LARYNX / TRACHEA / LUNGS Lecture by:-Prof. Ansari (for BDS students only) 8.04.08 Tuesday 8.30 – 9.30 am

Objectives Parts of the larynx, trachea & lungs. Cartilages of larynx Muscles of larynx Vessels & nerves of larynx Interior of larynx Differences between right & left lungs.

LARYNX It is a part of respiratory passage. Concerned with production of sound- voice apparatus. It is made up of cartilages, paired and unpaired. It has intrinsic and extrinsic laryngeal muscles. The cavity is lined by respiratory epithelium- pseudostratified ciliated columnar epithelium.

Hyoid bone is a U-shaped bone, & the only bone not attached to any other bone. It has a body, 2 lesser cornua and 2 greater cornua. It is connected with the thyroid cartilage by means of thyrohyoid membrane.

CARTILAGES OF LARYNX Paired cartilages are:- Arytenoids, corniculates, and cuneiforms. Unpaired cartilages are:- Thyroid, epiglottis and cricoid.

Muscles of the larynx The extrinsic muscles are sternothyroid, sternohyoid, myelohyoid stylohyoid, omohyoid and geniohyoid. The intrinsic muscles are not visible outside larynx except cricothyroid. All intrinsic muscles are supplied by recurrent laryngeal nerve except cricothyroid which is supplied by external laryngeal nerve. All intrinsic muscles of larynx are adductors of vocal cord except posterior cricoarytenoid muscle which is only abductor of vocal cord.

INTRINSIC MUSCLES OF LARYNX

ENDOSCOPIC VIEW OF LARYNX

VOCAL CORDS ADDUCTION

VOCAL CORDS ABDUCTION

SAGITTAL SECTION OF LARYNX

The interior of larynx For our convenience sake the interior is divided into three areas. From epiglottis to the false vocal cord is the first area…Supraglottic part. The second area is between the true and false vocal cords…Glottic area. The third area is below the true vocal cords…Subglottic area.

The mucosal lining Is pseudostratified ciliated columnar epithelium—respiratory epithelium. On the vocal cords it it stratified squamous non keratinized epithelium. Again it is respiratory epithelium below the vocal cords.

The nerve supply of larynx 1. Internal laryngeal nerve will carry sensation of the glottis and supraglottis. 2. Motor fibers are coming from external laryngeal nerve and recurrent laryngeal nerves. 3. Recurrent laryngeal nerve will carry sensation of the subglottis, and motor fibers to the intrinsic muscles.

NERVE SUPPLY OF LARYNX

RESPIRATORY EPITHELIUM

VESSELS OF LARYNX Superior laryngeal artery is a branch of superior thyroid artery, it supplies the larynx. It accompanies the superior laryngeal nerve and enters the larynx by piercing the thyrohyoid membrane. Inferior laryngeal artery is a branch of inferior thyroid artery. It accompanies the recurrent laryngeal nerve.

INTERNAL LARYNGEAL ARTERY (5)

TRACHEA Trachea is a tube continuous below the larynx, 10-16 cms. It divides at the sternal angle into two bronchi. The two bronchi enters the hilum of the lungs. Trachea is lined by respiratory epithelium.

HISTOLOGY OF TRACHEA

LUNGS Are a pair of respiratory organs covered by pleurae. Lungs are located in the thoracic cavity. Right lung has 3 lobes, where as left lung is having 2 lobes. Right lung has horizontal and oblique fissures, where as left has oblique fissure.

DISEASE LUNG

HISTOLOGY OF LUNGS

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