Feeding and Swallowing Midterm

Define motor equivalence (described by Corbin-Lewis/Liss)

Motor equivalence is the ability to accomplish the same motor goal through multiple, flexible combinations of muscle activation and movement patterns rather than a single, fixed sequence.

Name the 4 bolus characteristics that the normal swallow must accomodate

1. Bolus volume

2. Consistency/Viscosity

3. Temperature

4. Taste/Flavor

Name 5 findings that an increase in bolus size is associated with

Longer transit times

Tongue moves earlier

Palate lifts earlier and longer

Hyolaryngeal complex lifts earlier

Longer breath‑hold (apnea)

Name 2 swallowing results as related to higher viscosity

Pharyngeal squeezes last longer

More swallows needed to clear the bolus

Name 2 swallowing results as related to a solid bolus as compared to liquids

Longer transition times between phases

Velum stays up longer

Name a swallow result as related to taste (sour bolus)

Sour bolus may improve oral phase in people with neurogenic dysphagia.

Name one aspect of anatomy/physiology of the swallow that changes with age

Tongue movement slows down and becomes less efficient; oral transit times increase.

What is xerostomia

Dry mouth - it reduces lubrication and impairs bolus formation (makes swallowing harder)

Name some side effects that pharmacology agents may have on swallowing

Xerostomia, nausea, vomiting, anorexia etc.

What is the role of the lateral precentral gyrus as associated with swallowing

Primary motor control for oral, pharyngeal, and esophageal muscles.

What is the role of the lateral postercentral gyrus as associated with swallowing

Detects taste, tracks saliva, and senses feeling in the back of the throat during chewing.

What is the role of the premotor cortex-parietal cortex loop as associated with swallowing

Plans the sequence of swallow movements.

What is the role of the periventricular white matter as associated with swallowing

Helps coordinate tongue movement.

What is the white matter in the brain

Nerve fibers deep in the brain that connect different regions and help them communicate.

In relation to the central sulcus, where is the motor cortex located?

The motor cortex is located anterior (in front of) to the central sulcus

In relation to the central sulcus, where is the sensory cortex located?

The sensory cortex (somatosensory cortex) is located posterior (behind) to the central sulcus

Name 3 important subcortical structures important for sensorimotor control of swallowing

Thalamus, basal ganglia and cerebellum

Describe the thalamus

A deep brain (subcortical) structure that acts as a sensory relay station

Describe the thalamus and its role in swallowing

It relays information about the sensation of eating/swallowing to other brain areas — key part of the sensory (afferent) system.

What are the three parts of the basal ganglia

Caudate nucleus, globus pallidus and putamen

What is the basal ganglia's role in swallowing

It updates and modifies motor output for swallowing.

Where is the cerebellum located in the brain

It's located posteriorly in the brain

What is the cerebellum's role in swallowing

It processes sensory info about the bolus and fine-tunes motor movements to ensure coordination.

What are the current discoveries that have changed how we view the swallow sequence

Swallowing was once thought to be rigid and fixed, but it is actually flexible and adaptable — this is called motor equivalence.

What space is located between the epiglottis and the base of the tongue

Vallecula

The vallecula is found between which two structures

The epiglottis and the base of the tongue

Which structure sits posterior to the base of the tongue

Epiglottis

The epiglottis is located anterior or posterior to the base of the tongue

Posterior

Which structure sits anterior to the base of the epiglottis in the anterior neck

Hyoid bone

Which structure is in the space above the vocal folds and serves as the opening from the pharynx into the airway

Laryngeal vestibule

The laryngeal vestibule is located superior to what structure

The vocal folds

The vocal folds sit inside what structure/cartilage framework

The larynx/cartilages of the larynx

Which folds are located superiorly to the TVF's

False vocal folds

Which structure lies inferior to the larynx and connects it to the lungs

Trachea

Which structure connects the larynx to the lungs

The trachea

T/F: The labeled space between the tongue base and epiglottis is the velum

False! It's the vallecula.

In a sagittal view, which structure would you expect to see anterior in the neck and in front of the epiglottis base

Hyoid bone

If a label points to a structure inside the thyroid cartilage/laryngeal framework, what major structure is a part of

The larynx

The pharyngeal phase of the swallow begins with the onset of the _______________ and ends when the bolus passes through the ___________.

swallow trigger; UES

Is the pharyngeal phase of the swallow primarily reflexive or voluntary

Reflexive

Name the two main objectives of the normal pharyngeal phase of the swallow

Airway protection and bolus propulsion

(T/F) The pharyngeal phase swallow in a normal swallow is triggered by sensory input from the bolus, which is always at the location of the anterior faucial arches

False

T/F: in the pharyngeal swallow phase, swallow trigger, hyolaryngeal excursion, laryngeal protection (vocal fold and epiglottic inversion), pharyngeal constriction, and UES opening, all happen in a discreet, "one-after-the-other" fashion and never happen in any other order

False

Name the 3 muscles that comprise the lateral and posterior pharyngeal walls AND are partially responsible for bolus propulsion through the pharynx

Superior pharyngeal constrictor

Middle pharyngeal constrictor

Inferior pharyngeal constrictor

Name the two boundaries of the esophagus

UES and LES

What muscle fiber is present in the abdominal esophagus

Smooth

What muscle fiber is present in the thoracic esophagus

Mixed

What muscle fiber is present in the cervical esophagus

Striated

T/F: Dysphagia of the esophageal phase may lead to oral and/or pharyngeal deficits/dysphagia

True

What are the two different general groups/types of disorders that esophageal dysphagia may be divided into

Motility and Structural Disorders

Achalasia is caused by dysfunction of what structure?

