Respiratory system Anatomy

‫الرحي‬ ‫الرحمن‬ ‫هللا‬ ‫بسم‬‫م‬

DARWISH BADRAN
‫للخطوط‬ ‫هو‬ ‫العرض‬ ‫هذا‬
‫وي‬ ‫المادة‬ ‫لدراسة‬ ‫الرئيسة‬‫بقى‬
‫فقط‬ ‫الكتاب‬ ‫لها‬ ‫المرجع‬.

Darwish H. Badran MD, PHD, FFDRCSI
Professor of Anatomical Sciences
Anatomy of the Respiratory System

The Nose & Nasal Cavity
DARWISH BADRAN

Columella
Philtrum
DARWISH BADRAN

Nasal Cavity
Basic Structure
The Nares (nostrils):open into the nasal cavity at the vestibule.
The Choana: opens into the nasopharynx.
The Septum: extends medially from the roof to the floor.
Cartilage + bone.
Conchae (turbinates): Project from the lateral wall into the
cavity.
Meatus: a slit like space below the conchae.
DARWISH BADRAN

Floor of the Nasal Cavity
The hard palate,
formed by:
• The palatine process of the
maxilla and horizontal
plate of palatine bone.
• Has the incisive foramen
which transmits:
• Nasopalatine nerve.
• Sphenopalatine artery.
DARWISH BADRAN

Roof of the Nasal Cavity
Anterior (sloping):
• Frontal and nasal bones
Middle (horizontal):
• Cribriform plate of the
ethmoid.
Posterior (sloping):
• Body of he sphenoid
DARWISH BADRAN

Medial Wall of the Nasal Cavity
The nasal septum forms
the medial wall.
It is commonly deviated
to one side.
Parts:
• Anteriorly: Septal cartilage.
• Postero-inferior: Vomer bone.
• Postero-superior:
Perpendicular plate of the
ethmoid.
DARWISH BADRAN

Lateral Wall of the Nasal Cavity
The maxilla, antero-
inferiorly
The perpendicular plate
of the palatine bone
posteriorly.
The three concha and
meatuses below them.
Sphenoethmoidal recess
above the superior
concha.
DARWISH BADRAN

Nasal Mucosa….(1)
Olfactory:
• Covers the
superior nasal
concha and the
upper 1/3 of the
nasal septum.
• It appears
yellowish in color.
DARWISH BADRAN

Nasal Mucosa….(2)
Conductive:
• Covers the lower part of the nasal
cavity.
• Appears purple in color.
• Covered by skin in its lower part 
vestibule.
• Covered by respiratory epithelium in its
upper part.
• The junction between the 2 epithelia
_white line (mucocutaneous junction).
DARWISH BADRAN

Venous Drainage of the Nasal Cavity
Nasal veins tend to drain into the
pterygoid plexus.
The submucous plexus modifies the
physical properties of air.
Venous engorgement is associated with
mucosal edema occlusion of the airway.
DARWISH BADRAN

Innervation of the Nasal Cavity
Antero-superior quadrant:
• Anterior ethmoidal nerve (nasociliary).
Antero-inferior quadrant:
• Anterior superior alveolar nerve (maxillary).
Postero-superior quadrant:
• Sphenopalatine nerve and nasal branches of the sphenopalatine
ganglion.
Postero-inferior quadrant:
• Greater palatine nerve.
DARWISH BADRAN

Innervation of the Nasal Septum
Olfactory nerve.
Anterior ethmoidal nerve.
Sphenopalatine nerve.
Posterior superior alveolar nerve.
DARWISH BADRAN

Epistaxis and Little’s Area
Epistaxis: bleeding from the nose.
Commonly occurs from Little’s area:
• Lies in the anterior part of the nasal septum, 2.5 cm from the nares,
opposite the vestibule.
• It is the site of anastomosis of:
• Sphenopalatine artery.
• Greater palatine artery.
• Septal branches of the facial.
Arteries in the area form together Kieselbach’s plexus.
DARWISH BADRAN

