The document provides an overview of the anatomy and structure of the respiratory system, with a focus on the anatomy of the lungs. It describes the major parts and structures of the respiratory system including the nose and nasal cavity, pharynx, larynx, trachea, bronchi, and lungs. It discusses the lobes and lobules of the lungs, the alveoli where gas exchange occurs, and the pleural membranes that surround the lungs.

1. ANATOMY OF RESPIRATORY SYSTEM
(with special reference to anatomy of lungs)

2. 1. Parts of Respiratory system
2. Structural classification
3. Nose and nasal cavity
4. Pharynx
5. Larynx
6. Trachea
7. Bronchi
8. Lungs
a. Pleural membrane
b. Lung surfaces
c. Lobes ,fissures and lobules
d. Alveoli

3. SOURCE: Ross and Willson Anatomy and Physiology in health and illness ,242
PARTS OF RESPIRATORY SYSTEM
And associated structures

4. STRUCTURAL CLASSIFICATION
UPPER RESPIRATORY SYSTEM LOWER RESPIRATORY SYSTEM
Nose
Nasal Cavity
Pharynx
Larynx
Trachea
Bronchi
Lungs

5. NOSE AND NASAL CAVITY

6. NOSE
EXTERNAL NOSE NASAL CAVITY
• Supporting framework if bone
 frontal bones
 Nasal bones
 Maxilla
• Cartilaginous framework
 Septal nasal cartilage(anterior portion)
 Lateral nasal cartilages(inferior portion)
 Alar cartilages(walls of nostril)
• Covered with muscle and skin
• Lines by mucous membrane
• External nares (nostrils)
• Nasal vestibules
Leading to
Functions of interior
structure of external
nose
1. Warming ,moistening and
filtering incoming air
2. Detecting
olfactory stimuli
3. Modifying speech
vibrations as they pass
through the resonating
chambers

7. Nasal cavity
Right
nasal
cavity
Left
Nasal
cavityNasal
bone
Oral
cavity
Anterior :
hyaline
cartilage
Remainder:
Vomer
Perpendicular
plate of ethmoid
Maxillae
Palatine bone
Merges
with
external
nose
Communic
ate with
pharynx
(through
internal
nares)
Lateral wall Floor
Ethmoid Palatine bones
Palatine Palatine processes of
maxillae
Lacrimal Hard palate
Maxillae
Inf. Nasal conchae
bones
NASAL MUCOSA
• A mucous membrane that air passes over , it has a rich blood supply.
a) :
b) Paranasal sinuses: four pairs of air containing spaces that open into
nasal cavity and each is lines with respiratory mucosa.
Olfactory
nerve cells
Lymphatic
plexus
Olfactory
epithelium
NASAL CAVITY
ANTERIORLY POSTERIORLY

8. FUNCTIONS :
1. Exchanges small amount of air
with auditory tube to equalize
pressure between pharynx and
middle ear (NASOPHARYNX).
2. Serves as common passageway
for air, food and drink
(OROPHARYNX).
3. Provides the resonating
chamber for speech sounds.
4. Houses the tonsils.
5. Participates in immunological
reactions against foreign
invaders.
PHARYNX

9. • Lies posterior to nasal
cavity and extends to
the soft palate .
• It has 5 opening in the
walls:
1. Two internal nares
2. Two openings that
lead to auditory tube
3. Opening into
oropharynx
• Intermediate portion of
pharynx.
• Lies posterior to internal
cavity.
• Extends from soft palate
inferiorly to the level of
hyoid bone
• Only one opening (fauces)
into the throat.
• Hypopharynx
• Begins at the level of hyoid
bone.
• Opens into :
a) Oesophagus posteriorly
b) Larynx anteriorly

10. LARYNX
FUNCTIONS:
1. Airway to lungs.
2. Produces voice
3. Connects
laryngopharynx with
trachea.

11. • Larynx is a short passageway lying in
the midline of the neck anterior to
the oesophagus and the fourth to
sixth cervical vertebra (C4-C6).
• Walls of larynx and nine piece of
cartilages:
 Arytenoid cartilages influence
changes in position and tension of
the vocal folds.
• The cartilages are lined by a ciliated
mucous membrane which forms two
pairs of folds:
1. VESTIBULAR (FALSE)VOCAL CORDS:
They hold breath against pressure in
the thorasic cavity.
2. TRUE VOCAL CORDS:Inferior pair
,responsible for voice production.
• Vocal folds re thicker and longer in
males than females due to influence
of androgen and hence man’s voice
has lower pitch compared to woman.
Cartilages
1. Thyroid
2. Epiglottis
3. Cricoid
1. Aytenoid
2. Cuneiform
3. Corniculate
3 paired
small
cartilages

