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Questions and Answers
The primary function of the larynx in humans is phonation.
The primary function of the larynx in humans is phonation.
False (B)
In keen-scented animals, the epiglottis helps enhance olfaction by protruding above the soft palate.
In keen-scented animals, the epiglottis helps enhance olfaction by protruding above the soft palate.
True (A)
The syrinx is located at the lower end of the trachea in birds and is responsible for phonation.
The syrinx is located at the lower end of the trachea in birds and is responsible for phonation.
True (A)
In mammals, arytenoid cartilages are derived from the caudal halves of a divided cartilaginous bar.
In mammals, arytenoid cartilages are derived from the caudal halves of a divided cartilaginous bar.
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An intranarial larynx is developed in some animals to prevent interruption of respiration during swallowing.
An intranarial larynx is developed in some animals to prevent interruption of respiration during swallowing.
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The glottis is the space between the vocal folds and is responsible for sound production in birds.
The glottis is the space between the vocal folds and is responsible for sound production in birds.
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The aryepiglottic folds are associated with the process of deglutition.
The aryepiglottic folds are associated with the process of deglutition.
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The thyroid, cricoid, and arytenoid cartilages are composed of elastic fibrocartilage.
The thyroid, cricoid, and arytenoid cartilages are composed of elastic fibrocartilage.
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The cricoid cartilage is the only complete cartilaginous ring in the air passage.
The cricoid cartilage is the only complete cartilaginous ring in the air passage.
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The cricothyroid joint allows movement between the thyroid and arytenoid cartilages.
The cricothyroid joint allows movement between the thyroid and arytenoid cartilages.
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The recurrent laryngeal nerve lies immediately in front of the cricothyroid joint.
The recurrent laryngeal nerve lies immediately in front of the cricothyroid joint.
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In humans, the glottis opens in a diamond shape.
In humans, the glottis opens in a diamond shape.
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The superior process of the arytenoid cartilage is attached to the aryepiglottic fold.
The superior process of the arytenoid cartilage is attached to the aryepiglottic fold.
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The posterior cricoarytenoid is solely responsible for adducting the vocal folds.
The posterior cricoarytenoid is solely responsible for adducting the vocal folds.
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The mucous membrane of the larynx is entirely composed of ciliated epithelium.
The mucous membrane of the larynx is entirely composed of ciliated epithelium.
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In quiet respiration, the gap between the vocal folds forms an 8 mm wide triangle at the back.
In quiet respiration, the gap between the vocal folds forms an 8 mm wide triangle at the back.
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The saccule is devoid of mucous glands and it does not lubricate the vocal folds.
The saccule is devoid of mucous glands and it does not lubricate the vocal folds.
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The epithelium over the vocal folds is always ciliated.
The epithelium over the vocal folds is always ciliated.
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The thyroepiglottic muscles assist in approximating the epiglottic to the arytenoid cartilages.
The thyroepiglottic muscles assist in approximating the epiglottic to the arytenoid cartilages.
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The posterior cricoarytenoid muscle originates from the muscular process of the arytenoid cartilage.
The posterior cricoarytenoid muscle originates from the muscular process of the arytenoid cartilage.
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The intrinsic muscles of the larynx include the cricothyroids.
The intrinsic muscles of the larynx include the cricothyroids.
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The stratified epithelium 'climbs over' from the front of the epiglottis to the cricoid cartilage.
The stratified epithelium 'climbs over' from the front of the epiglottis to the cricoid cartilage.
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The lamina propria is very tightly attached over the vocal folds, allowing no swelling.
The lamina propria is very tightly attached over the vocal folds, allowing no swelling.
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Contraction of the transverse arytenoid muscle draws the arytenoid cartilages without rotation.
Contraction of the transverse arytenoid muscle draws the arytenoid cartilages without rotation.
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The cricothyroid muscle is the only laryngeal muscle visible in posterior dissections of the neck.
The cricothyroid muscle is the only laryngeal muscle visible in posterior dissections of the neck.
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The thyroarytenoid muscle opposes the action of the cricothyroid muscle.
The thyroarytenoid muscle opposes the action of the cricothyroid muscle.
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The larynx is pulled upwards beneath the tongue during phonation.
The larynx is pulled upwards beneath the tongue during phonation.
