Transcript Pharynx - Biology project

Digestive
System
Pharynx
Our Respiratory system
pharynx
1) nostril,
2) nose,
3) nasal cavity,
4) superior nasal concha,
5) middle nasal concha,
6) inferior nasal concha,
7) nasopharynx,
8) oropharynx,
9) laryngopharynx
10) larynx,
11) trachea,
12) bronchus,
13) lung,
14) thyroid cartilage
Where is the pharynx located ?
The cavity at the back of the mouth.
Is cone-shaped and has an average length of
76mm.
Lined with mucous membrane
Part of the digestive system and repiratory
system of many organisms.
A flap of connective tissue called the
epiglottis closes over the trachea when food
is swallowed to prevent choking or aspiration.
In humans, the pharynx is important in
vocalization.
More about Mucous membrane
The mucous membranes are linings
of mostly, which are involved in
absorption and secretion.
It is found at several places
continuous with skin: at the nostrils,
the lips, the ears, the genital area, and
the anus and the pharynx.
FUNCTION of the pharynx
Facilitate the passage of the food bolus into the
esophagus. Pharynx is designed to direct the food
bolus in this direction.
Second phase of swallowing takes place at the
pharynx. The moistened food bolus is moved to the
back of the mouth by the tongue
An involuntary swallowing reflex is triggered which
prevents food from entering the respiratory tract.
The tongue closes off the mouth, the soft palate
blocks the nose, and the larynx rises such that the
epiglottis closes off the trachea.
Food then moves from the pharynx into the
esophagus.
Thus no digestion and absorption
takes place.
Reason for absence of absorption:
The food haven’t been digested
Reason for absence of digestion:
there is no presence of enzymes
Structure of pharynx
Pharynx
• Starts at the internal nostrils and
extends partway down the neck
• The wall of the pharynx is made
up of skeletal muscles and lined
with a mucous membrane
• 2 functions:
•  a passageway for air and
food, and
•  a resonating chamber
(amplifying sounds)
for speech sounds
• Consist of 3 divisions
Figure 1-4. The nose.
The pharynx  Look carefully... ...
Never mind if you still don't
know……
 Real live organ 
Now I bet
you will
know

The structure of pharynx (I)
Pharynx describes
the part of the throat
that begins from
behind the nose to
the beginning of the
voice box and the
oesophagus.
Divisions IN PHARYNX
Divisions
Nasopharynx-Specifically related
to the respiratory system.
Location: above the soft
palate,
2 nostrils lead into
nasopharynx.
The auditory tubes
open into the
nasopharynx.
connect it with the
middle ears to equalize
the surrounding & body
pressure
Tonsils (adenoids) are
located in the upper wall
of the nasopharynx.
Soft palate
Floor of the nasopharynx
Closes off the upper
respiratory passageways
during swallowing.
Divisions
oropharynx-related to digestive
system
Location:
below the soft palate
and above the upper
edge of the epiglottis.
The epiglottis is the
flap that prevents
food from entering
the larynx during
swallowing.
Divisions
laryngopharynx-common to
respiratory & digestive system.
Location:
below the edge of the
epiglottis
The digestive and
respiratory systems
lead into this part
from above and lead
off from it below.
Structure of pharynx (i)
• The muscles of the
pharynx consists of
three pharyngeal
constrictors:
• superior
• middle
• inferior
• stylopharyngeus and
palatopharyngeus
muscles
Structure of Pharynx (ii)
Front of nasal part of pharynx, as seen with the laryngoscope
Structure of Pharynx (iii)
• Muscles of the
pharynx, viewed
from behind, together
with the associated
vessels and nerves.
(Modified after
Testut.)
•
symptoms
• no symptoms
If pharynx is damaged and
• If symptoms are present,
similar to those of upper
not functioning properly
respiratory infections such
as colds and other viruses.
due to certain diseases,
• cancer :
genetic birth defects or
• slight sore throat that lasts
for over 2 weeks
injuries...
• hoarseness or a change in
your voice so that your voice
• pharyngeal cancer
sounds muffled
• cause is unknown
• trouble with swallowing or
• common among heavy smokers and
feeling of incomplete
people who drink large amounts of
swallowing
alcohol.
• earache or blocked ear
• 7 times more common in men than
• bloody phlegm coughed up
women and generally occurs after
age 50.
• swollen lymph node in the
neck
• Untreated cancer often spreads
throughout the throat area to the
• hard lump in the throat or in
lymph nodes and into the
the neck lymph node.
bloodstream, where the cancer is
carried to other parts of the body. • Large tumor block the
throat, cutting off the air
• If no treatment, it will continue to
supply, possibly causing you
spread and become life-threatening.
to pass out or suffocate.
• Treatment
• Radiation therapy to shrink the malignant tumor.
• Surgery to remove the tumor. Tissue removed from
another part of your body would be used to replace a
part of the pharynx.
• Chemotherapy with or without radiation treatments and
with or without an operation if the tumor is large and
has spread. Side effects or complications from radiation
or chemotherapy happens such as: nausea.Your health
care provider may suggest medicines for nausea and
vomiting. Your provider may prescribe corticosteroid
drugs to help with possible side effects of cancer-fighting
treatments.
• If early stage: these treatments may result in complete
cure.
Do you think we can still
survive without the pharynx ?
Any failure or missing of the pharynx
can cause breathing, swallowing and
voice problems.
Without the pharynx, it WILL cause
choking or aspiration as food when
swallowed may enter the windpipe by
accident. When that happens, the
person will be suffocated.
Aspiration occurs when some kind of
material -particulate (food, foreign body)
or fluid (gastric contents, blood, or saliva)enters from the pharynx into the trachea
With all these RISKS of having these
problems  choking , aspiration , DO
YOU THINK ONE CAN STILL
SURVIVE IN A CONDITION
WITHOUT A VITAL ORGAN????
glossary
•aspiration is the entry of secretions or
foreign material into the trachea and
lungs . The patient may either inhale the
material, or it may be blown into the
lungs during positive pressure
ventilation or CPR.
Koh Shi Hui (06)
Lim Swee Ling (09)
Lim Zihuan (10)
Niew Yan Ling (14)
Tee Hui Yi (17)
3T2
Websites :
http:// www.hopkinsgi.org/multimedia/database/intro_250_swallow.swf
http://www.sghhealth4u.com.sg/Health4U/otolaryngology/the_thr
oat.htm
Let’s have a short
quiz ,shall we ?
The nose chamber is
sealed by the soft
palate/palate so the
food doesn't enter
the nose.
What happens as a
food bolus is pushed
back by the tongue
into the pharynx?
A cough is a sign that
nerves in the pharynx
(upper throat), larynx
(throat), trachea (main
breathing tube) or large
bronchi (breathing tubes in
the lungs) are irritated.
Why do we cough
or simply why does
a cough occur ?
Little bird, tell me
where is
the position of
the pharynx ?
It is located at the
back of the mouth.