RESPIRATORY ORGANS
It includes: 
Nose. 
Pharynx. 
Larynx. 
Trachea. 
Bronchi and 
bronchioles.
Lungs and 
alveoli.
NOSE
It opens externally 
on the face by the
nostrils (external
nares).
The nasal cavity is 
divided by the
midline nasal
septum.
It is separated from 
the oral cavity by the
palate.
LINING MUCOSA
The olfactory 
mucosa is in the
superior part of the
nasal cavity.
The rest of the 
mucosa is
respiratory.
LINING MUCOSA
The nasal mucosa 
has a a rich
network of veins
to:
1. warms the air. 
2. The sticky 
mucous secretion
moistens the air.
3. Traps bacteria 
and foreign bodies.
NASAL CAVITY
The ciliated cells
of the nasal
mucosa move
the mucous
backwards to the
throat where it is
swallowed.

CONCHAE
They are three 
mucous-covered
projections in the
lateral wall of the
nasal cavity.
They increase the 
surface area of the
mucosa exposed to
the air.
PHARYNX (THROAT)
It is a muscular tube. 
It is a common pathway
for food and air.
It is continuous with the
nasal cavity through the
internal nares.
It terminates in the 
esophagus.


PHARYNX
It passes behind. 
(1) The nasal cavity
(Nasopharynx).
(2) Oral cavity 
(Oropharynx). 
(3) Larynx 
(Laryngopharynx 

PHARYNX
It has clusters of 
lymphoid tissue.
The pharyngeal tonsil
(Adenoid): in the
nasopharynx.
Palatine tonsil :in the
oropharynx.
Lingual tonsil : at the
base of the tongue.



NASOPHARYNX
It is continuous 
with the nasal
cavity through the
internal nares.
It receives the 
openings of the
pharyngotympanic
tubes to connect
with the middle
ear.
LARYNX
Functions : 
1. It directs food and 
air into their proper
channels.
2. It has a role in 
speech.
It is formed of (8) 
hyaline cartilages
The Thyroid cartilage is
the largest.

LARYNX
Thyroid cartilage: is the
largest.
Epiglottis: 
Is a single flap of elastic
cartilage


VOCAL (TRUE VOCAL) FOLDS
They are made of
the mucous
membrane of the
larynx.
They vibrate with
the expelled air
and produce
sounds.
The passage 
between them is
the glottis.


TRACHEA
It begins from 
the larynx.
It ends at the 
level of T (5).
It is (10-12) cm. 
Its walls are 
reinforced with C
shaped hyaline
cartilages.
TRACHEA
The open parts of the 
rings allow the
oesophagus to
expand anteriorly
during swallowing.
The rigid parts keep 
the trachea patent.
MAIN BRONCHI
Right main bronchus: 
Wider. 
Shorter. 
Straighter. 
(than the left) 
It is the more common
site to lodge foreign
bodies.

I
LUNGS
They are paired 
organs.
They lie in the 
thoracic cavity on
each side of the
mediastinum.
LUNGS
Each lung has : 
Apex : 
It is narrow and located 
deep to the clavicle.
Base : 
Broad and rests on the 
diaphragm.
Fissures : 
Two in the right lung 
and one in the left.
LUNGS
Lobes : 
The right lung has 
three lobes
(upper,middle and
lower).
The left lung has two
lobes (upper and
lower).

PLEURA
Visceral : 
A serous 
membrane
covering the
lung.
Parietal : 
It lines the 
thoracic walls.
RESPIRATORY TREE
1. primary (main) 
bronchi.
2. Secondary. 
3. Tertiary. 
4. Terminal 
Bronchioles.
5. Respiratory 
bronchioles.
6. Alveolar ducts. 
7. Alveolar sacs. 
RESPIRATORY ZONE
It is the only site for gas 
exchange in the lungs.
It consists of: 
1. Respiratory 
bronchioles.
2. Alveolar ducts. 
3. Alveolar sacs. 
4. Alveoli. 
Millions of alveoli make 
up the bulk of the lung
which are mostly air
spaces.
CONDUCTING ZONE
It conduits air to and 
from the respiratory
zone.
It consists of : 
1. Nose. 
2. Pharynx. 
3. Larynx. 
4. Trachea. 
5. Bronchi. 
6.Terminal bronchioles.
