ANATOMY OF RESPIRATORY SYSTEM

1. THE
RESPIRATORY
SYSTEM
BY:
MRS.KEERTHI SAMUEL,
ASST.PROFESSOR,
VMCON

2. INTRODUCTION

3. CLASSIFICATION-STRUCTURAL
UPPER RESPIRATORY TRACT LOWER RESPIRATORY TRACT

4. CLASSIFICATION-FUNCTIONAL
CONDUCTING ZONE RESPIRATORY ZONE

5. OTO-RHINO-LARYNGOLOGY

6. ANATOMY
OF THE
NOSE

7. NOSE IS DIVIDED INTO
EXTERNAL NOSE INTERNAL NOSE

8. EXTERNAL NOSE
BONY FRAMEWORK CARTILAGENOUS FRAME WORK
FRONTALL
OR ALAR.C
EXTERNAL NARES
NASAL
CARTILAGE
OR ALAR
CARTILAGE

9. FUNCTIONS
Warming,
moistening and
filtering of
incoming air
Detect
olfactory
stimuli
Modify
speech
vibrations and
resonance

10. INTERNAL NOSE
Large cavity in the
• anterior aspect of the skull.
• Inferior to the nasal bone
• Superior to the mouth
Covered by muscle and mucous memebrane
Anteriorly merges with ext.Nose
Posteriorly opens into pharynx
through 2 openings called
CHONAE/INTERNAL NARES

11. INTERNAL NOSE
1. Lateral wall- Ethmoid,Maxilla
2. Roof - Ethmoid bone
3. Floor – Palatine bones of Maxilla
Space in the int. nose is called Nasal
cavity.
The anterior part of internal
nostrils- VESTIBULE.

12. INTERNAL NOSE
•Nasal septum , a vertical partition
divides nasal cavity into right and left
halves.
•When air enters into the nostrils it first
enters into the vestibule, that is lined
by skin containing coarse hairs that
filters out large dust particles.

13. INTERNAL NOSE-
MEATUS
•The projections of superior, inferior and
middle CONCHAE forms three shelves which
subdivides the nasal cavity into:
1. SUPERIOR MEATUS: olfactory receptors
2. MIDDLE MEATUS
3. INFERIOR MEATUS Lined by mucous
membranes which traps the water during
inhalation to prevent drying.

14. OLFACTORY
EPITHELIUM
Inferior to the olf.epithelium there are capillaries and
pseudostratified ciliated columnar epithelium+ GOBLET
CELLS which traps dust and moistens air.
CILIA- Moves trapped dust particles towards pharynx
thus allowing us to swallow and hence dust is removed
from respiratory tract.

15. ANATOMY
OF
PHARYNX

16. PHARYNX/THROAT
•Funnel shaped tube.
•Length-13cms.
•Starts at interal nares and extends to
the lecel f cricoid cartilage , the most
inferior cartilage of larynx.
•POSITION: posterior to nasal and
oral cavities, superior to larynx, just
anterior to cervical vertebrae.
•Wall is composed of skeletal muscles
and is lined by mucous membrane.

17. FUNCTIONS OF PHARYNX
Deglutition
Respiration
Vocal resonance
Secretion of mucus for
lubrication
Provides drainage of nose,
oral cavity, middle ear
Houses tonsils

18. DIVISION AND
MUSCLES OF
PARYNX
The muscles of pharynx are
arranged into:
◦ Outer circular layer
◦ Inner longitudinal layer
◦ The superior portion of pharny is
called NASOPHARYNX- which
lies posterior to the nasal cavity
and soft palate.

19. OPENINGS OF
PHARYNX
There are 5 openings in the wall of pharynx:
•2 internal nares
•2 auditory/Eustachian tubes.
•1 opening into oropharynx.
•The posterior wall has –PHARYNGEAL
TONSIL

20. NASOPHARYNX
qReceives air from nasal cavity
along with packages of dust laden
mucus.
qLined by pseudostratified ciliated
columnar epithelium- cilia moves
mucus downwards to the inferior
part of pharynx

21. OROPHARYNX
Intermediate portion.
Lies posterior to oral cavity and extends from soft
palate inferior to the level of hyoid bone.
It has only one opening called FAUCES the
opening from mouth.
It has both digestive and respiratory functions
which is a common passage for air ,food and
drink.

