In the larynx there are three cartilages. Both of them are important in protecting the larynx. They have the thyroid cartilage, the cryoicartilage and the epiglottis. So the thyroid and the cryoicartilage support and protect the glottis and the entrance to the shakir. During swallowing the larynx is elevated, the epiglottis folds back over the glottis and this prevents food and fluids from going into the respiratory tract. So just take a moment and take your hand and place it over your shakir and swallow. And you'll feel it moving upwards and if you can visualize it what's happening is that epiglottis, that piece of cartilage is folding back over the glottis to prevent food going down the shakir. You have another drawing of it. You can see that the thyroid cartilage is the big cartilage underneath it. You've got the cryoicartilage and then right up the top of the drawing you've got the epiglottis which is showing up there. The next picture will show you in cross-section. So here again you've got the thyroid cartilage, the cryoicartilage and the epiglottis and is that epiglottis that moves backwards and forwards when we swallow to cover the shakir to prevent any food or fluids going down the shakir. The vestibular ligaments lie within the vestibular folds and they protect the vocal folds. And with the vocal folds which are what also known as your vocal cords was air passing through the glottis it vibrates these vocal folds and it produces sound. Here we've got and drawing of it as if you were able to open your mouth widely and look down. So you've got the anterior and posterior, if you can get your orientation that way and you've got the root of the tongue and there you've got the epiglottis which is now covered with pink tissue. You've got the vocal folds which are open, the glottis is open and you can see the the few round or curved areas of pink ridges that's the beginning of the trachea and here we've got air moving down the trachea and the glottis is open. In this picture same thing but here we have the glottis is closed and no air can move in and no sound can be produced. Here we have a photograph showing you from a person who's having a laryngeoscope passed down that you've got a little camera and this will be passed down through the mouth, down past the vocal cords and down can be passed down a bit further but it provides visualization for the anithetus to be able to pass a tube that will be either going through the person's nose or through their mouth and it will go down into the trachea and there will be secured with a little balloon of air and that tube will be able to provide air moving in and out if the patient is having an anithetic. So the anithetic gases moving in and out through there and the anithetic gases pass through the aviol I'm membrane into the blood supply and keep the patients sedated.