Blood Supply of the Nasal Cavity
anterosuperior quadrant
Anterior and posterior
ethmoidal
posterosuperior
quadrant
Sphenopalatine artery
anteroinferior quadrant
& nasal septum
Superior labial of facial
Posteroinferior quadrant
Greater palatine artery
Supplied in quadrants
DARWISH BADRAN

Vessels and Nerves of the Nasal Septum
DARWISH BADRAN

Paranasal
Sinuses
DARWISH BADRAN

At birth, all sinuses
are rudimentary
EXCEPT the
frontal sinus (by 2nd
year).
DARWISH BADRAN

Functions of the paranasal sinuses
Sinuses lighten the facial skeleton?!!.
Sinuses produce resonance of the voice.
They may act as insulators.
DARWISH BADRAN

All sinuses are lined with
respiratory epithelium.
Gravity plays no role in
emptying a normal sinus.
DARWISH BADRAN

Sinuses undergo two
phases of rapid
enlargement; one at
6-7 years and another
phase after puberty.
DARWISH BADRAN

Maxillary Sinus
The largest sinus, occupies the body of the
maxilla its average volume is ~15ml.
Pyramidal in shape with the base directed
towards the nose.
The ostium lies in the upper part of the base
of the sinus.
It drains into the hiatus semilunaris of the
middle meatus.
DARWISH BADRAN

Relations of the Maxillary Sinus
Superiorly: the floor of the orbit.
Inferiorly: 2nd premolar and 1st molar teeth.
Anteriorly: the cheek.
Posteriorly: pterygopalatine fossa.
Medially: nasal cavity.
DARWISH BADRAN

Innervation of the Maxillary Sinus
Anterior superior alveolar nerve: supplies the pulp of the canine and
incisors, and the antero-inferior quadrant of the lateral nasal wall.
Middle superior alveolar nerve: supplies the premolar teeth and the
overlying antral mucosa.
Posterior superior alveolar nerve: supplies the molars and gives tiny
branches to the mucosa.
Greater palatine nerve: minute branches to supply the posterior part of
the medial wall of the sinus.
Infra-orbital nerve: supplies the roof of the antrum.
Remember: the infraorbital nerve is related to the roof of the sinus.
DARWISH BADRAN

Relation of the Teeth to the Maxillary
Sinus
Maxillary canine raises a ridge on the facial surface of the
wall of the maxilla but not on the wall of the sinus.
The posterior 5 teeth lie below the floor of the sinus.
The roots of the 1st molar and the 2nd premolar lie nearest
to the to the curve of the base of the sinus.
Improper extraction or implantation may lead to antro-oral
fistula particularly in old age.
Maxillary teeth and the mucosa of the maxillary sinus are
innervated by the superior alveolar nerve.
DARWISH BADRAN

The sinus is lined with mucoperiosteum, with cilia that beat
toward the ostia.
This membrane is also referred to as the "Schneiderian
Membrane", which is histologically a bilaminar membrane
with ciliated columnar epithelial cells on the internal (or
cavernous) side and periosteum on the osseous side.
a genuine osteogenic potential is associated with the
membrane and can contribute to development of successful
sinus augmentation techniques
Schneiderian Membrane
DARWISH BADRAN

Other
Paranasal Sinuses
DARWISH BADRAN

Frontal Air Sinuses
The right and left sinuses are unequal and separated
by a septum which is commonly resorbed in old age.
The ostium is present at the lower medial corner.
Drains into the middle meatus.
Innervated by the supraorbital and supratrochlear
nerves.
DARWISH BADRAN

Ethmoidal Air Cells
Arranged in groups (anterior, middle and posterior).
Each sinus contains 3-20 air cells, separated by a thin
incomplete bony septa.
Innervated by anterior and posterior ethmoidal nerves
and branches from the pterygopalatine ganglion.
DARWISH BADRAN

