The respiratory system
1. - Functional anatomy
2. - The upper respiratory system
3. - The lower respiratory system
4. - The lungs and pleurae
SASBOU Tarik , MD , DESAIC
Academic year 2022-2023
UM6P
• The laryngeal prominence (Adam's apple) is the central prominence
on the __________.
– thyroid cartilage
– cricoid cartilage
– hyoid bone
• The bronchi enter the lungs at the area called the __________.
– apex
– base
– Hilum
• Transporting oxygen gas throughout the body is considered to be
__________ respiration.
– external
– internal
– pulmonary
Mini Quiz
Skeleton of Thoracic wall
Thoracic vertebrae
scapula
Superior aperture of the thorax
1st ribs
diaphragm
Inferior aperture of thorax
Posterior view of thorax skeleton
Anterior view of the bony thorax
Lungs and Mediastinum
Pulmonary cavity
Mediastinum
❶
Gases
And
Ventilation
The respiratory system is responsible for :
❷
❸
the respiratory and circulatory systems are closely coupled
The MAJOR function is : cellular respiration
Bloodstream
And
Circulation
❹
Processes of
Respiration
Thorax « VENTILATION »
-- Breathing mecanism -Inspiration
❶
In pulmonary
ventilation, air
is inhaled
through the
expiration nasal and oral
cavities . It
moves through
the pharynx,
larynx, and
trachea into
the lungs. Then
exhaled,
flowing back
through the
same pathway.
Functional ANATOMY
The upper respiratory system warms,
humidifies, and filters air
from the nose to the larynx
consists of the larynx
and all the structures
below it.
The lower respiratory system consists of
conducting and respiratory zone structures
Quiz - Overview of the Respiratory System
Upper Respiratoiry System
Rhinitis :
inflammation
Nasal cavity
Sinusitis
Bronchitis
Pneumonia
warm and humidify inhaled air
Voice production
Filter and protection
The Nose and Paranasal Sinuses
• The structures of the nose are divided into the extenal nose and the
internal nasal cavity
• Noses vary in size and shape, largely because of differences in nasal
cartilages
• The conchae and nasal mucosa function during inhalation to filter, heat,
and moisten incoming air
• The nasal cavity is surrounded by a ring of paranasal sinuses
• The paranasal sinuses are four paired, air-filled cavities found inside bones
of the skull.
• These sinuses are named for the skull bones that contain them: -Frontal Ethmoidal - Sphenoidal – Maxillary
• Mucosae line the paranasal sinuses and help to warm and humidify the air
we inhale.
• When air enters the sinuses from the nasal cavities, mucus formed by the
muscosae drains into the nasal cavities.
• Nasal cilia moves mucus toward throat to be swallowed and digested
Nasal cavity « olfaction »
Chemicals in the air
Nervous system receptors
on the cilia
( openings in the ethmoid bone )
olfactory fibers
(signal sent to the brain)
olfactory bulbs
cranial nerve 1
Olfactory area of
the cerebral cortex
The Nose and Paranasal Sinuses
The nose is :
- An Airway
- Warms air
- A Filter
- A Resonating
chamber of
Speech
- A House of
olfactory Recep
External
nose
nasal mucosa
is richly
supplied with
sensory nerve
endings
.
Internal
nasal cavity
The Pharynx « throat »
// Mid sagittal section of the head and neck //
the BASE of the skull
13cm
NC
the 6th cervical vertebra
L
Infected and swollen adenoids
block air passage in the
nasopharynx ;When the adenoids
are chronically enlarged,
both speech and sleep may be
disturbed !!!
The pharynx, larynx, and upper trachea.
Upper Respiratory Tract
Or nostrils
The Upper Respiratory System +++
to summarize :
Larynx
from the level of the third cervical vertebrae C3 ‘guardian of the airways’
the laryngopharynx
5cm
the trachea.
to the sixth cervical vertebrae C6
-The larynx has 3 functions:
1• Provide a patent (open) airway
2• Act as a switching mechanism to route air and food into the proper channels « epiglottis »
3• Voice production [because it houses the vocal folds (vocal cords)]
Larynx
*2 types of Epithelium lining the Larynx :
 Stratified squamous epithelium and pseudostratified ciliated columnar  filter function
*Voice Production : length of VC , size of glottis , rythm of VC vibration , force of
airstream
*Sphincter functions during abdominal strain that prevent air passage
The voice box
*Phonation is  the
creation of sound by
structures in the upper
respiratory tract of the
respiratory system.
-During exhalation, air
passes from the lungs
through the larynx, or
“voice box.”
- When we speak,
muscles in the larynx
move the arytenoid
cartilages. This action
pushes the VC , or vocal
folds, together, air
passing between them
makes them vibrate,
creating sound
Vocal cords
- Inflammation of the vocal folds, or laryngitis, causes swelling , interfering with their
vibration.
