anatomy of respiratory system

1. ANATOMY OF
RESPIRATORY
SYSTEM
PRESENTED BY: DR.JAGADISH JENA
DEPT.OF ANAEST. & CRITICAL CARE
VSS MCH BURLA,SBP

2. RESPIRATORY SYSTEM CONSISTS OF :
>UPPER RESPIRATORY TRACT(NOSE TO
LARYNX)
>LOWER RESPIRATORY TRACT(TRACHEA
ONWARDS)
CAN ALSO BE DIVIDED IN TO:
>Conducting portion transports air.
- Includes - Nose
Nasal cavity
Pharynx
Larynx
Trachea
From the primary bronchi to the terminal
bronchioles
>Respiratory portion carries out gas exchange.
- Composed of small airways called respiratory bronchioles
and alveolar ducts as well as air sacs called alveoli .

4. Nose
 Provides airway
 Moistens and warms air
 Filters air
 Resonating chamber for speech
 Olfactory receptors

5. EXTENAL NOSE
*Its upper one third is bony and lower two third are cartilaginous
*Bony part consists of two nasal bones which meet in midline.
*Cartilaginous part consists of
-Upper lateral cartilage:extends from under surface of nasal bones above to
alar cartilages below.
-Lower lateral cartilage(alar cartilage):it s u shaped
-Lesser alar cartilage(sesamoid):lie above and lateral to alar cartilages.
-Septal cartilage
*Muscles of nose: Procerus,nasalis,levator labii superioris,alaque nasi,ant. And post.
dilator nares,depressor septi.
These muscles help in movement of nose.

7. INTERNAL NOSE
Divided in to –Vestibule of nose
-Nasal cavity proper
Vestibule of nose: Ant. and inferior part of nasal cavity
lined by skin and contains sebaceous
glands,hair follicles and hair called vibrissae

8.  Nasal cavity proper: It has lateral wall
medial wall
floor
roof
*Lateral wall: Marked by three scroll like bony projections called turbinates or
conchae,known as inferior,middle,superior from below upwards
: Below and lat.to each turbinate corresponding meatus present.
>Inferior meatus -nasolacrimalmal duct opens in to it
>Middle meatus-maxillary sinus,frontal sinus,ant.ethmodal sinus opens in
to it.
>Superior meatus-post.ethmoidal sinus opens in to it
Sphenoid sinus opens in to sphenoethmoidal recess.

10. APPLIED ANATOMY:
1-The inferior turbinate usually limits size of nasotracheal tube
2-Prolonged nasotracheal intubation has most often
associated with infection of maxillary sinus
*Medial wall: Nasal septum form the medial wall
:Has highly vascular little’s area in the antero inferior part of nasal
septum
APPLIED ANATOMY:
1-This is the commonest site of epistaxis
2-As it is highly vascular,nasal vasoconstrictor is used to shrink the mucosa and
dilate airway during nasotracheal intubation.

11. *Floor: Formed by palatine process of maxilla,palatine bone
: Almost perpendicular to the plane of face.so tube should be inserted
perpendicular to the plane of face.
*Roof: Formed by nasal bones sphenoid bone,cribiformplate of ethmoid
APPLIED ANATOMY:
1-Disruption of cribiform plate leads to csf rhinorrhea,is a contraindication for
positive pressure ventilation as it m leads to entry of infection.
2-Is also contraindication for nasotracheal intubation,nasogastric tube
insertion.

12. LINING OF NOSE:
Vestibule- Lined by stratified squamous epithelium
Respiratory region- Lined by pseudostratified ciliated columnar
epithelium
NERVE SUPPLY:
a-Olfactory nerves
b-Nerves of common sensation-ant.ethmoidal
nerve,sphenopalatine nerve,infra orbital nerve
c-Autonomic nerves

13. BLOOD SUPPLY:
Both the internal and external carotid system supply nose.
ORAL CAVITY
*Extends from mouth opening to ant.tonsillar pillar
*Tongue is a muscular organ which makes up most of the floor of oral
cavity
* Tongue has the habit of falling back on the oro pharynx & block the air
passage,whenever the muscle tone is decreased (Sleep, Decreased Level
of consciousness or General anesthesia ).
CLINICAL IMPORTANCE:
Mallampati grading helps in assessment of airway during PAC.

14. ORAL CAVITY
Mallampatti’s Classificaton
Faucial Pillar Uvula Soft palate Hard palate
Uvula Soft palate Hard palate
Soft palate Hard palate
Hard palate

15. APPLIED ANATOMY:
Previously it has been thought that upper airway obstruction occur due to
tongue fall but recently various studies shows that airway obstruction
occur mostly at the level of soft palate & epiglottis during sedation and GA.