The Ethmoidal Air Cells
The anterior drain into the middle meatus
in the hiatus semilunaris.
The middle drain on or above the bulla
ethmoidale.
The posterior drain into the superior
meatus.
DARWISH BADRAN

Sphenoid Air Sinus
Present in the body of the sphenoid.
Innervated by the posterior ethmoidal nerve and the
orbital branch of the sphenopalatine ganglion.
Relations: ?????
It drains into the spheno-ethmoidal recess.
DARWISH BADRAN

The nasolacrimal
duct drains into
the inferior meatus.
DARWISH BADRAN

Nasal Meatuses
Sphenoethmoidal recess  Sphenoid sinus.
Superior meatus Posterior ethmoidal sinus.
Middle meatus _ Frontal, maxillary, anterior and
middle ethmoidal sinuses.
Inferior meatus _ Nasolacrimal duct.
DARWISH BADRAN

It is a musculo-fascial tube
incomplete anteriorly.
Extends from the base of the
skull to the level of C6; it
continues as the esophagus.
Runs in front of the vertebral
column and behind the nose,
mouth and larynx
Its diameter decreases from
3.5 cm to 1.5 cm.
DARWISH BADRAN

Lies behind the nose and soft palate.
Its posteromedial wall is formed by
the anterior arch of the atlas and
sphenoid bone.
It is an airway only.
Contains:
• Naopharyngeal tonsil
• Opening of Eustachian tube.
• Tubal tonsil
• Salpingopharyngeal fold
• Pharyngeal recess
Nasopharynx
DARWISH BADRAN

Lies behind mouth.
Extends between the soft
palate and the upper of the
epiglottis
Lies in front of the bodies of
C2 & C3
Contains:
• Palatine tonsil
Oropharynx
DARWISH BADRAN

Lies in front of the
bodies of C3 – C6.
Extends from the
epiglottis to the lower
border of C6.
Contains:
• Piriform fossa on each side
Laryngopharynx
DARWISH BADRAN

Superior constrictor:
• Origin: medial
pterygoid plate and
hamulus, and the
pterygomandibular
raphe
• Insertion: pharyngeal
raphe
Muscles of the Pharynx
DARWISH BADRAN

Middle constrictor:
• Origin: grater and
lesser horns of the
hyoid bone, and the
stylohyoid ligament
• Insertion: pharyngeal
raphe
DARWISH BADRAN

Inferior constrictor:
• Parts:
• Thyropharyngeus: from
the side of the laryngeal
cartilage to the pharyngeal
raphe.
• Cricopharyngeus: from
the arch of the cricoid
cartilage; muscles from
both sides merge together.
DARWISH BADRAN

Stylopharyngeus: from the
styloid procaess to the thyroid
cartilage.
Palatopharyngeus: from
palatal aponeurosis to the
pharynx.
Salpingopharyngeus: the
cartilaginous part of Eustachean
tube to the posterior border of
thyroid lamina.
DARWISH BADRAN

Homework:
DARWISH BADRAN
What (is) are the gap(s) in the lateral pharyngeal wall?
What (is) are the structure(s) passing through each of them?
Name the arteries supplying the pharynx.
What are the components of the pharyngeal plexus?

An airway extending
from the root of the
tongue to the lower
border of cricoid
cartilage.
Formed of cartilages and
ligaments.
Lined by a mucous
membrane.
DARWISH BADRAN

Single:
• Thyroid
• Cricoid
• epiglottis
Paired:
• Arytenoid
• Cuniform
• Corniculate
Cartilages:
DARWISH BADRAN

Name the intrinsic laryngeal
muscles.
Mention the function(s) of
each of them.
Name the nerve supply of
each of them.
Name the abductor(s) and
adductor(s) of the vocal cord.
Laryngeal muscles
DARWISH BADRAN

DARWISH BADRAN
The vestibular folds are covered by
respiratory epithelium.
The vocal cords are covered by
stratified squamous non-keratinized
epithelium.