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Tilting of the cricoid arch during cricothyroid muscle action results in lengthening of the vocal folds.
Tilting of the cricoid arch during cricothyroid muscle action results in lengthening of the vocal folds.
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Increased tension of the vocal folds is directly related to their increased length.
Increased tension of the vocal folds is directly related to their increased length.
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Phonation involves movements of the vocal folds to create sounds that vary in pitch, intensity, and quality.
Phonation involves movements of the vocal folds to create sounds that vary in pitch, intensity, and quality.
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The vocal folds have sharp edges at rest and are separated during phonation.
The vocal folds have sharp edges at rest and are separated during phonation.
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The triticeal cartilage is an important component found within the lateral thyrohyoid ligaments.
The triticeal cartilage is an important component found within the lateral thyrohyoid ligaments.
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The thyrohyoid membrane is pierced by the internal laryngeal nerve and superior laryngeal vessels.
The thyrohyoid membrane is pierced by the internal laryngeal nerve and superior laryngeal vessels.
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The epiglottis is attached to the thyroid cartilage via the hyoepiglottic ligament.
The epiglottis is attached to the thyroid cartilage via the hyoepiglottic ligament.
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The cricotracheal ligament connects the lower border of the cricoid cartilage to the first cartilaginous ring of the trachea.
The cricotracheal ligament connects the lower border of the cricoid cartilage to the first cartilaginous ring of the trachea.
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The quadrangular membrane's upper border constitutes part of the larynx inlet known as the aryepiglottic fold.
The quadrangular membrane's upper border constitutes part of the larynx inlet known as the aryepiglottic fold.
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The vocal fold is formed by the free and thickened upper border of the aryepiglottic fold.
The vocal fold is formed by the free and thickened upper border of the aryepiglottic fold.
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The vestibular fold was formerly referred to as the 'false vocal cord'.
The vestibular fold was formerly referred to as the 'false vocal cord'.
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The interarytenoid fissure is located in the posterior midline of the larynx.
The interarytenoid fissure is located in the posterior midline of the larynx.
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The rima of the glottis is bounded anteriorly by the vestibular folds.
The rima of the glottis is bounded anteriorly by the vestibular folds.
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Flashcards
Larynx
Larynx
A respiratory organ located between the pharynx and trachea.
Function of the Larynx
Function of the Larynx
Provides a protective sphincter at the air passage inlet, not primarily for sound.
Arytenoid Cartilages
Arytenoid Cartilages
Cranial halves of the cartilaginous bars in mammals' larynx.
Thyroid Cartilage
Thyroid Cartilage
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Epiglottis
Epiglottis
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Intranarial Larynx
Intranarial Larynx
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Aryepiglottic folds
Aryepiglottic folds
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Skeletal framework of the larynx
Skeletal framework of the larynx
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Single cartilages of the larynx
Single cartilages of the larynx
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Pairs of cartilages
Pairs of cartilages
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Cricothyroid joint
Cricothyroid joint
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Vocal folds
Vocal folds
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Thyrohyoid membrane
Thyrohyoid membrane
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Median thyrohyoid ligament
Median thyrohyoid ligament
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Cricotracheal ligament
Cricotracheal ligament
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Quadrangular membrane
Quadrangular membrane
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Cricovocal membrane
Cricovocal membrane
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Rima of the glottis
Rima of the glottis
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Ventricle of the larynx
Ventricle of the larynx
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Epiglottic ligaments
Epiglottic ligaments
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Posterior Cricoarytenoid
Posterior Cricoarytenoid
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Vocal Processes
Vocal Processes
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Rima Glottis
Rima Glottis
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Intrinsic Muscles of the Larynx
Intrinsic Muscles of the Larynx
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Phonation
Phonation
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Excess Swelling in Glottis
Excess Swelling in Glottis
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Aryepiglottic Muscle
Aryepiglottic Muscle
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Thyroepiglottic Muscle
Thyroepiglottic Muscle
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Vocal Fold Epithelium
Vocal Fold Epithelium
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Ciliated Epithelium
Ciliated Epithelium
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Lateral Cricoarytenoid
Lateral Cricoarytenoid
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Transverse Arytenoid
Transverse Arytenoid
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Cricothyroid Muscle
Cricothyroid Muscle
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Thyroarytenoid
Thyroarytenoid
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Vocalis Muscle
Vocalis Muscle
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Protection during Swallowing
Protection during Swallowing
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Intrinisic Movements of Larynx
Intrinisic Movements of Larynx
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Study Notes
Larynx - Respiratory and Protective Organ
- The larynx is a respiratory organ located within the respiratory tract, situated between the pharynx and trachea.