22. OROPHARYNX
Because oropharynx is subjected to abrasion
by food particles- it is lined by non keratinized
stratified squamous epithelium.
Two pairs of tonsil are housed : PALATINE
AND LINGUAL TONSILS.

23. LARYNGOPHARYNX/
HYPOPHARYNX
qBegins at the level of hyoid bone.
qOpens posteriorly into esophagus and
larynx anteriorly
qBoth respiratory and digestive fuctions
hence lined by non keratinized stratified
squamous epithelium.

24. ANATOMY
OF LARYNX

25. LARYNX-LOCATION
Short passageway that connects
laryngopharynx with the trachea.
Lies in the midline of neck anterior to
esophagus and through (C3-C6) cervical
vertebrae.

26. Aretynoid influences change in the position and tension
of vocal cords.

27. 1.THYROID CARTILAGE/ADAM’S APPLE
o2 fused plates of hyaline cartilage that
forms anterior wall of larynx and gives it a
triangular shape.
oPresent both in males and females , but
larger in males due to male sex hormone
on its growth during puberty.
oTHYROHYOID MEMBRANE - connects
thyroid cartilage with hyoid membrane.

28. 2.EPIGLOTTIS
oLarge leaf shaped piece of elastic cartilage that is covered
with epithelium.
oThere are 2 parts
STEM: Tappered inferior portion
attached to the rim of thyroid
cartilage
LEAF-Broad superior portion-
unattached and is free to move up
and down like a trap door

29. 2.EPIGLOTTIS
oDuring swallowing the pharynx and larynx rise .
oElevation of pharynx widens it to receive food and drink.
oElevation of larynx causes epiglottis to move downward and
form a lid over GLOTTIS, closing it off.
oThe closing of larynx in this way during swallowing routes
liquids and foods into esophagus and prevents into larynx.
oWhen a small particle of dust ,smoke or liquid passes into
larynx , a cough reflex occurs , usually expelling the material.
2.EPIGLOTTIS
GLOTTIS

30. LARNYX
3.CRICOID CARTILAGE
It’s a ring of hyaline cartilage that forms
the inferior wall of larynx.
CRCICOTHYROID LIGAMAENT:
attached to the first ring of trachea
connecting the cricoid to thyroid
cartilage.
Site for emergency tracheostomy
4. ARYTENOID
CARTILAGE
Triangular pieces of mostly hyaline
cartilage located to posterior,
superior boarder of cricoid
cartilage.
Supported by arytenoid cartilage ,
the intrinsic muscles of pharyngeal
muscle contract and move vocal
cords to produce sound.

31. LARNYX
5.CUNEIFORM CARTILAGE
Club shaped elastic cartilage anterior to corniculate cartilage
Supports the vocal cords and lateral aspects of epiglottis.
Horn shaped pieces of cartilages located at the apex of each
arytenoid cartilage .
They are the supporting structures of epiglottis.
4. CORNICULATE CARTILAGE

32. VOCAL CORDS
The mucous membrane of larynx forms 2 pairs of folds:
 The superior pair- FALSE VOCAL CORDS/VENTRICULAR
FOLDS
 The inferior pair - VOCAL FOLDS/TRUE VOCAL CORDS-
principle structures of voice production.
 The space between ventricular folds is known as RIMA
VESTIBULI.
When ventricular folds are brought together they function in
holding the breath against pressure in thoracic cavity (Ex: strain
while lifting heavy object)

33. VOCAL CORDS
When the intrinsic muscles of larynx contract there will be
abduction of vocal cords.
When the muscles relax – adduction of vocal cords –
production of sound-PITCHED.
Whispering do not cause closure of vocal cords or they donot
vibrate.

34. TRACHEA/WIND PIPE
•Tubular passage way for air . Length is about 12cms and width is
2.5cms
•Located anterior to esophagus and extends from larynx to T5 and
then divides into right and left bronchi.
•It provides protection against dust.

