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LARYNX / TRACHEA / LUNGS

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

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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.

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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.

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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.

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CARTILAGES OF LARYNX

Paired cartilages are:- Arytenoids, corniculates, and

cuneiforms. Unpaired cartilages are:- Thyroid, epiglottis and cricoid.

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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.

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INTRINSIC MUSCLES OF LARYNX

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ENDOSCOPIC VIEW OF LARYNX

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VOCAL CORDS ADDUCTION

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VOCAL CORDS ABDUCTION

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SAGITTAL SECTION OF LARYNX

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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.

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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.

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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.

19NERVE SUPPLY OF LARYNX

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RESPIRATORY EPITHELIUM

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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.

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23INTERNAL LARYNGEAL ARTERY (5)

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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.

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HISTOLOGY OF TRACHEA

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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.

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DISEASE LUNG

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HISTOLOGY OF LUNGS

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