NMWH
07-19-2010, 02:47 PM
قبل الحديث عن فيزيولوجيا التنفس و التبادل الغازي سنقوم بجولة على الطرق التنفسية لتعداد
وظائفها والوقوف على الوظائف المتعلقة بالجهاز التنفسي وأيضاً ما يتعلق بالصوت والكلام...
Functions of the Airways
Nose: i
http://www.mda-sy.com/up//uploads/images/mda-sy-a687a30ae6.jpg (http://www.mda-sy.com/)
A- Respiratory function
The nose is the first of the respiratory passages throughwhich the
inspired air passes. The function of the nose isto begin the process
by which the air is warmed, moistenedand 'filtered'. i
The projecting conchaeincrease thesurface area and cause turbulence, i
spreading inspired airover the whole nasal surface. The large surface
areamaximises warming, humidification and filtering. i
Warming. This is due to the immense vascularity of themucosa. i
This explains the large blood loss when a nosebleed(epistaxis) occurs. i
Filtering and cleaning of air. This occurs as hairs at theanterior nares
trap larger particles. Smaller particles suchas dust and microbes settle
and adhere to the mucus.Mucus protects the underlying epithelium
from irritationand prevents drying. Synchronous beating of the
ciliawafts the mucus towards the throat where it is swallowedor
expectorated. i
Humidification. This occurs as air travels over the moistmucosa and
becomes saturated with water vapour.Irritation of the nasal mucosa
results in sneezing, a reflexaction that forcibly expels an irritant. i
B- Olfactory function
May be discussed later in the "special senses" section inshaa Allah
PHARYNX
http://www.mda-sy.com/up//uploads/images/mda-sy-1e06741653.jpg (http://www.mda-sy.com/)
Passageway for air and food. i
The pharynx is an organinvolved in both the respiratory and the
digestivesystems: i
Air passes through the nasal and oral parts, andfood through the oral
and laryngeal parts. i
Warming and humidifying. i
By the same methods as inthe nose, the air is further warmed and
moistened as itpasses through the pharynx. i
Taste. i
Hearing. i
Protection. i
The lymphatic tissue of the pharyngeal and laryngeal tonsils produces
antibodies in response to antigens, e.g. microbes. The tonsils are larger in
children and tend to atrophy in adults. i
Speech. i
The pharynx functions in speech; by acting as aresonating chamber for
the sound ascending from thelarynx, it helps (together with the sinuses)
ito give thevoice its individual characteristics. i
LARYNX
(http://www.mda-sy.com/)http://www.mda-sy.com/up//uploads/images/mda-sy-5e90855bfd.jpg (http://www.mda-sy.com/)
Production of sound. i
Sound has the properties of pitch, volume and resonance. i
Pitch of the voice depends upon the length and tightness of the cords. i*
At puberty, the male vocal cords begin to grow longer, hence the lower
pitch of the adult male voice. i
Volume of the voice depends upon the force with which the cords *
vibrate. The greater the force of expired air the more the cords vibrate
and the louder the sound emitted. i
Resonance, or tone, is dependent upon the shape of the mouth, the *
position of the tongue and the lips, the facial muscles and the air in the
paranasal sinuses. i
Speech. i
This occurs during expiration when the soundsproduced by the vocal
cords are manipulated by the tongue, cheeks and lips. i
Protection of the lower respiratory tract. i
During swallowing (deglutition) the larynx moves upwards, occluding
the opening into it from the pharynx and the hinged epiglottis closes
over the larynx. This ensures that food passes into the oesophagus and
not into the lower respiratory passages. i
Passageway for air. This is between the pharynx and trachea. i
Humidifying, filtering and warming. These continue as inspired air
travels through the larynx. i
TRACHEA
http://www.mda-sy.com/up//uploads/images/mda-sy-1bd0bf3b10.jpg (http://www.mda-sy.com/)
Support and patency: i
The arrangement of cartilage and elastic tissue prevents kinking and
obstruction of the airway as the head and neck move. The absence of
cartilage posteriorly allows the trachea to dilate and constrict in
response to nerve stimulation, and for indentation as the oesophagus
distends during swallowing. The cartilages prevent collapse of the tube
when the internal pressure is less than intrathoracic pressure, i.e. at the
end of forced expiration. i
Mucociliary escalator: i
This is the synchronous and regular beating of the cilia of the mucous