Trachea: Landmarks
Begins at lower border of cricoid
cartilage / C6
Extends to Carina
• Right of the midline
• Sternal angle
• T4 on inspiration / T6 on expiration
15 cm long / 2cm in diameter
15 – 20 incomplete rings of cartilage
• Bridged posteriorly by trachealis muscle
DARWISH BADRAN

Trachea
Variable shape
• Usually round, oval, oval with
flattened posterior border
• Square
• Inverted pear
• Horseshoe
Very pliable in
children
DARWISH BADRAN

Trachea: Carina
Lies at T5 level
• T4 on expiration
• T6 on inspiration
Normal angle: 55°-65°
• 20° to right of midline
• 40° to left of midline
Angle slightly larger and
symmetrical in children
Angle increases by 10° - 15°
in recumbency
DARWISH BADRAN

Relations: Cervical
Anterior:
• Isthmus anterior to 2nd, 3rd, 4th
rings
• Inferior thyroid veins
• Strap muscles: Sternohyoid,
Sternothyroid
Posterior:
• Oesophagus, recurrent laryngeal
nerves
Lateral:
• Lobes of thyroid
• Common carotid artery
DARWISH BADRAN

Relations: Thoracic
Anterior:
• Brachiocephalic a.
• Left common carotid a.
• Left brachiocephalic v.
DARWISH BADRAN

Relations: Thoracic
Posterior:
• Oesophagus
• Left recurrent laryngeal n.
DARWISH BADRAN

Relations: Thoracic
Left lateral:
• Arch of the aorta
• Left common carotid a.
• Left subclavian a.
Right lateral:
• Right vagus nerve
• Arch of the azygos vein
• Pleura
DARWISH BADRAN

Blood supply
Upper part
• Inferior thyroid artery
Lower part
• Branches of the bronchial
artery
Venous drainage
• Inferior thyroid venous
plexus
DARWISH BADRAN

Surface Anatomy of the Pleura
2
6
4
6
8
DARWISH BADRAN

Apex (of each lung): lies one inch
above the medial 1/3 of the clavicle.
Right pleura:
• The anterior margin extends vertically from
sternoclavicular joint to 6th costal cartilage.
• Inferior margin : passes round chest wall, on
the 8th rib in midclavicular line, 10th rib in mid-
axillary line and finally reaching to the last
thoracic spine.
• Posterior margin : along the vertebral column
from the apex to the inferior margin.
Left pleura:
• The anterior margin extends from
sternoclavicular joint to the level of 4th costal
cartilage, then deviates for about 1 inch to left
at 6th costal cartilage to form cardiac notch.
Surface Anatomy of the Pleura
DARWISH BADRAN

Apex, anterior border and posterior
border correspond nearly to the lines of
pleura but are slightly away from the median
plane.
Inferior margin:
• as the pleura but more horizontal and
finally reaching to the 10th thoracic spine.
Oblique fissure:
• represented by a line extending from 3rd
thoracic spine, obliquely ending at 6th
costal cartilage.
Transverse fissure only in right lung:
represented by a line extending from 4th right
costal cartilage to meet the oblique fissure.
Surface Anatomy of the Lungs
DARWISH BADRAN

It is a closed serous sac which
surrounds the lung and invaginated
from its medial side by the root of
lung.
It has 2 – layers:
• parietal pleura which lines the thoracic cavity.
• visceral pleura which surrounds the lung,
separated by a pleural cavity.
Pleural cavity:
• Contains 5-10 ml. of serous fluid which
lubricates both surfaces and allows the lungs to
move free during respiration.
The Pleura
DARWISH BADRAN

1- Cervical pleura:
It is part of parietal pleura which protrudes up
into the root of the neck.
2-Costal pleura:
It lines inner surface of ribs, costal cartilages,
intercostal muscles and back of the sternum.
Innervated by intercostal nerves.
3-Diaphragmatic pleura:
It covers upper surface of the diaphragm.
Innervated medially by the phrenic nerve, and
peripherally by the lower 6 intercostal nerves.
4-Mediastinal pleura: It covers mediastinal
surface of the lung. Innervated by the phrenic
nerve.
Parts of Parietal
Pleura
DARWISH BADRAN