- It sits below the hyoid bone, in the midline of the neck. The most visible part is the laryngeal prominence (Adam's apple).
- The larynx extends backward into the laryngeal portion of the pharynx, where the larynx's inlet is situated.
- The larynx connects to the trachea at the level of the C6 vertebra.
Larynx - Comparative Anatomy
- The larynx's primary function is protection, acting as a sphincter at the air passage inlet, not primarily for phonation, though this is a crucial function in humans
- Lungfish have the simplest larynx, a muscular sphincter surrounding the air passage.
- Improvements include dilator fibers, cartilage bars (later divided into halves), arytenoid cartilages, and a cricoid ring.
- An anterior thyroid cartilage provides shielding.
- Birds use the rima glottis to close the air inlet (silent), but produce sound via a syrinx at the lower trachea.
- Keen-scented animals developed an intranarial larynx, with the epiglottis protruding above the soft palate, to avoid swallowing interrupting respiration. Epiglottis in other animals is for olfaction, not in humans.
- Animals with intranarial larynges and swallowing liquids have mucous folds forming lateral gutters, providing food channels alongside epiglottis/laryngeal aperture, used for deglutition without interrupted breathing. These modifications aid swallowing and respiration.
- Aryepiglottic folds help with deglutition.
- The epiglottis safeguards the larynx inlet during swallowing.
Larynx - Skeleton
- The larynx's skeletal framework includes:
- Three single cartilages (thyroid, cricoid, epiglottic)
- Three paired cartilages (arytenoid, corniculate, cuneiform)
- Three paired joints (cricothyroid, cricoarytenoid, arytenocorniculate)
- Extrinsic ligaments/membranes (thyrohyoid, cricotracheal, hyoepiglottic, thyroepiglottic)
- Intrinsic ligaments/membranes (quadrangular membrane, cricothyroid ligament, cricovocal membrane)
- The vocal folds (vocal cords) are made predominantly from the cricothyroid ligament (cricovocal membrane).
Larynx - Cartilages
- Thyroid, cricoid, and arytenoid cartilages are made of hyaline cartilage (may calcify/ossify with age).
- Epiglottic, corniculate, and cuneiform cartilages are made of elastic fibrocartilage.
- The thyroid cartilage consists of two laminae forming the Adam's apple; superior and inferior horns articulate with the cricoid.
- The cricoid cartilage is a complete ring (only one), acting as the larynx's foundation. It articulates with structures such as the thyroid & arytenoid cartilages.
- The epiglottic cartilage is leaf-shaped, attached to the hyoid & thyroid cartilage to overhang the laryngeal vestibule.
- The arytenoid cartilages are pyramid-shaped, articulating with the cricoid, anchoring vocal folds & laryngeal muscles. They have a vocal process (attached to vocal fold) and a muscular process (attached to cricoarytenoid muscles). Corniculate and cuneiform cartilages attach to these, and related structures.
Larynx - Joints
- Cricothyroid joint: Synovial, allows rocking movements, the recurrent laryngeal nerve lies immediately behind.
- Cricoarytenoid joint: Synovial, lax, allows rotary and gliding movements. The shape of the joint surfaces varies by species. In humans, gliding movements of the arytenoids produce a V-shaped glottis, while rotations create a diamond form.
- Arytenocorniculate joints: Tiny, insignificant (synovial or fibrous).
Larynx - Ligaments and Membranes
- Extrinsic membranes connect the larynx to surrounding structures.
- Thyrohyoid membrane connects thyroid to hyoid; contains triticeal cartilage and is perforated by the internal laryngeal nerve and superior laryngeal vessels.
- Hyoepiglottic ligaments attach epiglottis to hyoid.
- Thyroepiglottic ligaments attach epiglottis to thyroid,
- Cricotracheal ligaments connect cricoid to trachea.
- Intrinsic membranes are within the larynx.