membrane lining that wafts mucus with adherent particles upwards
towards the larynx where it is swallowed or expectorated. i
Cough reflex. i
Nerve endings in the larynx, trachea andbronchi are sensitive to
irritation that generates nerveimpulses which are conducted by the
vagus nerves tothe respiratory centre in the brain stem. Thereflex motor
response is deep inspiration followed byclosure of the glottis. The
abdominal and respiratorymuscles then contract and suddenly the air is
releasedunder pressure expelling mucus and/or foreign materialfrom the
mouth. i
Warming, humidifying and filtering of air: i
Thesecontinue as in the nose, although air is normally saturatedand at
body temperature when it reaches the trachea. i
BRONCHI & SMALLER AIR PASSAGES
[/URL]http://www.mda-sy.com/up//uploads/images/mda-sy-9971eb839b.jpg (http://www.mda-sy.com/)
[U]Functions of air passages not involved in gaseous exchange
Control of air entry: i
The diameter of the respiratory passages may be altered by contraction
or relaxation of the involuntary muscles in their walls, thus regulating
the volume of air entering the lungs. These changes are controlled by
the autonomic nerve supply: parasympathetic stimulation causes
constriction and sympathetic stimulation causes dilatation. i
The following functions continue as in the upper airways: i
warming and humidifying-
support and patency-
removal of particulate matter-
cough reflex. i-
Functions of respiratory bronchioles and alveoli
External respiration: will be discussed later.. i
Defense against microbes: At this level, ciliated epithelium, goblet cells
and mucus are no longer present. i
Defense relies on protective cells present within the lung tissue. These
include lymphocytes and plasma cells, which produce antibodies in the
presence of antigens, and macrophages and polymorphonuclear
lymphocytes, which are phagocytic. These cells are most active in the
distal air passages where ciliated epithelium has been replaced by
flattened cells. i
Warming and humidifying. These continue as in the upper airways. i
Inhalation of dry or inadequately humidified air over a period of time
causes irritation of the mucosa and facilitates the establishment of
pathogenic microbes. i
وظائفها والوقوف على الوظائف المتعلقة بالجهاز التنفسي وأيضاً ما يتعلق بالصوت والكلام...
Functions of the Airways
Nose: i
http://www.mda-sy.com/up//uploads/images/mda-sy-a687a30ae6.jpg (http://www.mda-sy.com/)
A- Respiratory function
The nose is the first of the respiratory passages throughwhich the
inspired air passes. The function of the nose isto begin the process
by which the air is warmed, moistenedand 'filtered'. i
The projecting conchaeincrease thesurface area and cause turbulence, i
spreading inspired airover the whole nasal surface. The large surface
areamaximises warming, humidification and filtering. i
Warming. This is due to the immense vascularity of themucosa. i
This explains the large blood loss when a nosebleed(epistaxis) occurs. i
Filtering and cleaning of air. This occurs as hairs at theanterior nares
trap larger particles. Smaller particles suchas dust and microbes settle
and adhere to the mucus.Mucus protects the underlying epithelium
from irritationand prevents drying. Synchronous beating of the
ciliawafts the mucus towards the throat where it is swallowedor
expectorated. i
Humidification. This occurs as air travels over the moistmucosa and
becomes saturated with water vapour.Irritation of the nasal mucosa
results in sneezing, a reflexaction that forcibly expels an irritant. i
B- Olfactory function
May be discussed later in the "special senses" section inshaa Allah
PHARYNX
http://www.mda-sy.com/up//uploads/images/mda-sy-1e06741653.jpg (http://www.mda-sy.com/)
Passageway for air and food. i
The pharynx is an organinvolved in both the respiratory and the
digestivesystems: i
Air passes through the nasal and oral parts, andfood through the oral
and laryngeal parts. i
Warming and humidifying. i
By the same methods as inthe nose, the air is further warmed and
moistened as itpasses through the pharynx. i
Taste. i
Hearing. i
Protection. i
The lymphatic tissue of the pharyngeal and laryngeal tonsils produces
antibodies in response to antigens, e.g. microbes. The tonsils are larger in
children and tend to atrophy in adults. i
Speech. i
The pharynx functions in speech; by acting as aresonating chamber for