Firmly covers outer surfaces of the lung and
extends into its fissures.
The 2- layers (mediastinal parietal pleura &
visceral pleura) are continuous with each other to
form a tubular sheath (pleural cuff) that
surrounding root of lung (vessels, nerves &
bronchi) in the hilum of the lung.
On the lower surface of root of the lung, pleural
cuff hangs down as a fold called pulmonary
ligament.
Innervated by sympathetic fibres from
pulmonary plexus.
Visceral Pleura
DARWISH BADRAN

Anterior border : is sharp, thin and
overlaps the heart.
Anterior border of left lung
presents a cardiac notch at its
lower end + thin projection called
the lingula below the cardiac notch.
Posterior border : is rounded, thick
and lies beside the vertebral
column
Lungs .. General ..1/3
DARWISH BADRAN

The lung is conical in shape.
• It has an apex, a base and 2 surfaces.
• The costal surface of each lung borders the ribs
(front and back).
• On the medial (mediastinal) surface, the bronchi,
blood vessels, and lymphatic vessels enter the lung
at the hilum.
Apex: projects into root of the neck
(one inch above the medial 1/3 of the
clavicle) and it is covered by cervical
pleura.
Base: (inferior= diaphragmatic
surface) is concave and rests on the
diaphragm.
DARWISH BADRAN

Costal surface:
• Convex.
• Covered by costal pleura which
separates lung from: ribs, costal
cartilages & intercostal muscles.
Medial surface: It is divided
into 2 parts:
• Anterior (mediastinal) part:
• Contains a hilum in the middle (it is
a depression in which bronchi,
vessels, & nerves forming the root
of lung).
• Posterior (vertebral) part:
• It is related to: bodies of thoracic
vertebrae, intervertebral discs,
posterior intercostal vessels &
sympathetic trunk.
DARWISH BADRAN

Larger & shorter than
left lung.
Divided by 2 fissures
(oblique & horizontal)
into 3 lobes (upper,
middle and lower lobes).
Right Lung
DARWISH BADRAN

Azygos vein and its arch (posterior and
over the root of the lung).
Vagus nerve posterior to the root.
Esophagus above and posterior to the
root.
Phrenic nerve anterior to the root.
Cardiac impression: related to right
atrium.
Below hilum and in front of
pulmonary ligament: Groove for
I.V.C.
Mediastinal Surface of the Right Lung
DARWISH BADRAN

2 bronchi lie posterior.
Pulmonary artery is
superior
2 Pulmonary veins are
inferior and anterior.
Root of the Right Lung
DARWISH BADRAN

Divided by one oblique
fissure into -2 lobes,
Upper and lower.
There is No horizontal
fissure.
It has a cardiac notch at
lower part of its
anterior border.
Left Lung
DARWISH BADRAN

Descending aorta posterior to the root.
Arch of the aorta above the root.
Vagus nerve posterior to the root.
Groove for left common carotid artery.
Groove for left subclavian artery.
Phrenic nerve anterior to the root.
Cardiac impression : related to left
ventricle.
Mediastinal Surface of
the Left Lung
DARWISH BADRAN

One bronchus lies
posterior
Pulmonary artery is
superior
2 Pulmonary veins are
inferior and anterior.
Root of the Left Lung
DARWISH BADRAN

Bronchial arteries (branches of
descending thoracic aorta)….. supply
oxygenated blood to bronchi , lung
tissue & visceral pleura.
Bronchial veins: drain into azygos &
hemiazygos veins.
Pulmonary artery carries
non-oxygenated blood from right
ventricle to the lung alveoli.
2 pulmonary veins from each lung :
carry oxygenated blood to the left
atrium.
Blood Supply of the
Lungs
DARWISH BADRAN