35. TRACHEA-layers
MUCOSA
• Pseudostratified ciliated
columnarepithelium+ goblet
& basal cells
• Protects against dust
SUBMUCOSA
• Areolar connective
tissue.
• Contains sero-mucus
glands and ducts.
HYALINE CARTILAGE
• 16-20 incomplete
horizontal rings
resemble letter ‘C’ and
are stacked one above
the other

36. TRACHEA/WIND PIPE
•Rings are felt through skin inferior to larynx.
•Open part of C shaped cartilages faces esophagus- this
arrangement accommodates slight expansion of esophagus into
trachea during swallowing
•Transverse smooth muscle fibers –trachealis muscle and elastic
tissue stabilize the open ends of cartilaginous rings.
•The solid C shaped rings provide semirigid support so that tracheal
wall does not collapse inward and obstruct

37. BRONCHI
At the superior boarder of 5th thoracic vertebra, the trachea
divides into:
• RIGHT PRIMARY BRONCHUS- More vertical ,shorter
and wider than LEFT PRIMARY BRONCHUS.
• Hence the aspirated object is likely to enter and lodge
into right primary bronchus than the left.
• Like trachea the primary bronchus contain incomplete
rings of cartilage and are lined by pseudostratified
ciliated columnar epithelium.

38. BRONCHI
•The point where trachea divides into right and left primary
bronchi there is an internal ridge called ‘CARINA.’
•The mucous membrane of carina is one of the most sensitive
areas of entire larynx and trachea for triggering a cough
reflex.
•Widening and distortion of carina is a serious sign because it
usually indicates a carcinoma of lymphnodes around region
where trachea divides.

39. BRONCHAL TREE
PRIMARY BRONCHI divides into
smaller bronchi
SECONDARY BRONCHI(LOBAR)-1 for
each lobe of lung.
TERITIARY (SEGMENTAL)
BRONCHIOLES
TERMINAL BRONCHIOLES-smallest
tubes.
IT LOOKS LIKE AN INVERTED TREE , ITS CALLED BRONCHIAL TREE

40. ANATOMY
OF LUNGS

41. LUNGS
•Paired, cone shaped organs in the thoracic cavity.
•They are separated from each other by the heart and
other structures in mediastinum, which divides the
thoracic cavity into 2 anatomically distinct chambers.
•Two layers of serous membranes collectively called
PLEURAL MEMBRANE enclose and protect each
lung.

42. LUNGS- PLEURA
•PARIETAL PLEURA- Superficial layer, lines the wall of the
thoracic cavity.
•VISCERAL PLEURA – deeper layer and covers the lungs
themselves.
•Between the visceral and parietal pleura there is a small place
called PLEURAL CAVITY- contains small amount of lubricating
fluid called PLEURAL FLUID secreted by the membrane
allowing them to slide easily over one another during breathing

43. LUNGS- PLEURA
•Pleural fluid also causes the two membranes to one another
just as a film of water causing two layers to slide and stick
together , a phenomenon called ‘SURFACE TENSION’
•Separate pleural cavities surround the left and right lungs.
•Inflammation of pleural membranes is called PLEURITIS.
•Accumulation of fluid in pleural space is called PLEURAL
EFFUSION.

44. LUNGS- PARTS
•The lungs extends from diaphragm to just slightly superior
to the clavicles and lies against the ribs anteriorly and
posteriorly.
•The broad inferior portion of the lung- BASE-concave and
fits over the convex area of diaphragm.
•The narrow superior portion of the lung-APEX

45. LUNGS- SURFACES
•1. COASTAL SURFACE –Matches the rounded curvature
of ribs.
•2. MEDIASTINAL SURFACE- Contains a region called
hilum through which bronchi, pleural blood vessels,
lymphatic vessels and nerves enter and exit.
•Medially left lung contains concavity the CARDIAC NOTCH
in which the heart lies.

46. LUNGS
•Due to the space occupied by the heart ,the left lung is about
10% smaller than the right lung.
•Although the right lung is thicker and broader ,it is somewhat
shorter than the left lung because the diaphragm is higher on
right side, accommodating the liver that lies inferior to it.
•The lungs fills the thorax and is the only area that can be
palpated

47. LUNGS
•The base of the lung extends from the 6th intercostal
cartilage anteriorly to spinous process of 10th thoracic
vertebra posteriorly.
•The pleura extends about 5cms below its base – 6th
costal cartilage anteriorly and 12th rib posteriorly.
•Thus the lungs donot completely fill the pleural cavity in
this area.

