Mastication & Swallowing Flashcards

Questions and Answers

What is mastication?

Mastication is the preparation of food by chewing for deglutition and digestion.

How does saliva help in food mastication?

Saliva softens and lubricates food.

What are the muscles involved in mastication?

Temporalis, Masseter, Lateral pterygoid, Medial pterygoid, Suprahyoid, Infrahyoid, Buccinator.

What is the mnemonic for the muscles of mastication?

Inform Me To Masticate, Lubricate & Swallow Bolus's. Signup and view all the answers

What are the possible planes of movement of the mandible?

Elevation/Depression, Protrusion/Retrusion, Side to side excursion. Signup and view all the answers

What mandible movements are involved in the opening of the jaws?

Depression and Protrusion. Signup and view all the answers

How does the opening/depression of the mandible occur?

It involves rotation in the lower compartment of the TMJ and translation/gliding of the disc & condyle complex. Signup and view all the answers

How does the further depression and protrusion of the mandible occur?

The hyoid muscles pull the mandible further down and forward. Signup and view all the answers

How does the jaw close?

Through a reverse sequence of gliding and rotational movements involving retrusion and elevation. Signup and view all the answers

What muscles perform jaw closure?

Masseter, Temporalis, and Medial pterygoid muscles. Signup and view all the answers

What is the resting position of the jaw?

The resting position of the jaw when it is relaxed. Signup and view all the answers

How big is the freeway space in resting position?

2-4 mm. Signup and view all the answers

What creates/allows the freeway space?

Muscular balance and proprioceptive feedback. Signup and view all the answers

What is considered the normal or right jaw position?

Class 1, Division 1 protrusion. Signup and view all the answers

Explain lateral deviation.

It is a side-to-side non-identical movement in the left and right TMJ. Signup and view all the answers

How does lateral deviation occur to the left?

The right lateral pterygoid muscle contracts, causing the mandible to rotate and translate down before deviating to the left. Signup and view all the answers

What is the power stroke of the mandible?

The movement from the laterally deviated position back to the midline when the teeth are crunching food. Signup and view all the answers

What muscles are involved in the power stroke?

The left or right pterygoid muscle and the left or right posterior portion of the temporalis muscle. Signup and view all the answers

What is deglutition?

The coordinated action of muscles that sends the prepared food bolus from the oral cavity to the pharynx and then to the esophagus and stomach. Signup and view all the answers

What muscles are involved in deglutition?

Elevators of the mandible, palatoglossus, styloglossus, and intrinsic muscles of the tongue. Signup and view all the answers

How does the food bolus exit the oral cavity proper and enter the pharynx?

The tongue presses onto the palate, reducing the oropharyngeal isthmus, while specific muscles lift the soft palate and close communication between the nasopharynx and oropharynx. Signup and view all the answers

Study Notes

Mastication

Preparation of food involves chewing, breaking larger pieces into smaller ones, enhancing surface area for digestion.
Essential for deglutition (swallowing) and digestion.

Role of Saliva

Softens and lubricates food, facilitating mastication.

Muscles of Mastication

Key muscles include:
- Temporalis
- Masseter
- Lateral pterygoid
- Medial pterygoid
- Suprahyoid
- Infrahyoid
- Buccinator
Mnemonic: "Inform Me To Masticate, Lubricate & Swallow Bolus's."

Mandible Movement

Possible movements:
- Elevation/Depression
- Protrusion/Retrusion
- Side to side excursion.

Jaw Opening Mechanics

Involves depression and protrusion of the mandible.
Initial rotation occurs in the lower compartment of the temporomandibular joint (TMJ) led by the lateral pterygoid muscle.
Following rotation, the upper compartment facilitates gliding of disc and condyle down the articular eminence.

Further Mandible Depression and Protrusion

Achieved through the action of hyoid muscles, particularly anterior suprahyoid muscles.
Posterior suprahyoid and infrahyoid muscles stabilize the hyoid bone.

Jaw Closure

Reverses the opening sequence, involving retrusion and elevation of the mandible.

Muscles Involved in Jaw Closure

Contraction of:
- Masseter
- Temporalis
- Medial pterygoid muscles.

Resting Position

Relaxed state of the jaw where teeth are not constantly occluded.
Freeway space measures 2-4 mm, generated by muscular balance and proprioceptive feedback.

Normal Jaw Position

Classified as Class 1, Division 1 protrusion.
Characterized by the upper first molar's mesialbuccal cusps between the corresponding cusps of the lower molar.

Lateral Deviation

Non-identical side-to-side movement of the mandible involving coordination between the left and right TMJ.

Lateral Deviation to the Left

Right lateral pterygoid muscle contraction causes rotation and forward movement of the right condyle, resulting in left deviation of the mandible.

Power Stroke of the Mandible

Movement from a laterally deviated position back to the midline during chewing.

Muscles Involved in Power Stroke

Pterygoid muscles and the posterior portion of the temporalis on the same and opposite sides.

Deglutition

Coordinated action of tongue, soft palate, mastication, and suprahyoid muscles moving food from the oral cavity to the pharynx, esophagus, and stomach.

Muscles in Deglutition

Teeth stabilization achieved by bilateral contraction of mandibular elevators.
Tongue muscles: palatoglossus, styloglossus, and intrinsic tongue muscles work simultaneously.

Food Bolus Passage to Pharynx

Tongue presses against the palate, reducing oropharyngeal isthmus.
Soft palate lifted by palatopharyngeus, levator veli palatini, and uvulae muscles, closing off nasopharynx.
Suprahyoid muscles elevate the hyoid bone and aid bolus passage.
Pharyngeal muscles elevate the pharynx and larynx, driving food towards the esophagus, while the epiglottis closes the larynx to safeguard the respiratory pathway.

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Description

Test your knowledge on the processes of mastication and swallowing with these flashcards. Learn about the definition, the role of saliva, and the muscles involved in mastication. Perfect for students studying anatomy or nutrition.