Pulmonary plexus :at
the root of lung. It s
formed of sympathetic
& parasympathetic
fibres.
• 1- Sympathetic: from
sympathetic trunk they are
broncho-dilators and
vasoconstrictors.
• 2- Parasympathetic: from
the Vagus nerve. They are
broncho-constrictors and
secretomotor to bronchial
glands and vasodilators.
Nerve Supply of the
Lung
DARWISH BADRAN

There are 2 lymphatic
plexuses
• Superficial plexus (subpleural):
lies under the visceral pleura and
drains to bronchopulmonary nodes in
the hilum of lung.
• Deep plexus:
• Lies along the bronchial tree &
pulmonary blood vessels and drain
into the pulmonary nodes within the
lung substance. Then into
bronchopulmonary nodes in the
hilum of lung. Then into the
tracheo-bronchial nodes at the
bifurcation of trachea, and finally
into broncho-mediastinal lymph
trunks to end in thoracic duct (left)
or in right lymphatic duct (right).
Lymph Drainage of
the Lung
DARWISH BADRAN

The trachea divides into 2
main bronchi:
• Right main bronchus:
divides before entering the
hilum, it gives off superior lobar
(secondary) bronchus.
On entering hilum, it divides into
middle & inferior lobar bronchi.
• Left main bronchus:
it divides after entering the lung
into superior & inferior lobar
bronchi.
Within the lung each
bronchus divides into
number of branches.
Bronchi
DARWISH BADRAN

They are the anatomic, functional, and
surgical units of the lungs.
Each lobar (secondary) bronchus gives
off segmental (tertiary) bronchi.
Each segmental bronchus divides
repeatedly into bronchioles.
Bronchioles divide into terminal
bronchioles, which show delicate
outpouchings ‘the respiratory
bronchioles’.
Bronchopulmonary Segments
DARWISH BADRAN

The respiratory
bronchioles end by
branching into alveolar
ducts, which lead into
alveolar sacs.
The alveolar sacs consist
of several alveoli, each
alveolus is surrounded by
a network of blood
capillaries for gas
exchange.
DARWISH BADRAN

It is pyramidal in shaped, its apex lies
toward the root, while its base lies on
the lung surface.
It is surrounded by connective tissue
septa.
It has a segmental bronchus, a
segmental artery, lymph vessels, and
autonomic nerves.
The segmental vein lies in the inter-
segmental C.T. septa between the
segments.
A diseased segment can be removed
surgically, because it is a structural unit..
DARWISH BADRAN

HISTOLOGY OF THE CONDUCTING
SYSTEM
119

120
Upper
Respiratory
Tract
Lower
Respiratory
Tract

The Nose
123
A. THE NOSE -- a hollow
organ, covered with skin,
provided with muscles,
supported by cartilage and bone
and lined with a mucous
membrane (mucoperiosteum).
B. THE NASAL CAVITIES --
(separated by the nasal septum):

1. The vestibule -- opens to
the outside at the anterior
nares. The skin continues
into the vestibule; Changes
from epidermis of thin skin
to pseudostratified, ciliated,
columnar epithelium in the
rest of the nasal cavity. The
junction between the skin
and the mucous membrane
is known as the white line;
it has relatively low blood
supply.
124

2. The respiratory region -- includes nearly all of the
septum and lateral walls. The surface area of the lateral
walls is increased by shelf-like projections (supported
by bone) called conchae or turbinates.
125

a. Epithelium: pseudostratified, ciliated columnar
with goblet cells; Cilia beat backwards, toward the
pharynx; Goblet cells sometimes are concentrated
in intraepithelial pits; The basement membrane
varies from thin to very thick.
b. Lamina propria: of loose connective tissue; it
contains: mixed sero-mucous glands (comp.
tubuloalveolar) and a rich cavernous venous
plexus, which serves to warm the passing air; upon
irritation the plexus can be distended by blood and
reduces air flow; it is described as erectile tissue.
c. Submucosa: absent, the deepest layer of the
lamina propria fuses with the periosteum below;
126

