ORAL CAVITY

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Ahmed Abdulwahab UG : (1330095)

Physiological Events I.IngestionII.Mechanical digestionIII.Chemical digestionIV.Propulsion voluntary stage of swallowing

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Physiological Events Ingestion of food is simply voluntarily taking food into the digestive tract through the oral cavity.

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Physiological Events Mechanical Process Mastication

As food enters the oral cavity the cheeks and the closed lips hold food between the teeth, the tongue mixes the food with saliva to soften it, and the teeth cut and grind it into a bolus. Suitable for swallowing

Mastication is both voluntary and partly reflexive.

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Physiological Events Chemical processesChemical digestion of starch is begun by salivary amylase present in saliva. Saliva (1-1,5 liters per day) is a slightly acid solution of salts and organic substances secreted mainly by 3 pairs of salivary glands (parotid, buccal, submandibular glands).

Basic saliva components: Water 99.5% -Ions: Na++, K++, Ca2+2+, Cl Cl ––, HCOHCO33

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Proline -rich proteins for protection of teeth enamel: - Enzymes: ptyalin (from salivary glands),

- lingual lipase (secreted from glands on the tongue). - Immunoglobulins : IgA

- Mucin: glycoproteins for lubrication of food and protection of oral mucosa

- Lysozyme, lactoferrin, thiocyanate ions

pH of saliva is about 7 Salivary flow ranges between 0.5 ml/min during basal flow and 5ml/min during maximum flow

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Cerebral cortex Other inputs

Salivary centerin medulla

Conditionedreflex

Pressure receptorsand chemoreceptorsin mouth

Autonomic nerves

Autonomic nerves

Salivary glands

Salivary secretions

Simple reflex

Physiological Events Other important (non-digestive) functions of saliva: Cleansing – Mouth and teeth kept free of debris, ect. Protection – Leucocytes, the enzyme lysozyme and antibodies act against some bacteria.

Moistening and Lubricating – soft parts of mouth kept pliable for speech. Cells of oral mucosa protected from drying.

Excretory – many organic substance (e.g. urea, sugar) and inorganic substance (e.g. mercury, lead) can be excreted in saliva.

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Physiological Events Propulsion

The voluntary phase of deglutition is initiated by the tongue. The tip of the tongue is place on the hard palate, and then contracts which forces the bolus into the oropharynx.

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The Teeth Definition (teeth): There are two definitions

Primary (deciduous)

Secondary (permanent)

A tooth is made up of three elements:

Water

Organic materials

Inorganic materials

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The Teeth Dentition (teeth): There are two dentitions

Primary (deciduous)

Consist of 20 teeth

Begin to form during the first trimester of pregnancy

Typically begin erupting around 6 months

Most children have a complete primary dentition by 3 years of age

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The Teeth Secondary (permanent)

Consist of 32 teeth in most cases

Begin to erupt around 6 years of age

Most permanent teeth have erupted by age 12

Third molars (wisdom teeth) are the exception;

often do not appear until late teens or early 20s

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The Teeth Classification of Teeth: Incisors (central and lateral)

Canines (cuspids)

Premolars (bicuspids)

Molars

Incisors - Incisors - function as cutting or shearing instruments for food.

Canines - Canines - assess the longest roots of all teeth and are located at the corners of the dental arch.

Premolars -Premolars - act like the canines in the tearing of food and are similar to molars in the grinding of food.

Molars -Molars - are located nearest the temporomandibular joint (TMJ), which serves as the fulcrum during function.

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Oral Cavity Environment

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pH values:

measure of acidity or alkalinity of a solution

measured on a scale of 1-14

pH of 7 indicated that the solution is neutral

pH of the mouth is close to neutral until other factors are introduced

pH is a factor in demineralization and remineralization

The Taste Dissolution in Saliva Attachment to Receptors Generator Potential Action Potential

Primary modalities of taste: Sour- Salt- Sweet- Bitter

umami (deliciousness), a taste associated with glutamate & other nucleotides has receptors located at the back of the pharynx.

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Thank you for your attention AHMED ABDULWAHABGU : (1330095)

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