Lecture 10 slides- Physiology of Mastication and Deglutition

Definitions:Mastication?

the process of preparing food for swallowing; chewing

Definitions: Deglutition?

processes of swallowing

Definitions: Bolus?

ball of food or liquid to be swallowed

Definitions: Dysphagia?

Difficulty moving food from the mouth to the stomach

Anatomy of Mastication and Deglutition: Over ____pairs of muscles involved in mastication and deglutition

55

Development of Swallowing: What forms the basis for development of the speech system?

Feeding skills

Gross & reflexive movements become refined and coordinated movements for speech and swallow

Development of Swallowing: Development of swallowing begins well before ___

Birth

Development of Swallowing: Newborns have reflexes to help them feed. What are the two reflexes?

Rooting Reflex: involves light tactile stimulation to the cheek area, which causes an infant to turn their head towards the stimulus and open their mouth

Sucking Reflex: elicited by soft contact with the inner margin of the lips, causing the infant to close their lips and protrusion and retraction of the infant’s tongue in preparation for receiving food from the mother’s breast

Adult vs Infant Oral-Pharyngeal Structures: What are the four infant structures?

Oral cavity smaller

Larynx & hyoid are elevated at birth as compared with the adult

Velum is relatively larger as compared to the pharynx

No teeth

Stages of Mastication & Deglutition: 4 Stages of Mastication & Deglutition?

Oral Stage (mastication)

 Preparatory

 Transport

Pharyngeal Stage (pharyngeal swallow)

Esophageal Stage (esophageal transit)

Stages of Mastication & Deglutition: Oral Preparatory

Food is prepared for swallowing

Tongue forms the liquid or solid into a cohesive bolus after the solid has been chewed and mixed with saliva. •

Bolus is held as a cohesive unit against the hard palate and tongue.

Oral Stage: Oral Preparatory: What muscles are used?

Facial muscles, tongue muscles, Mandibular muscles, soft palate muscles

Oral Stage: Transport:

Lips seal and tongue moves bolus back toward the oropharynx

Oral Stage: Transport: Muscles used

Mandibular muscles and Tongue muscles

 Elevate mandible

Pharyngeal Stage: When does the pharyngeal stage begin, and what happens during this stage?

Swallow response is triggered causing several physiologic activities to occur simultaneously and pushing food from the pharynx into the esophagus.

Pharyngeal Stage: What muscles are used during this stage?

Tongue Muscles, Pharyngeal constrictors(contrsit pharynx, elevate pharynx and larynx), soft palate muscles, laryngeal muscles

Esophageal Stage: What happens during the esophageal stage, and when does it begin?

Food passes, by peristaltic action and gravity, through the esophagus to the stomach.

Esophageal Stage: How does the bolus travel through the esophagus and enter the stomach?

• Esophageal peristaltic motion and gravity carry the bolus through the esophagus.

• The lower esophageal sphincter opens to allow the bolus into the stomach.

Esophageal Peristaltic and Sphincter: Esophageal Peristaltic

Successive waves of involuntary contraction passing along the walls of the esophagus and forcing the bolus onward

Esophageal Peristaltic and Sphincter: Esophageal Sphincter

A ring of muscle that contracts to close an opening

Prepost: What is the correct order of the different phases of a normal swallow from first to last?

. Oral preparatory → Oral transit → Pharyngeal → Esophageal

In what stage does the lower esophageal sphincter open, allowing the bolus to enter into the stomach?

E. esophageal

During the esophageal stage, the bolus travels down the esophagus through peristaltic contractions. The lower esophageal sphincter (LES) relaxes and opens, allowing the bolus to enter the stomach.

PrePost: In what stage does the tongue elevate and squeeze the bolus posteriorly toward the faucial pillars?

D.oral transit

During the oral transit stage, the tongue elevates and presses against the hard palate, pushing the bolus backward toward the faucial pillars and into the pharynx.

PrePost: In which stage does the velum elevate to separate the oral and nasal cavities?

A.pharyngeal

• Oral preparatory → A. Lips sealed, rotary jaw motion, velum depressed.

• Oral transit → B. This stage ends when the bolus reaches the faucial pillars.

• Pharyngeal → D. Vocal folds are closed and respiration ceases.

• Esophageal → C. Bolus enters the esophagus and is moved by peristalsis.

Sensation Associated with Mastication and Deglutition:

Numerous types of stimulus receptors are critical for completion of the chewing, sucking and swallowing (CSS) elements associated with mastication and deglutition

Senses involved in chewing and swallowing : ___

taste (gustation)

smell (olfaction)

touch (tactile sense)

temperature (thermal sense)

pain (nociception)

muscle stretch & tension

Gustation (Taste): Taste receptors (taste buds, taste cells) consist of a class of sensors known as ____ , that respond when____

Found in papillae (prominences) on ___ of tongue

Taste receptors (taste buds, taste cells) consist of a class of sensors known as chemoreceptors, that respond when specific chemicals come in contact with them

Surface, epiglottis, pharynx, esophageal entrance, palate

Taste: 5 main types of taste receptors

Sweet

Salt

Sour

Bitter

Umami (taste of monosodium glutamate (MSG), which tastes “meaty,” or protein-like)

Taste: All are found throughout tongue, but there is some truth in the idea that ___

certain taste sensors are concentrated in different regions

Olfaction (Smell): Smell plays a vital role ___

Olfactory sensors located in ___

Salivation:____

Gagging, vomiting: triggered by ___

in appetite and taste

posterior nasal cavity

triggered by pleasant food odors

Gagging, vomiting: triggered by unpleasant odors

• Mastication → D. Chewing

• Deglutition → A. Swallowing

• Olfaction → C. Smelling

• Dysphagia → B. Difficulty moving food from the mouth to the stomach

• Gustation → E. Tasting

Reflexes: Chewing Reflex

Triggered by deep pressure on the roof of the mouth (palate)

Alternating left-right contraction of mandibular elevators (masseter and medial pterygoid muscles) causes rotary motion of the mandible

Reflexes: Rooting & Sucking Reflexes

Rooting triggered by tactile stimulation to the cheeks or lips and causes infants to turn toward stimulus and open their mouths

Sucking triggered by contact with inner margin of lips and causes infants to close lips and alternating protrusion & retraction of tongue

During which stage does the lower esophageal sphincter open, allowing the bolus to enter into

the stomach?

a) pharyngeal

b) oral preparatory

c) gastrointestinal

d) esophageal

e) oral transi

During the esophageal stage, the lower esophageal sphincter (LES) relaxes and opens, allowing the bolus to enter the stomach.

During which phase of swallowing does the velum elevate to separate the oral and nasal cavities?

a) oral transit

b) esophageal

c) nasal

d) pharyngeal

e) oral preparatory

During the pharyngeal phase, the velum (soft palate) elevates to close off the nasal cavity, preventing food or liquid from entering the nose.