27.8
Tongue
The human tongue is a fascinating and complex organ, responsible for various essential functions such as swallowing, speech, and taste. It is also sub…
The tongue, an accessory digestive organ, forms the floor of the oral cavity and extends into the oropharynx.
It is composed of two types of skeletal muscles—intrinsic and extrinsic—encased in a layer of mucous membrane.
Intrinsic tongue muscles, which have no bone attachment, are located entirely within the tongue and aid in shaping it for speech and swallowing.
The extrinsic muscles originate from the skull bones and soft palate, extend to the tongue, and help the tongue change its position.
The lingual frenulum, a mucosal fold, anchors the tongue to the floor of the mouth and limits its backward movement.
The median sulcus divides the tongue into two symmetrical halves on the surface.
In addition to its roles in gustation and speech, the tongue shapes chewed food into a swallowable bolus and pushes it down to the pharynx.
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Q1: What muscles make up the tongue and what do they do?
The tongue contains eight muscles divided into two types. Intrinsic muscles, located entirely within the tongue, change its shape for speech and swallowing. Extrinsic muscles originate from skull bones and the soft palate, extending to the tongue to control its position and gross movements like protrusion, depression, elevation, and retraction.
Q2: How does the tongue help with swallowing?
The tongue shapes chewed food into a swallowable bolus and propels it into the pharynx during swallowing. This coordinated action of intrinsic and extrinsic muscles is essential for moving food from the oral cavity to the esophagus, initiating the swallowing process.
Q3: What is the lingual frenulum and what is its function?
The lingual frenulum is a mucosal fold that anchors the tongue to the floor of the mouth. It limits backward movement of the tongue, helping control its position. When the frenulum is too short, a condition called ankyloglossia or tongue-tie can restrict tongue movement and affect feeding and speech.
Q4: What are the different types of papillae on the tongue?
The tongue has four papilla types: filiform papillae, the most numerous, provide texture but lack taste buds; fungiform papillae are mushroom-shaped and contain taste buds; circumvallate papillae are large bumps at the back containing taste buds; foliate papillae on the sides also contain taste buds for perceiving sweet, salty, sour, bitter, and umami tastes.
Q5: How is the tongue anatomically divided?
The tongue divides into two symmetrical halves along the median sulcus on its surface. It also separates into the anterior oral part, the mobile front two-thirds visible in the mouth, and the posterior pharyngeal part, the fixed back one-third toward the throat. The base connects to the hyoid bone, mandible, styloid processes, and pharynx.
Q6: What role does the tongue play in speech?
The tongue is essential for articulation and speech production. It modulates airflow through the mouth to produce different sounds. Intrinsic muscles change the tongue's shape, while extrinsic muscles control its position, allowing precise movements necessary for clear speech and sound formation.
Q7: What is the relationship between the tongue and taste perception?
Taste buds housed within fungiform, circumvallate, and foliate papillae on the tongue enable gustation. These sensory structures allow perception of five basic tastes: sweet, salty, sour, bitter, and umami. The tongue's position and movement also help distribute food across taste receptors for optimal flavor detection.