 This changes the vocal tone ,causing hoarseness .
- Laryngitis is often caused by viral infections, but also by overusing the voice,
, very dry air, bacterial infections, tumors on the vocal folds, or inhalation of irritating
chemicals
The Trachea « windpipe »
The trachea or windpipe, long vertical tube ,
descends from the larynx through the neck
and into the mediastinum
It ends by dividing into the two main bronchi
at mid thorax ( sternal angle )
R
In humans, it is 10-12 cm (about 4 inches) long
and 2 cm (3/4 inch) in diameter
very flexible and mobile.
Cila + mucus are involved in protecting the lungs
Mucociliary escalator
The Tracheal wall composition
Several layers
(Expansion )
(Contraction )
Cilia under electron microscope
C- shape cartilage of trachea  patent air way + esophagus can expand anteriorly as swallowed
food passes through it.
smoking inhibits and ultimately destroys cilia. Without ciliary activity, coughing is the only way
to prevent mucus from accumulating in the lungs. When someone stops smoking, ciliary
function usually recovers within a few weeks, and the morning "smoker's cough" subsides.
The Bronchi and Subdivisions
At the tips of the bronchial tree, conducting zones ,
wich give way to respiratory zone structures
 as the conducting tubes become smaller,
structural changes occur !!
≠The Right main bronchus
is wider, shorter, and more
vertical than the Left.≠
Respiratory Zone :Defined by the
presence of thin-walled air sacs called alveoli
Bronchial tree
T7
Conducting tubes : trachea +main bronchi +lobar bronchi 3/2 + segmental bronchi + T bronchioles
The Respiratory Membrane
Elastic fibers and capillaries surround all alveoli !!
Type II alveolar cells secrete surfactant
Respiratory Membrane : thin layer of alveolar cells + basement membrane + cap endothelium
 Blood- air barrier : gas exchanges by simple diffusion
++++++
Lungs
• The tip of each lung is called apex , wich extends
superiorly to the first rib .
• The base of each lung is concave  diaphragmatic
surface
• Lateral and postero-anterior rounded surface  costal
surface
• Medial part is also concave arround the heart  the
mediastinal surface
• Root or Hilum of each lung is located in the medial
surface of each lung ( PA sup to PV , ant to AW , N , L )
• 3 lobes on the right , 2 lobes on the left separated by
fissures .
• 10 Bronchopulmonary segments by lung
Lungs
Each multilobed lung occupies its own pleural cavity , they form the major part of thoracic
cavity , subdivised into lobes by fissures . lung tissue is mostly elastic connective tissue.
≠The left lung is
smaller than the right ≠
Anatomical relationships of organs in the thoracic cavity.
In (c), the size of the pleural cavity is exaggerated for clarity.
Bronchial Tree
and Blood suply
Anatomical relationships of organs in the
thoracic cavity. In (c), the size of the
pleural cavity is exaggerated for clarity.
The bronchial
arteries
arise from the aorta !!
Blood Supply and
Innervation of the Lungs
• The lungs are perfused by two circulations : the pulmonary and the
bronchial
 Pulmonary Circulation of the Lungs ;
– the pulmonary arteries branch profusely along with the bronchi
and finally feed into the pulmonary capillary networks
surrounding the alveoli , they carry deoxygenated blood .
– The pulmonary veins convey the freshly oxygenated blood from
the respiratory zone of the lungs to the heart
• The pulmonary circuit is a low-pressure, high-volume circulation
• the bronchial arteries provide oxygenated systemic blood to lung
tissue  bronchial circulation of the lungs
• The bronchial veins drain systemic venous blood from the lungs, but
there are multiple anastomoses between the two circulations, and
most venous blood returns to the heart via the pulmonary veins.
• The lungs are innervated by parasympathetic and sympathetic
motor fibers, and visceral sensory fibers ( constriction / dilation )
The pleurae ( sides )
• It forms a thin,
double-layered
serosa
– parietal pleura
covers the thoracic
wall
– visceral pleura covers
the external lung
surface
• pleurae produce
pleural fluid , wich
fills pleural cavity
Some pleural( sides ) disorders
• pleuritis : inflammation of the pleurae, often results
from pneumonia.
• As the disease progresses, the pleurae may produce
excessive amounts of fluid.
• This increased fluid relieves the pain caused by pleural
surfaces rubbing together, but may exert pressure on
the lungs and hinder breathing movements.
• the term for fluid accumulation in the pleural cavity is
pleural effusion.
Hypoxia
• Inadequate oxygen delivery to body tissues is called
hypoxia
• Fall of Hb saturation
• The mucosae and nail beds are often the easiest places
to observe this color changecyanosis
• Hypoxia is classified based on cause :
– Anemic hypoxia
– Ischemic hypoxia
– Histotoxic hypoxia
– Hypoxemic hypoxia
– Carbon monoxide poisoning