- Quadrangular membrane connects arytenoid, corniculate, and epiglottis; its upper border is the aryepiglottic fold.
- Cricothyroid ligament (or cricovocal membrane) connects cricoid and thyroid cartilages; the upper border forms the vocal fold (vocal cord).
Larynx - Cavity
- The laryngeal inlet communicates with the pharynx, bounded by the epiglottis, aryepiglottic folds, and interarytenoid fissure.
- The lower portion, extending from the inlet to the vestibular folds, contains the vestibule.
- Between the vestibular and vocal folds is the laryngeal ventricle (sinus). A small pouch (laryngeal saccule) is seen anterior to this ventricle.
- The rima of the glottis is a slit-like opening through which air passes. The anterior 60% is intermembranous (bound by vocal folds), posterior 40% is intercartilaginous (vocal process of arytenoids). Resting state glottic opening is a triangle, approximately 8mm wide in the back, with vocal processes parallel, and about 23mm wide in males and 17mm in females.
- The infraglottic part extends from the glottis to the cricoid's lower border to connect to the trachea.
Larynx - Mucous Membrane
- The larynx, as part of the respiratory tract, has pseudostratified columnar epithelium.
- The epiglottis's anterior surface, not inside the larynx's cavity, has stratified squamous epithelium with glands; the posterior epiglottis and aryepiglottic folds have stratified epithelium in places before transitioning to ciliated areas, without a constant boundary.
- Vocal folds have stratified squamous epithelium due to friction avoidance; mucous glands are concentrated in the saccule to lubricate vocal folds.
- Lamina propria is loose except over vocal folds, allowing swelling, potentially causing glottic obstruction.
Larynx - Intrinsic Muscles
- The intrinsic muscles are grouped as inlet and vocal fold movers.
- Inlet sphincter muscles include aryepiglottic and oblique arytenoid in conjunction with transverse arytenoid and often thyroepiglottic.
- Vocal fold movers include posterior cricoarytenoid, lateral cricoarytenoid, thyroarytenoid (with vocalis), transverse arytenoid & cricothyroid.
Detailed explanations of individual muscles are provided in the text (including diagrams).
Larynx - Extrinsic Muscles
- The larynx elevates during swallowing, then returns due to elastic recoil of the trachea.
- Elevators, such as mylohyoid, digastric, stylohyoid, geniohyoid (acting upon hyoid indirectly affects larynx), thyrohyoid, stylopharyngeus, salpingopharyngeus, palatopharyngeus (or stylolaryngeus, salpingolaryngeus, palatolaryngeus respectively – action on larynx), and the inferior constrictor.
- Depressors, such as sternohyoid, omohyoid, and sternothyroid, (acting upon hyoid bone indirectly affects larynx).
- Some actions of the oesophagus aid in returning larynx to resting position.
Larynx - Development
- The larynx develops from the tracheobronchial groove in the primitive pharynx, with cartilages from fourth and sixth arches.
- Origin of other muscles are generally uncertain.
Larynx - Surgical Considerations
- An emergency laryngotomy, preferred over tracheotomy, involves an incision through the cricothyroid ligament.
- This area is used for minitracheal tube insertion, not as primary airway.
Larynx - Blood Supply, Lymphatics, and Nerve Supply
- Extensive detail on the supplying blood vessels (superior laryngeal and inferior laryngeal branches of superior and inferior thyroid arteries respectively) and nerves (recurrent laryngeal, external laryngeal nerves), lymph drainage, and mechanisms of vocal fold movement is explained, including paralysis effects.
Larynx - Functions
- Swallowing: Protection via the aryepiglottic muscles and epiglottis (which tilts back for temporary lid).
- Respiration: Minimal movement during quiet respiration. (Greater abduction for maximum air passage)
- Phonation: Sound production involving vocal fold vibration, modified pitch/intensity/quality determined by various factors and muscle actions. (Vocal fold vibration determined by length/tension/shape and various muscle pairings).
- Muscular effort: Vocal fold closure for heavy lifting, coughing, abdominal straining.
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Description
Test your knowledge on the anatomy and functions of the larynx as a key organ in the respiratory system. This quiz covers its location, structure, and comparative features across species. Find out how the larynx protects the airway and its role in producing sound.