The olfactory region -- located on the superior concha and adjacent septum (dime-size areas).
127

Olfactory Epithelium
1) Olfactory cells: spindle shaped, with round nuclei;
(Nuclei are in the middle and deep zone of the
epithelium.) the apical part extends to the epithelial
surface, ends in a bulbous knob which bears 6-8
olfactory hairs; these hairs or cilia are non-motile,
sensory and serve as dendrons; they are embedded in a
thick layer of mucus and parallel the surface of the
olfactory epithelium. The proximal (basal) part of the
cells form a long thin axonal process, which constitute
the olfactory nerve fibers; these unmyelinated fibers are
connected to the olfactory center of the brain (in the
olfactory bulbs). Olfactory cells are modified bipolar
neurons.
Functions: the olfactory cilia are stimulated by gaseous,
odori-ferous substances dissolved in the secretion of
serous glands moistening the epithelium.
128

SEM of the surface of the Olfactory Epithelium

2) Supporting cells: tall
slender cells make up the
upper third of the
pseudostratified epithelium
(nuclei in top 2-3 rows). They
are attached to the sensory
(olf.) cells at the surface of
the epithelium by zonula
adherens (junctional
complex with terminal web).
Have a small Golgi complex
in the apical cytoplasm and
pigment granules (brown).
There are numerous slender
villi on their apical surface.
130

3) Basal cells:
constitute a single
layer of conical
elements a the
base of supporting
cells (bottom layer
of nuclei); have
dark nuclei and
branching
processes.
131

Lamina propria: continuous with
the dense connective tissue of the
underlying periosteum in the adult
or with the perichondrium in the
fetus. The venous plexus in the
lamina propria is continuous with
that of the respiratory regions.
A group of branched,
tubuloalveolar (mainly serous)
olfactory glands called Bowman's
glands present in the lamina
propria supply the necessary
solvents to trap odoriferous
substances. The continuous
replacement of secretion keeps the
receptors ready for new stimuli.
132

Thin walled tube 10 cm long
Bifurcates into 2 primary bronchi
Respiratory mucosa
C-shaped hyaline cartilage rings with open ends
connected by elastic ligament and smooth muscle
(Trachealis); contraction occurs in coughing to
increase velocity of air
TRACHEA
134
Trachealis

Bronchial Tree
2 primary bronchi enter
lungs
3 intrapulmonary bronchi
on right and 2 on the left
Bronchioles
Terminal bronchioles
136

> 5 mm diameter
Mucosa and submucosa like trachea
Smooth muscle, elastic fibers, and
serous/mucous glands in lamina propria
Lymphoid nodules may be present in
lamina propria
Hyaline cartilage present in interrupted
plates.
BRONCHI
137

Pseudostratified columnar epithelium ciliated with goblet cells.
Lies on relatively thick basement membrane.
Contains 5-6 types of cells:
1) Goblet 2) Ciliated columnar 3) Basal
4) Brush 5) Serous?? 6) DNES
140

1) Goblet cells
Form 30% of total cells.
Secrete mucinogen which becomes mucin on
hydration. They can absorb water in < 20ms.
The part containing secretory granules is
known as the theca.
The basal part is called the stem.
Cytoplasm contains: rER, Golgi, ribosomes,
mitochondria.
Apical plasmalemma shows microvilli.
141
Stem
Theca

2) Ciliated columnar cells
Form ~35% of total cells.
Have basally located nucleus.
Posses cilia and microvilli.
Apical cytoplasm is rich in mitochondria
and Golgi apparatus.
Basal cytoplasm is rich in rER.
They move the mucus upwards
142

3) Basal (Stem) cells
Considered as stem
cells.
Relatively short, with
large round-oval
nucleus
Might replace goblet,
columnar and brush
cells.
143

4) Brush cells
Columnar cells with
microvilli.
Unknown function.
Cytoplasm contains small
mucus granules.
144

5) DNES
145
Form 3-4% of total cells.
Basal cytoplasm contains several granules.
Granular content usually released into nearby connective tissue.
They secrete substances that control the functions of other cells.
It is believed that their processes into the lumen monitor the O2 & CO2 levels in the lumen.
Can be seen in immuno-stained sections only

Dome-shaped cells with microvilli.
Apical cytoplasm contains granules and many
rER.
Their secretion protects bronchiolar
epithelium.
They detoxify certain toxins in the sER.
They secrete surfactant like substance.
They divide to replace degenerated
bronchiolar epithelium.
146
Clara cells
They start to appear from the
carina, and increase in number
distally.

