Pharynx & Larynx - Gross Anatomy

Summary

This video provides a detailed overview of the anatomy of the pharynx and larynx. It covers the composition, subdivisions, muscles, and neurovascular patterns of these structures, as well as their clinical significance. The pharynx, serving both digestive and respiratory functions, is divided into the nasopharynx, oropharynx, and laryngopharynx. The larynx, known as the voice box, produces sound and protects the airway during swallowing. The video further explores the muscles, cartilages, innervation, blood supply, and clinical applications such as swallowing and foreign body obstruction, offering a comprehensive guide to this complex area of anatomy.

Takeaways

• 😀 The pharynx is a shared passageway for food and air, connecting the nasal cavity, oral cavity, larynx, and esophagus.
• 😀 The pharynx is divided into three regions: the nasopharynx, oropharynx, and laryngopharynx, each with unique features.
• 😀 The pharynx is protected by a lymphatic tissue ring known as Waldeyer's Ring, which includes tonsils (pharyngeal, palatine, and lingual).
• 😀 The muscles of the pharynx, including the constrictor muscles and longitudinal muscles, play a role in swallowing and elevating the larynx.
• 😀 The pharynx is innervated by the vagus nerve (cranial nerve 10), except for the stylopharyngeus muscle (innervated by the glossopharyngeal nerve).
• 😀 The larynx functions as both a voice box and an airway, with air passing between vocal folds to produce sound.
• 😀 The larynx is composed of six cartilages, including three unpaired (thyroid, cricoid, and epiglottis) and three paired (arytenoid and corniculate).
• 😀 The thyroid cartilage is the largest, with the laryngeal prominence (Adam's apple) visible in males due to its sharper angle.
• 😀 The larynx is innervated by the vagus nerve, with the recurrent laryngeal nerve innervating most laryngeal muscles.
• 😀 During swallowing (deglutition), the pharynx and larynx work together to prevent food or liquids from entering the airway, with the epiglottis closing over the laryngeal inlet.

Q & A

What are the main functions of the pharynx?

The pharynx conducts food, liquids, and air from the nasal or oral cavities to the digestive or respiratory tracts. It is shared by both the respiratory and digestive systems, functioning as a passageway for both food and air.

What are the three subdivisions of the pharynx?

The pharynx is divided into three regions: the nasopharynx (behind the nasal cavity), the oropharynx (behind the oral cavity), and the laryngopharynx (behind the larynx).

Which muscles form the posterior boundary of the pharynx?

The posterior boundary of the pharynx is formed by three circular muscles: the superior, middle, and inferior pharyngeal constrictor muscles.

How do the pharyngeal constrictor muscles function?

The pharyngeal constrictor muscles contract sequentially from top to bottom to push food down the throat during swallowing.

What role do the tonsils play in the pharynx?

The tonsils, which form the Waldeyer's ring, provide protection against pathogens entering through the nasal and oral cavities. They include the pharyngeal (adenoids), palatine, and lingual tonsils.

What is the function of the epiglottis in the larynx?

The epiglottis functions to protect the airway during swallowing by covering the laryngeal inlet and preventing food from entering the airway.

Which cartilage in the larynx is the only complete ring of cartilage?

The cricoid cartilage is the only complete ring of cartilage in the airway, and it is crucial for maintaining the structure of the airway.

What is the role of the posterior cricoarytenoid muscle?

The posterior cricoarytenoid muscle is the only muscle that abducts the vocal folds, increasing the size of the glottis and thus opening the airway.

What is the clinical relevance of the piriform fossa?

The piriform fossa in the laryngopharynx is clinically relevant because it is a common site for foreign bodies to lodge, and damage to the nerves in this area can lead to serious complications.

How does the vocal fold movement affect voice production?

The tension on the vocal ligaments, which are adjusted by the intrinsic muscles of the larynx, directly influences voice pitch. Increased tension results in a higher pitch, while decreased tension lowers the pitch.