the sound ascending from thelarynx, it helps (together with the sinuses)
ito give thevoice its individual characteristics. i
LARYNX
(http://www.mda-sy.com/)http://www.mda-sy.com/up//uploads/images/mda-sy-5e90855bfd.jpg (http://www.mda-sy.com/)
Production of sound. i
Sound has the properties of pitch, volume and resonance. i
Pitch of the voice depends upon the length and tightness of the cords. i*
At puberty, the male vocal cords begin to grow longer, hence the lower
pitch of the adult male voice. i
Volume of the voice depends upon the force with which the cords *
vibrate. The greater the force of expired air the more the cords vibrate
and the louder the sound emitted. i
Resonance, or tone, is dependent upon the shape of the mouth, the *
position of the tongue and the lips, the facial muscles and the air in the
paranasal sinuses. i
Speech. i
This occurs during expiration when the soundsproduced by the vocal
cords are manipulated by the tongue, cheeks and lips. i
Protection of the lower respiratory tract. i
During swallowing (deglutition) the larynx moves upwards, occluding
the opening into it from the pharynx and the hinged epiglottis closes
over the larynx. This ensures that food passes into the oesophagus and
not into the lower respiratory passages. i
Passageway for air. This is between the pharynx and trachea. i
Humidifying, filtering and warming. These continue as inspired air
travels through the larynx. i
TRACHEA
http://www.mda-sy.com/up//uploads/images/mda-sy-1bd0bf3b10.jpg (http://www.mda-sy.com/)
Support and patency: i
The arrangement of cartilage and elastic tissue prevents kinking and
obstruction of the airway as the head and neck move. The absence of
cartilage posteriorly allows the trachea to dilate and constrict in
response to nerve stimulation, and for indentation as the oesophagus
distends during swallowing. The cartilages prevent collapse of the tube
when the internal pressure is less than intrathoracic pressure, i.e. at the
end of forced expiration. i
Mucociliary escalator: i
This is the synchronous and regular beating of the cilia of the mucous
membrane lining that wafts mucus with adherent particles upwards
towards the larynx where it is swallowed or expectorated. i
Cough reflex. i
Nerve endings in the larynx, trachea andbronchi are sensitive to
irritation that generates nerveimpulses which are conducted by the
vagus nerves tothe respiratory centre in the brain stem. Thereflex motor
response is deep inspiration followed byclosure of the glottis. The
abdominal and respiratorymuscles then contract and suddenly the air is
releasedunder pressure expelling mucus and/or foreign materialfrom the
mouth. i
Warming, humidifying and filtering of air: i
Thesecontinue as in the nose, although air is normally saturatedand at
body temperature when it reaches the trachea. i
BRONCHI & SMALLER AIR PASSAGES
[/URL]http://www.mda-sy.com/up//uploads/images/mda-sy-9971eb839b.jpg (http://www.mda-sy.com/)
[U]Functions of air passages not involved in gaseous exchange
Control of air entry: i
The diameter of the respiratory passages may be altered by contraction
or relaxation of the involuntary muscles in their walls, thus regulating
the volume of air entering the lungs. These changes are controlled by
the autonomic nerve supply: parasympathetic stimulation causes
constriction and sympathetic stimulation causes dilatation. i
The following functions continue as in the upper airways: i
warming and humidifying-
support and patency-
removal of particulate matter-
cough reflex. i-
Functions of respiratory bronchioles and alveoli
External respiration: will be discussed later.. i
Defense against microbes: At this level, ciliated epithelium, goblet cells
and mucus are no longer present. i
Defense relies on protective cells present within the lung tissue. These
include lymphocytes and plasma cells, which produce antibodies in the
presence of antigens, and macrophages and polymorphonuclear
lymphocytes, which are phagocytic. These cells are most active in the
distal air passages where ciliated epithelium has been replaced by
flattened cells. i
Warming and humidifying. These continue as in the upper airways. i
Inhalation of dry or inadequately humidified air over a period of time
causes irritation of the mucosa and facilitates the establishment of
pathogenic microbes. i