48. LUNGS- LOBES,FISSURES, LOBULES
•One or two fissure divide each lung into lobes.
•Both the lungs has OBLIQUE FISSURE, which extends inferiorly
and anteriorly.
•Right lung has –HORIZONTAL FISSURE.
•OBLIQUE FISSURE- divides left lung INTO SUPERIOR AND
INFERIOR LOBE.
•In the right lung the superior part of oblique fissure separates the
superior lobe from the inferior lobe .
•The inferior part of the oblique fissure separates the inferior lobe
from middle lobe.

49. LUNGS- BRONCHI
Each lobe receives its own secondary bronchus: thus
right bronchus gives the secondary bronchi ( Superior,
middle and inferior lobar bronchi)
Within the lung secondary bronchi gives rise to tertiary
bronchi (approx. 10 tertiary bronchi are seen in each lung).
The segment of lung tissue that each tertiary bronchus
supplies is called ‘BRONCHO-PULMONARY SEGEMENT’

50. LUNGS- BRONCHI
 Each segment of lungs has many compartments called
LOBULES.
Each lobule is wrapped in elastic connective tissue and
has lymphatic vessels, arterioles, venule and a branch
from terminal bronchiole----------- divides into REPIRATORY
BRONCHIOLES which subdivide into ALVEOLAR DUCTS.

51. ALVEOLI

52. ALVEOLI
Around the circumference of the alveolar ducts are
numerous alveoli and alveolar sacs.
An ALVEOLUS is a cup shaped outpouching lined
by simple squamous epithelium and supported by
a thin elastic basement membrane.
An alveolar sac consists of two or more alveoli that
share a common opening.

53. ALVEOLI-CELLS
 The walls of alveoli consists of two types of alveolar
epithelial cells:
1. TYPE –I ALVEOLAR CELLS: simple squamous epithelial
cells that form a nearly continuous lining of the alveolar
wall.
• The thin type –I alveolar cells are the main sites for
gaseous exchange.
2. TYPE-II or SEPTAL CELLS: fewer in number and are
found between type-I cells.
• Rounded or cuboidal epithelial cells with free surfaces
containing microvilli which secrete alveolar fluid.

54. ALVEOLI-CELLS
 The alveolar fluid keeps the surface between the cells and
the air moist.
 Included in the alveolar fluid is SURFCTANT, a complex
mixture of phospholipids and lipoproteins.
 Surfactant lowers the surface tension of the alveolar fluid ,
which reduces the surface tension of alveolar fluid and
reduces the tendency of alveoli to collapse thus maintains
the patency.

55. ALVEOLI-CELLS
 Associated with the alveolar wall are ALVEOLAR
MACROPHAGES /DUST CELLS-phagocytes that remove
fine dust particles and other debris from the alveolar spaces.
 Also there are fibroblasts that produce reticular and elastic
fibers
 Underlying the layer of type-I cells is an elastic basement
membrane
 On the outer surface of the alveoli the lobules arteriole and
venules forms a network of capillaries .

56. RESPIRATORY MEMEBRANE
 The exchange of gases takes place across the alveolar and
capillary walls, which together forms the RESPIRATORY
MEMBRANE which is composed of four layers.
1. A layer of type-I and Type-II alveolar cells ad associated
alveolar macrophages that constitutes the alveolar walls.
2. An EPITHELIAL BASEMENT MEMBRANE underlying the
alveolar wall.
3. A CAPILLARY BASEMENT MEMBRANE that is often
fused to the epithelial basement membrane.
4. The CAPILLARY ENDOTHELIUM

57. RESPIRATORY MEMEBRANE
Despite having several layers the respiratory
membrane is very thin only 0.5 micrometers
thick, to allow rapid diffusion of gases.
It has been estimated that the lungs contain
300million alveoli, providing an immense surface
area of 70m2-about the size of racquet court for
gs exchange