Pneumocytes type I
Simple squamous epithelial cells with
tapering ends forming 90% of
alveolar surface.
Has a well developed basal lamina.
Nucleus seen in the widest arts of the
cell surrounded by organelles.
Form occluding junctions with each
other and with type II.
147

Pneumocytes type II
More numerous than type I but occupy
less surface area.
They are cuboidal cells located in the
interalveolar septum (septal cells).
Have apical microvilli, central nucleus,
rER,Golgi, and mitochondria.
Lamellar bodies are frequent and secrete
the surfactant.
These cells replace degenerated type I
cells.
148

Alveolrar
Macrophages
Originate from blood monocytes.
Enter the alveolar lumen between alveolar cells.
They maintain sterile environment by
phaocytosing foreign bodies.
They assist in uptake of surfactant.
They migrate to bronchi and they either return to
alveoli or become swallowed or expectorated.
They may migrate into lymph vessels.
149

Terminal Bronchioles
The smallest and the most distal of the
conducting system.
Less than 0.5 mm in diameter.
Epithelium is composed of Clara cells and
cuboidal ciliated cells.
Lamina propria is composed is composed of
fibroelastic connective tissue surrounded by 1-2
layers of smooth muscles.
NO goblet cells, NO cartilage, No glands in the
lamina propria.
150

Respiratory
Bronchioles
The first region for gaseous exchange.
Their wall is interrupted by alveoli. Transition
between conducting and respiratory tissues
Ciliated cuboidal epithelium with Clara cells
changes to type 1 alveolar cells
Smooth muscle and elastic fibers underlie
epithelium (parasympathetic stimulation:
bronchial constriction; sympathetic stimulation:
bronchial dilation)
151

Alveolar Ducts
There is no wall, but
alveoli arranged in one
line.
Each alveolar duct
branches and ends in an
alveolar sac.
The beginning of the
alveolar sac is known as
atrium.
152

Alveoli
The primary
histological and
functional units of the
respiratory system.
Total number of
alveoli is ~ 300
million covering ~
150 m2.
153

The interalveolar septum
occupies the region between two
adjacent alveoli.
Each (face) is lined by alveolar
epithelium.
Its thickness is extremely variable.
It contains continuous capillaries,
collagen type III, elastic fibres,
fibroblasts, mast cells, and lymphocytes.
154

The Blood-Air Barrier (BAB)
It is the region where the
interalveolar septum septumis
traversed by respiratory gases.
It is composed of:
• Surfactant
• Type I pneumocytes
• Fused basal lamina
• Endothelium.
155

Lamina Propria
Goblet Cells
Basal Lamina

Smooth muscles
Seromucous glands
Hyaline cartilage

Terminal Bronchiole Smooth Muscles

Pulmonary vein
Cartilage
Lung tissue
Smooth muscles
Pulmonary artery
Glands

Terminal Bronchiole
Respiratory Bronchiole
Alveolar Duct
Alveolar Sac
Alveolus
Pleura

Bronchus
Bronchiole
Pulmonary artery
Bronchial artery

Alveolar type I
Alveolar type II

Respiratory system Anatomy

Recomendados

Recomendados

Más contenido relacionado

La actualidad más candente

La actualidad más candente (20)

Destacado

Destacado (20)

Similar a Respiratory system Anatomy

Similar a Respiratory system Anatomy (20)

Último

Último (20)

Respiratory system Anatomy