Sensory function

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Transcript Sensory function

Also known as deglutition is divided into 3 phases
Three stages of swallowing
The buccal phase
• This phase occurs voluntarily in the mouth
• It involves breaking down of food in the mouth and food is
chewed and mixed with saliva.
• This turns the food into a bolus ,which makes it easier to swallow.
• Occlusal action of lips help in creating an effective seal
preventing the bolus from dribbling out of the oral cavity .
• Finally tongue forces the bolus (food and fluid ) towards the
pharynx ( throat ) .
• Therefore tongue plays an important role in this process .
The pharyngeal phase
• Occurs involuntary .
• Pharynx (throat ) is involved in this stage .
• When food enters the pharynx ( upper throat area ,above
the voice box) ,the soft palate and uvula fold upward
and cover the nasopharynx.
• This cap prevents the bolus from going into the nasal
• The epiglottis is a flexible cartilaginous flaps at the top of
the larynx( voice box,where we breathe) fold down as
the larynx rises.
• As the opening of the larynx is closed ,food or bolus can
pass only in the oesophagus tuibe .
The oesophageal phase
• Occurs involuntary
• Oesophagus ( food pipe ) is the tube that transports food
directly to the stomach. Oesophageal ,normally closed ,opens to
allow bolus to pass when the larynx rises during swallowing .
• Peristalsis of oesophagus ,which helps to push food into the
Nerves of the mouth
◦ The facial nerve, also known as cranial nerve VII
origin – fibres originate the pons ,travel through the
internal acoustic meatus ,and emerge through the
stlomastoid foramen the lateral aspects of the face.
Motor functions include ;
◦ facial expression eg smile.
◦ It also innervates two salivary glands and the lacrimal
gland ( tear gland )
◦ Sensory function ;
◦ Responsible for the sensation of taste in the anterior
two-thirds of your mouth.
Facial nerve or CN VII
◦ Bell’s palsy :paralysis of facial muscles and loss of taste .
◦ Caused by herplex simplex 1 virus.
◦ Corner of mouth sags and lower eyelid droops.
◦ Tears drip continuously and eye cannot be completely closed.
◦ Condition may disappear spontaneously without treatment.
The trigeminal nerve, also known as cranial nerve V,
Fibers originates from the face to pons via the superior orbital
fissure ,the foramen rotundum and foramen ovale .
• Sensory function -is the most important nerve involved in facial
• Motor function - Innervates the muscles of mastication,helps jaw
move up and down .
• Disorder
•Trigeminal neuralgia –inflammation of nerve ,when nerve is cut
,results in sensation on that side of face.
The glassopharyngeal nerve :Cranial
nerve IX
• The glossopharyngeal nerve
• Origin
Emerges from the medulla oblongata ,leave the skull via the jugular
foramen ,and run to throat.
Is a mixed nerve with motor and sensory functions .
Sensory function
Fibers conduct taste in the posterior one-third of the tongue and general
sensory impulse from the tongue and pharyx..
• Motor function
Innervates part of the tongue and pharynx and provide motor fibers to the
parotid salivary glands .
The Vegas nerve or cranial nerve 10
• The Vagus Nerve Or Cranial Nerve 10
• Our body has a nerve called cranial nerve X, also known as the vagus
nerve, which is a very important player in our body. This is because it's a
nerve that innervates the heart, lungs and the digestive tract( oseophagus
). There is one vagal nerve on either side of your body.
• The only cranial nerve that extends beyond the head and neck.
• The vegus nerve is mixed nerve .
• its sensory function is taste .
• Motor function-The vagus nerve is involved in controlling muscles that help
us swallow our food and move it along our digestive tract in a process we
call 'peristalsis.' Peristalsis is basically a series of muscular contractions and
expansions in your gastrointestinal tract that serve to move food down the
GI tract.the
Cranial XI:Accessory
◦ Formed from the cranial root emerging from the medulla
oblongata and spinal root arising from the superior region of the
spinal cord.
◦ The spinal root passes upward ino thecranium via foramen
◦ The accesory nerve leave the cranium nerve via the jugular
nerve foramen.
◦ Primarily a motor nerve
◦ Supplies nerve to the pharynx, larynx,and soft palate .
Tongue disorders
• Tongue disorders commonly occur in people who smoke or
consume excessive alcohol.
• The tongue is a powerful muscle involved in the critical functions
of speaking, chewing and swallowing.
A variety of diseases and disorders can affect the tongue including
infections, injuries, chronic irritation, abnormal tissue growth and
congenital conditions.
• Many tongue disorders are short-lived; others may cause longterm difficulties, requiring ongoing medical management.
• Leukoplakia is a painless grey or white patch on the tongue that
develops in response to chronic irritation.
• These patches can also develop on the inner cheek regions of
the mouth.
• Cigarette or pipe smoking and use of chewing tobacco increase
the risk for development of leukoplakia.
• Irritation caused by poorly fitting dentures or rough spots on the
teeth can also lead to leukoplakia.
• . A variant of this disorder known as hairy leukoplakia commonly
occurs in people with a weakened immune system.
Macroglossia describes abnormal
tongue enlargement. This condition
can cause misalignment of the teeth
and speech difficulties. Macroglossia
often occurs with certain congenital
or inherited conditions, including
Down syndrome, congenital
hypothyroidism and primary
 Macroglossia can also occur due to
tongue swelling or abnormal tissue
growth caused by a variety of
disorders including multiple myeloma,
sarcoidosis, tongue tumors and certain
• Glossitis is inflammation of the tongue, which may
be transient or chronic
• The tongue may swell, and the surface
characteristically appears smooth and red or
abnormally pale.
• Tenderness and burning commonly occur, which
may interfere with speaking, chewing and
swallowing. Taste disturbances often accompany
• Transient episodes of glossitis may occur due to
burning the tongue with hot foods or liquids, oral
herpes, thrush and allergic reactions to mouthwash,
toothpaste or the plastics in dental appliances such
as retainers or dentures.
Tongue cancer
• Tongue cancer is a form of head and
neck cancer.
• Cancers of the forward two-thirds of the
tongue are oral tongue cancers.
• Those at the back of the tongue are
tongue base cancers. Tongue cancers
usually present as a lump or a non
healing ulcer.
• squamous cell carcinoma as the most
common form of the disease.
• Smoking, use of chewing tobacco and
excessive alcohol consumption increase
the risk for the development of tongue