piety and expertise have been attested to by rabbinic authorities is qualified to slaughter an animal. The trachea and esaphagus of the animal are severed with a special razor-sharp, perfectly smooth blade causing instantaneous death with no pain to the animal.
After the animal has been properly slaughtered, a trained inspector (bodek) inspects the internal organs for any physiological abnormalities that may render the animal non-kosher (treif). The lungs in particular, must be examined to determine that there are no adhesions (sirchot) which may be indicative of a puncture in the lungs. If an adhesion is found, the bodek must examine it carefully to determine its kashruth status.