Anatomy and Physiology of Swallowing – Key Vocabulary

A comprehensive set of vocabulary flashcards covering anatomy, physiology, neural control, and key structures involved in the normal swallow and its coordination with respiration.

Swallowing (Deglutition)

The coordinated process of moving food or liquid from the mouth to the stomach through oral, pharyngeal, and esophageal phases.

Oral Preparatory Phase

Initial stage in which food is taken into the mouth, chewed, mixed with saliva, and formed into a cohesive bolus.

Bolus

A cohesive mass of food or liquid that is prepared for swallowing.

Oral Phase

Stage where the tongue propels the bolus posteriorly toward the oropharynx.

Pharyngeal Phase

Reflexive stage where the swallow response is triggered, the airway is protected, and the bolus is propelled through the pharynx.

Esophageal Phase

Stage in which the upper esophageal sphincter relaxes and the bolus travels through the esophagus to the stomach.

Swallowing Variability

Natural differences in swallow physiology based on bolus characteristics and individual factors such as age and anatomy.

Viscosity

The thickness or flow characteristics of a liquid or semi-solid bolus.

Central Nervous System (CNS)

Brain and spinal cord—central control for voluntary and reflexive aspects of swallowing.

Peripheral Nervous System (PNS)

All nerves outside the CNS; includes cranial and spinal nerves involved in swallowing.

Somatic Nervous System

Voluntary branch of the PNS controlling skeletal muscles, including many swallowing muscles.

Autonomic Nervous System

Involuntary branch of the PNS regulating smooth muscle, glands, and cardiac muscle.

Afferent Pathway

Sensory nerve route carrying impulses from peripheral tissues to the CNS.

Efferent Pathway

Motor nerve route carrying impulses from the CNS to muscles or glands.

Nucleus Tractus Solitarius (NTS)

Medullary sensory nucleus that receives swallow-related input and initiates the motor pattern.

Nucleus Ambiguus (NA)

Medullary motor nucleus sending commands via cranial nerves to pharyngeal, laryngeal, and esophageal muscles.

Cranial Nerves

Twelve paired nerves emerging from the brain; six (V, VII, IX, X, XI, XII) are critical for swallowing.

Trigeminal Nerve (V)

Cranial nerve providing facial sensation and motor innervation to muscles of mastication and hyoid elevation.

Facial Nerve (VII)

Cranial nerve controlling facial expressions, taste to anterior tongue, salivation, lip closure, and hyoid elevation.

Glossopharyngeal Nerve (IX)

Cranial nerve for taste to posterior tongue, gag reflex, salivation (parotid), and pharyngeal constriction.

Vagus Nerve (X)

Longest cranial nerve mediating pharyngeal and laryngeal sensation, vocal fold movement, velopharyngeal closure, and esophageal peristalsis.

Spinal Accessory Nerve (XI)

Cranial nerve assisting velopharyngeal closure and head movement via sternocleidomastoid and trapezius.

Hypoglossal Nerve (XII)

Motor nerve powering intrinsic and extrinsic tongue muscles and contributing to hyoid movement.

Mastication

Chewing process that mechanically breaks down food; powered by trigeminal-innervated muscles.

Temporomandibular Joint (TMJ)

Hinge-and-glide joint between mandible and temporal bone allowing jaw elevation, depression, protrusion, and lateralization.

Temporal Bone

Skull bone housing hearing organs and providing muscle attachments (mastoid, styloid) for swallowing.

Sphenoid Bone

Deep cranial bone with pterygoid plates serving as attachment points for mastication muscles.

Palatine Bone

L-shaped bone forming the posterior quarter of the hard palate.

Maxillary Bone

Paired facial bone forming most of the hard palate, upper jaw, and alveolar ridge.

Zygomatic Bone

Cheekbone that provides origin for part of the masseter muscle.

Mandible

Lower jawbone forming the floor of the oral cavity and articulating at the TMJ.

Tori

Benign bony growths in the oral cavity, typically mandibular or maxillary, usually asymptomatic.

Masseter Muscle

Powerful jaw-closing muscle innervated by CN V.

Temporalis Muscle

Fan-shaped muscle elevating and retracting the mandible; trigeminal innervation.

Medial Pterygoid Muscle

Jaw-closing muscle contributing to grinding; innervated by CN V.

Lateral Pterygoid Muscle

Jaw-opening and protrusive muscle enabling rotary chewing; innervated by CN V.

Orbicularis Oris

Facial muscle encircling the lips; closes, protrudes, and seals the lips during swallowing.

Buccinator

Cheek muscle that flattens cheek and keeps food on the teeth during chewing.

Tongue – Intrinsic Muscles

Muscles within the tongue that change its shape (e.g., lengthen, shorten, curl).

Tongue – Extrinsic Muscles

Muscles originating outside the tongue that position it within the oral cavity.

