Physiology
of
Mastication and Deglutition
Chapter 8
Perry C. Hanavan, Au.D.
Mastication & Deglutition
Mastication:
• Processes involved in
food preparation,
including moving
unchewed food onto
the grinding surface
of the teeth, chewing,
it, and mixing it with
saliva in preparation
for swallowing
Deglutition:
• swallowing
Stages of Deglutition
Stages of Duglutition
Deglutition
• Disphagia Dr. Steven Feinberg Discusses
Swallowing Disorders
• Normal Deglutition (PPT)
• Videofluoscopy
• Xray
Rooting & Sucking
Root Reflex
Response of infant to
tactile stimulation of
the cheek or lips;
causes infant to turn
toward the stimulus
and open mouth
Suck Reflex
Involves tongue
protrusion and
retraction in
preparation for receipt
of liquid; stimulated
by contact to the
upper lip
Root & Suck Reflex
Other Reflexes
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Babinski
Stepping
Startle reflex
Palmar/grasp reflex
Dive Reflex
Adult vs. Child
Infant vs. Adult
Videoflouroscopy
Stages of Duglutition
Lower Esophageal Sphincter
Herniation of Stomach
Developmental Malformations
A.
B.
C.
D.
E.
Normal esophagus
Esophagus anatomising with trachea
Esophagus stenosis
Esophageal discontinuity with tracheal porting
Esophageal fusing with trachea
Developmental Malformations
GERD
• GastroEsophageal Reflux Disease
– Stomach contents/acids recycled in
esophagus (causing heartburn) and pharynx
and perhaps can be aspirated
– Additional links on GERD
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LapSurg
American Family Physician
The Purple Pill
Reflux Esophagitis
Reflux Laryngitis
Innervations of Tongue
Salivation Glands & Ducts
Gustation and Olfaction
Gustation and Olfaction
• Have you ever wondered why food loses its
flavor when you have a cold?
• It's not your taste buds' fault. Blame your stuffedup nose.
• Seventy to seventy-five percent of what we
perceive as taste actually comes from our sense
of smell.
• Taste buds allow us to perceive only bitter, salty,
sweet, sour and savoury flavors.
• It's the odor molecules from food that give us
most of our taste sensation.
Taste
• Taste drives appetite and protects us from
poisons.
• We like the taste of sugar because we have an
absolute requirement for carbohydrates (sugars
etc.).
• We get cravings for salt because we must have
sodium chloride in our diet.
• Bitter and sour cause aversive, avoidance
reactions because most poisons are bitter (most
bitter substances are bad for you - certainly in
excess) and off food goes sour (acidic).
• We have a need for protein--amino acids are the
building blocks for proteins, so the "new" taste
quality umami (pronounced: oo-marmi) which is
the meaty, savoury taste drives our appetite for
amino acids.
– This taste has been known to the Japanese for a
long time - but has only recently been recognized
by the West.
– Bacon really hits our umami receptors because it is
a rich source of amino acids.
Taste
• In mammals, taste buds are
aggregations of 30-100 individual
elongated "neuroepithelial" cells
(50-60 microns in height, 30-70
microns in width), which are often
embedded in specializations of
surrounding epithelium, termed
papillae.
• At the apex of the taste bud,
microvillar processes protrude
through a small opening, the taste
pore, into the oral milieu.
• Just below the taste bud apex, taste
cells are joined by tight junctional
complexes.
Taste Papillae
• Taste papillae can be seen on the tongue as little red dots,
or raised bumps, particularly at the front of the tongue.
• These are actually called "fungiform" papillae, because
they look like little button mushrooms.
• There are three other kinds of papillae, foliate,
circumvallate and the non-gustatory filiform.
• Taste buds, on the other hand, are collections of cells on
these papillae.
Taste Sensors
Taste
Neurology of Taste
Routing of Taste
Olfaction
• To identify the smell of a rose, the
brain analyzes over 300 odor
molecules.
• The average person can discriminate
between 4,000 to 10,000 different
odor molecules.
• We inhale airborne molecules that
travel to and combine with receptors
in nasal cells.
• The cilia, hairlike receptors that
extend from cells inside the nose, are
covered with a thin, clear mucus that
dissolves odor molecules not already
in vapor form.
• When the mucus becomes too thick,
it can no longer dissolve the
molecules.
Olfaction
Olfaction
Olfactory Bulb
Mechanoreceptors
Mechanoreceptors
• Respond to being mechanically pushed and pulled
through touch, pressure, gravity, stretch, and movement.
• As their contour changes, mechanoreceptors supply
information to the animal about shape, texture, weight,
and the landscape of objects in the external environment.
• Through the use of mechanoreceptors we can feel,
maintain balance, and even hear.
• Feeling occurs when mechanoreceptors detect touch,
pressure, and pain as objects come in contact with the
skin
• Touch receptors are not distributed evenly over the body.
– The fingertips and tongue may have as many as 100 per cm2; the
back of the hand fewer than 10 per cm2.
Mechanoreceptors
• Other kinds of mechanoreceptors:
– proprioception, or balance, which enables an animal
to know the position of its body and are located within
muscles, tendons, and joints
– Proprioception is our "body sense".
– It enables us to unconsciously monitor the position of
our body.
– It depends on receptors in the muscles, tendons, and
joints.
– If you have ever tried to walk after one of your legs has
"gone to sleep", you will have some appreciation of how
difficult coordinated muscular activity would be without
proprioception.
Brainstem Functions
• http://youtube.com/watch?v=e193uXOq7Z
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• http://youtube.com/watch?v=WavjbJhiRAE
• http://youtube.com/watch?v=FSHGucgnvL
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• http://youtube.com/watch?v=FSHGucgnvL
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