Question

The entry of food into the larynx is prevented by
(A) Mitral valve
(B) Diaphragm
(C) Frenulum
(D) Epiglottis.

Answer 1

Hint: Glottis is the opening at the upper part of the larynx.
Larynx: It is also known as sound/voice box because it helps in the production of sound. It is made up of cartilage, present at the upper part of trachea. Its upper part has an opening, ie., glottis. During swallowing this glottis can be covered by epiglottis which is a leaf-shaped cartilaginous structure made up of elastic cartilage.

Complete answer:
Mitral valve :- it is present between the left atrium and left ventricle and has two cusps. It is also known as a bicuspid valve. It prevents the backward flow of blood. It has no role in prevention of larynx. Hence this option is not correct.
Diaphragm :- Role of diaphragm in inspiration: The contraction of muscle fibres of diaphragm causes it to become flat and lowered down thereby increasing the volume of thoracic cavity in anterior-posterior axis. Hence it has no role in preventing entry of food in the larynx. So the option is not correct.
Frenulum :- it is present beneath the tongue. It is a U-shaped structure. It helps in free movement of tongue. It does not play any role in prevention of larynx. Hence this option is not correct.
Epiglottis :- it is a leaf shaped structure. It is a covering or lid of glottis to prevent the entry of food into the larynx during swallowing. Hence this option is correct.

Our required option is d) Epiglottis.

Note: Epiglottis is a single leaf shaped cartilage which projects into the pharynx.
Thus, a total of 9 cartilages 3 paired (ii, iv, v) and 3 unpaired (i, ii, vi).
The thyrohyoid membrane is a broad, flat membrane attached to the hyoid bone above and to the thyroid cartilage below. Inside the larynx are present two pairs of vocal cords, of which one pair is of false vocal cords which have little to do with sound production and the second (inner) pair is of true vocal cords.