Lower esophageal sphincter (LES)

What is the inferior border of the esophagus

LES

Volitional control of swallowing is mediated primarily by what?

Cortical brain areas and their connections with subcortical areas

Is volitional swallowing controlled only by the brainstem?

No, it is also mediated by cortical brain areas and their subcortical connections

The motor cortex is located anterior or posterior to the central sulcus?

Anterior

The sensory cortex is located anterior or posterior to the central sulcus?

Posterior

What is located anterior to the central sulcus?

Motor cortex

What is located posterior to the central sulcus?

Sensory cortex

What three major subcortical areas communicate with the brainstem and cortex in swallowing control?

Thalamus, basal ganglia, and cerebellum

Which swallowing-related structures are deep in the cerebral hemispheres?

Thalamus and basal ganglia

Which structure involved in swallowing control is located posteriorly?

Cerebellum

Which structure is considered the "sensory relay station" for swallowing?

Thalamus

The thalamus sends information about what to other cortical and subcortical structures?

Bolus characteristics and circumstances

The thalamus is considered a key player in which system of sensorimotor swallowing control?

The afferent system

What kind of swallowing information does the thalamus help convey?

Information about the sensation of eating and swallowing

If a structure relays sensory information about bolus characteristics, what is it most likely?

The thalamus

Which structure has extensive connections to both cortical and other subcortical structures and is a key part of the efferent swallowing system?

Basal ganglia

The basal ganglia are most strongly associated with the afferent or efferent system of swallowing control?

Efferent

What do the basal ganglia do to cortical and cerebellar output?

Modulate it for motor control

Which structure helps modulate motor output for swallowing rather than primarily serving as a sensory relay station?

Basal ganglia

Which structure closely communicates with the thalamus and basal ganglia and serves as a monitor of afferent swallowing information?

Cerebellum

What structure acts as a corrector of efferent output to make online adjustments to cortical motor output?

Cerebellum

The cerebellum's role in swallowing is best described as what?

Monitoring afferent input and correcting efferent output for online motor adjustments

Which structure fine-tunes swallowing movements by adjusting cortical efferent output during the swallow?

Cerebellum

Do cortical and subcortical structures play a role only in volitional swallowing?

No, they play a crucial role in both automatic and volitional swallowing

Cortical and subcortical areas are important for what two major swallowing functions?

Initiation and fine-tuning of swallowing movements

Sensory pathway information integrates to affect what during swallowing?

Motor output

Why is sensory information important for swallowing motor output?

It helps modify movement to increase safe and efficient swallowing

Cortical input helps modify swallow commands to muscles in what way?

By facilitating efficient, bolus-specific muscle synergies

What happens to primary sensory and motor cortical activity with oral anesthesia?

It is reduced

What happened to submental muscle activation during oral anesthesia in the cited studies?

It became more powerful

Why might swallowing become less efficient when the NTS receives less sensory information?

Because the brainstem swallowing structures respond more blindly and less efficiently

Reduced sensory information to the NTS leads to swallowing that is more or less efficient?

Less efficient

What are the four traditional phases of swallowing?

Oral preparatory, oral, pharyngeal, and esophageal

Are the four phases of swallowing truly completely distinct and separable in real life?

No

The division of oropharyngeal swallowing into stages is considered what?

An artificial conceptualization of a functionally integrated and dynamic system

Why is the 4-phase model considered limited?

Because it does not accommodate all the variation that occurs during normal mealtime eating and drinking

What three major things contribute to swallowing variability?

Motor equivalence, bolus characteristics, and swallower variables

Swallowing was once believed to be what kind of motor activity?

A fixed and rigid motor activity regulated by lower neural activation

Newer evidence suggests swallowing is fixed and rigid or flexible?

Flexible

What does "motor equivalence" mean in swallowing?

A motor goal can be accomplished in different ways depending on the muscles and joints involved

Can a single swallow pattern be generalized to all swallows?

No, the dynamics of a single swallow cannot be extended to multiple swallows

During the oral phase, which movement is relatively stable across motor tasks?

Jaw/mandible movement (masseter activity)

Even though jaw movement is relatively stable, do all other muscles move in one fixed identical pattern?

No

Why is variability in oral motor patterns important?

Because foods vary in characteristics, so swallowing must adapt

In Dua et al. (1997), did the bolus often reach the pharynx before the swallow trigger in normal individuals?

Yes

In Dua et al. (1997), what percentage of solids reached the pharynx before swallow trigger?

76%

In Dua et al. (1997), what percentage of liquids reached the pharynx before swallow trigger?

60%

Nagy et al. (2013) found that spontaneous liquid swallows are commonly triggered where?

In the hypopharynx

Daniels and Foundas (2001) found that the swallow response can be triggered from what multiple pharyngeal sites?

Valleculae, epiglottis, and pyriform sinuses