Pharynx and Soft Palate Flashcards
Pharynx
The pharynx is a vertically oriented funnel-shaped half-cylinder and serves as the passageway for both air and food.
Boundaries of the Pharynx
- It is suspended in the midline from the basal surface of the occipital bone (pharyngeal tubercle) by its submucosal layer (pharyngobasilar fascia).
- Proximally, it is the direct continuation of the nasal and oral cavities.
- Distally, it leads into the larynx before continuing as the esophagus
Transition from Pharynx to Esophagus
This transition occurs anteriorly at the level of the cricoid cartilage and posteriorly at the level of the C6 vertebrae.
Divisions of the Pharynx
The pharynx is divided into three regions:
• Nasopharynx - posterior to the posterior nasal apertures (choanae) of the nasal cavities
• Oropharynx - posterior to the fauces of the oral cavity
• Laryngopharynx - posterior to the larynx
Functions of the Pharynx
- Deglutition (swallowing)
- Respiration
- Speech
Deglutition
Material passes from the mouth to the esophagus by way of the pharynx
Respiration
Air passes from the nasal cavity (or mouth) to the trachea/lungs by way of the pharynx
Speech
- Air passes from the larynx / vocal cords to the mouth by way of the pharynx
- Sound resonates within the pharynx and be altered
Structures Involved in Deglutition
- Mouth, cheeks, tongue, teeth
* salivary glands, palate and pharynx
Goals of Safe Deglutition
- Bolus formed - prevent dispersion
- suitable size & consistency
- Differential pressures must develop for aboral propulsion
- Prevent entry of food into nasopharynx & larynx
- Suspend respiration while food is passing
- Rapid passage of food
Structures Involved in Respiration
- Nares, nasal cavities
- Nasopharynx
- Oropharynx
- Associated glands
Goals of Safe Respiration
- Remove particulate matter!
- Warm, humidify and cleanse air
The airway and the foodway cross in the oropharynx
Structures Involved in Speech
- Lungs & larynx
- Nasal cavities and sinuses
- Nasopharynx
- Oropharynx
- Associated glands
Production of Speech
• Source of energy: elastic recoil of lungs moves air
• Oscillation of vocal cords
• Resonator – depends on size and shape of:
a) pharynx
b) oral cavity
c) nasal cavity
d) paranasal sinuses
Tissue Layers of the Pharyngeal Wall
From interior to exterior: • Mucosa • Submucosa (pharyngobasilar fascia) • Muscular layer • Buccopharyngeal fascia (Exterior)
Mucosa
The innermost layer has pharyngeal glands (mixed salivary glands)
• Nasopharynx: pseudostratified ciliated epithelium (respiratory type)
• Oropharynx and laryngopharynx: stratified squamous epithelium
Submucosa (pharyngobasilar fascia)
A strong continuous inner layer of fascia that supports the pharynx (especially where gaps are present between muscles of the pharynx)
Muscular layer
The orientation of the muscular fibers of the 2 layers is opposite the typical GI tract muscular arrangement (inner circular/outer longitudinal)
• Inner layer
• Outer layer
Muscles of Inner Muscular layer
3 longitudinal (elevator) muscles
• palatopharyngeus
• stylopharyngeus
• salpingopharyngeus
Muscles of Outer Muscular layer
Outer layer - 3 circular muscles
• superior constrictor
• middle constrictor
• inferior constrictor