12. TRACHEA

13. • The trachea (windpipe) extends from the larynx to the primary bronchi ,fifth thorasic
vertebra (T5)
• composed of C-shaped rings of cartilageous and smooth muscles.
• Lined with pseudostratified ciliated columnar epithelium
• It is about 12 cm(5 inch) long and 2.5 cm (1inch ) in diameter.
LAYERS OF TRACHEAL WALL:
MUCOSA SUBMUCOSA HYALINE CARTILAGE ADVENTITIA
Epithelial layer of
pseudostratified ciliated
columnar epithelium
and underlying layer of
lamina propria that has
elastic and reticulate
fibers.
Areolar connective
tissue that contains
submucous glands and
their ducts .
16-20 incomplete ,
horizontal rings of
hyaline cartilage
,resembling letter C and
are stacked one on top
of other .
Their opening part faces
esophagus.
Composed of areolar
connective tissue and
joins trachea to
surrounding tissue.

14. BRONCHI

15. TRACHEA
(at T5)
Left lung Right lung
Secondary
bronchi
Tertiary
bronchi
Bronchioles
Alveolar ducts
LEFT PRIMARY BRONCHUS RIGHT PRIMARY BRONCHUS

16. LUNGS
• Lungs are paired cone
shaped organs in the
thorasic cavity .
• They are separated
from each other by
heart and other
structures in
mediastinum – which
divides the thorasic
cavity into two
anatomically distinct
chambers .
FUNCTIONS:
1. Air distribution
2. Gas exchange (alveoli)

17. Pleural membrane Lung surfaces
• Two collective layers of serous membrane
subdivided as :
1. PARIETAL PLEURA: superficial layer , lines
thorasic cavity’s wall.
2. VISCERAL PLEURA: deep layer that cover lung
itself.
Pleural cavity: space between visceral and parietal
pleura containing fluid secreted by membranes .
FUNCTIONS OF PLEURAL FLUID:
a) Reduces friction between the membranes .
b) Allows membrane to slide easily over one
another during breathing.
c) Membrane adherence.
Pleurisy/pleuritis : inflammation of pleural
membrane.
Pleural effusion: accumulation of excess fluid in
pleural space .
1. BASE: broad inferior portion of the lung , concave ; fits
over convex area of diaphragm .
2. APEX: narrow superior portion of the lungs.
3. COSTAL SURFACE : surface of lung lying against the ribs .
4. MEDIASTINAL SURFACE: medial surface containing hilum
Hilum : region through which bronchi , pulmonary blood
vessels ,lymphatic vessels and nerves enter and exit.
They are held together by pleura and connective tissue and
constitute the root of the lungs.
Cardiac notch : concavity in left lung where heart lies.
Left lung is 10% smaller
than right lung
Right lung is thicker, broader
and shorter than left lung
(due to diaphragm being
higher on right side.

18. Lobes, fissures and lobules
• Both lungs have oblique fissure which extends inferiorly
and anteriorly , right lung also has horizontal fissures .
• Oblique fissure in the left lung separates the superior
lobe from the inferior lobe.
• In the right lung ,the superior part of oblique fissure
separates the inferior lobe from the superior lobe ; the
inferior part of oblique fissure separates the inferior
lobe from the middle lobe which is bordered superiorly
by horizontal fissures .
• Each lobe receives its own secondary bronchus .
• Right primary bronchus gives rise to superior ,middle
and inferior secondary bronchus .
• Left primary bronchus gives rise to superior and inferior
secondary bronchus.
• There are 10 tertiary bronchi in each lung and the
segment of lung tissue supplied by them is called
bronchopulmonary segment .
• Each of these segments have small compartments
called lobules that contain a lymphatic vessel, an
arteriole, a venule and a branch from terminal
bronchiole.

19. ALVEOLI
• Present around the
circumference of the
alveolar ducts .
• An alveolus is a cup shaped
outpouching lined by
simple squamous
epithelium and supported
by a thin elastic basement
membrane .
• Main function is exchange
of gases.
• Surfctant is present in
alveolar fluid
(phospholipids and
lipoproteins ), to lower the
surface tension of alveolar
fluid ,which reduces
tendency of alveoli to
collapse.
Structure of the alveolus.

20. Alveolar
cells
Type-I Type-II
Simple squamous
epithelial cells
that form a
nearly continuous
lining of the
alveolar wall.
Septal cells that
are rounded or
cuboidal epithelial
cells with free
surfaces containing
microvilli ,secrete
alveolar fluid to
keep surface
moist.
Extending from alveolar air space to blood
plasma :
1. Alveolar wall: A layer of type I and type II cells
and associated alveolar macrophages.
2. Epithelial basement membrane : underlying
the alveolar wall.
3. Capillary basement membrane: fused to the
epithelial basement membrane.
4. Capillary endothelium
• Respiratory Membrane is 0.5 micrometers
thick .
• Lungs contain 300 million alveoli ,providing
surface area of
70m2.

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