Hyoglossus Muscle

Extrinsic tongue muscle depressing the tongue; CN XII innervation.

Genioglossus Muscle

Extrinsic muscle protruding and depressing the tongue; CN XII.

Styloglossus Muscle

Extrinsic muscle elevating tongue up and back; CN XII.

Palatoglossus Muscle

Muscle in anterior faucial arch elevating posterior tongue and narrowing fauces; CN X.

Dentition

Set of teeth (32 permanent) that mechanically grind food; absence is called edentulous.

Hard Palate

Bony anterior roof of mouth offering bolus compression surface.

Soft Palate (Velum)

Movable posterior palate that elevates to close the nasopharynx during swallowing.

Salivary Glands

Parotid, submandibular, and sublingual glands secreting saliva for lubrication and digestion.

Parotid Gland

Largest salivary gland, primarily serous, located near the ear; CN IX parasympathetic control.

Submandibular Gland

Mixed serous-mucous gland beneath the mandible; CN VII control.

Sublingual Gland

Predominantly mucous salivary gland under the tongue; CN VII control.

Serous Component (Saliva)

Watery portion of saliva aiding bolus lubrication and enzyme delivery.

Mucous Component (Saliva)

Thick portion of saliva that binds food particles into a cohesive bolus.

Enzymes (Saliva)

Salivary proteins (e.g., amylase) that initiate starch and protein digestion.

Faucial Pillars

Anterior (palatoglossus) and posterior (palatopharyngeus) arches forming oral-pharyngeal boundary.

Vallecula

Space between base of tongue and epiglottis where bolus may pool before swallow.

Pyriform Sinus

Pharyngeal recess lateral to laryngeal entrance that channels bolus toward esophagus.

Upper Esophageal Sphincter (UES)

Cricopharyngeal valve between pharynx and esophagus preventing air entry and reflux.

Lower Esophageal Sphincter (LES)

Distal esophageal valve preventing gastric reflux into the esophagus.

Esophageal Peristalsis

Sequential, wave-like muscular contractions propelling bolus to the stomach.

Laryngeal Vestibule

Entrance to the larynx bounded by epiglottis, aryepiglottic folds, and false vocal folds.

False Vocal Folds

Supraglottic tissue that approximates to help protect the airway during swallow.

True Vocal Folds

Thyroarytenoid muscles that vibrate for voice and close tightly for airway protection.

Penetration

Entry of material into the laryngeal vestibule above the true vocal folds.

Aspiration

Entry of material below the level of the true vocal folds into the airway.

Silent Aspiration

Aspiration without triggering sensation or protective cough response.

Respiration

Physiologic process of gas exchange; includes upper and lower respiratory tracts.

Swallow Apnea

Brief cessation of breathing during pharyngeal swallow to protect the airway.

Exhale–Swallow–Exhale Pattern

Typical coordination where a swallow interrupts exhalation and resumes with exhalation, aiding airway clearance.

Hyoid Bone

U-shaped bone anchoring tongue and elevating during swallowing to assist UES opening.

Inferior Pharyngeal Constrictor

Strongest pharyngeal constrictor composed of thyropharyngeus and cricopharyngeus fibers.

Thyropharyngeus

Upper portion of inferior constrictor that squeezes the pharyngeal walls during swallow.

Cricopharyngeus

Lower portion forming the UES that relaxes to allow bolus entry into the esophagus.

Stylopharyngeus

Longitudinal muscle elevating pharynx and larynx; CN IX.

Salpingopharyngeus

Longitudinal muscle raising pharynx and lowering soft palate; CN X.

Palatopharyngeus

Longitudinal muscle elevating pharynx and narrowing oropharyngeal isthmus; CN X.

Laryngopharynx

Lowest pharyngeal region extending from the hyoid to the esophagus behind the larynx.

Oropharynx

Mid-pharyngeal region behind the oral cavity extending to the hyoid bone.

Nasopharynx

Upper pharyngeal region behind the nasal cavity, separated from oropharynx by the velum.

Cricopharyngeal Segment (Pharyngoesophageal Segment)

Functional zone at the UES formed by cricopharyngeus and adjacent tissues.

Esophageal Glands

Mucous-producing glands lining esophagus to lubricate and protect mucosa.

Laryngeal Airway Protection

Series of events—hyoid elevation, epiglottic inversion, false and true vocal fold closure—that prevent aspiration.

Swallowing Center (Brainstem)

Integrated network in the medulla (NTS & NA) orchestrating the patterned swallow response.

Basal Ganglia

Subcortical nuclei contributing to motor planning and modulation of volitional swallowing.

Cerebellum

CNS structure refining motor coordination and timing of swallowing movements.

Thalamus

Relay station transmitting sensory swallow information to cortical regions.

Medullary Reticular Formation

Region surrounding NTS and NA providing neural circuitry for reflexive swallow sequencing.