16. PHARYNX
*It is 12-15 cm long.
*Widest at the level of hyoid bone,narrowest at the level of oesophagus.
*The wall of pharynx contain two layer of muscle-Circular(external)
-Longitudinal(internal)
*Internal layer muscles-Stylopharyngeus,salpingopharyngeus,palatopharyngeus
They elevate the pharynx and shortens the larynx during
deglution.
*External layer muscles-Superior constrictor,middle constrictor,inferior constrictor
They advance the food from oropharynx to oesophagus.
*The constrictors are innervated by pharyngeal plexus formed by-Vagus
-Glossopharyngeal
-External branch
of sup.laryngeal nerve
The inferior constrictor also innervated by recurrent laryngeal nerve.

17. *The internal layer innervated by glossopharyngeal nerve.
*The pharynx divided in to -Nasopharynx
-Oropharynx
-Laryngopharynx
*Nasopharynx- It extends from posterior nasal
aperature to the posterior
pharyngeal wall above the
soft palate.
APPLIED ANATOMY:
Adenoids are located in its roof – which are frequently hypertrophied during childhood &
may cause obstruction or hemorrhage while passing any tube through the nose.

18. * Oropharynx: Extends from soft palate to epiglottis
Most important area in terms of airway obstruction & management as it
is made of collapsible soft tissue all around.
*Laryngo pharynx: Extends from superior border of epiglottis to inferior border of
cricoid cartilage
WALDEYER’S RING
 The adenoid, palatine tonsil, Lingual tonsil & tubal tonsil form a somewhat continuous circle
of lymphoid tissue around the lumen of pharynx which is known as Waldeyer’s Ring.
 It helps in defensive mechanism of the respiratory and alimentary system by preventing the
entry of micro-organisms from the external enviroment.
CLINICAL IMPORTANCE:
1.This structure when infected & enlarged causes airway obstruction & impedes the passage
of nasotracheal tube.

19. 2.Lingual tonsil hypertrophy is usually asymptomatic,has ben
reported to cause unanticipated difficult intubation and fatal
airway obstruction.

20. LARYNX
*It lies in the midline of neck opposite C3 to C6 vertebra in adult & C1 to C4
vertebra in children.
* It extends from the upper border of epiglottis to lower border of cricoid cartilage.
*Measurements:
MALE FEMALE
Vertical Length - 44mm 36mm
Transverse diameter – 43mm 41mm
A-P diameter - 36mm 26mm
*The glottis is the narrowest part in adult.
*The subglottis(cricoid ring) narrowest part in children up to the age of 5 yrs.
APPLIED ANATOMY
That s why in children uncuffed endotracheal tube can be used.

21. *Larynx consists of 3 paired cartilages and 3 unpaired cartilages.
*Unpaired cartilages - Thyroid
- Cricoid
- Epiglottis
*Paired cartilages - Arytenoid
- Corniculate
- Cuneiform
*Thyroid cartilage is the largest cartilage
*Cricoid cartilage is the only complete cartilaginous ring in airway.

24. Muscles of larynx
Intrinsic muscles of larynx:
Muscle Function
1.Posterior cricoarytenoid 1.Abductor of vocal cords
2.Lateral cricoarytenoid 2.Adducts arytenoids closing glottis
3.Transeverse arytenoid 3.Adducts arytenoids
4.Oblique arytenoid 4.Closes glottis
5.Aryepiglottic 5.Closes glottis
6.Vocalis 6.Relaxes the cords
7Thyroarytenoid 7.Relaxes tension cords
8.Cricothyroid 8.Tensor of the cords

25. Extrnsic muscles of larynx:
Muscle Function
1.Sternohyoid 1.Indirect depressor of the larynx
2.Sternothyroid 2.Depresses the larynx
3.Thyrohyoid 3.Depresses the larynx
4.Thyroepiglottic 4.Inversion of aryepiglottic fold
5.Stylopharyngeus 5.Assists folding of thyroid cartilage
6.Inferior pharyngeal constrictor 6.Assists in swallowing

26. NERVE SUPPLY OF LARYNX
SENSORY – Above the vocal cord – Superior laryngeal nerve
Below the vocal cord - Recurrent laryngeal nerve
MOTOR – All intrinsic muscle of the larynx are supplied by RLN except
cricothyroid which is supplied by external laryngeal nerve which is a branch
of SLN.
Both SLN & RLN are branches of vagus nerve

28. ARTERIAL SUPPLY & VENOUS DRAINAGE
ABOVE THE VC - Superior laryngeal artery, a branch of superior thyroid
artery.
Superior laryngeal vein, drains into superior thyroid vein
BELOW THE VC – Inferior laryngeal artery, a branh of inferior thyroid artery.
Inferior laryngeal vein, drains into Inferoir thyroid vein.
LYMPHATIC DRAINAGE
ABOVE THE VC - Pre laryngeal & Jugulo – Digastric LN.
BELOW THE VC – Pre tracheal & Para tracheal LN.

29. Function of larynx:
1. Produces vocalizations (speech)
2. Provides an open airway (breathing)
3. Switching mechanism to route air and food into proper channels
 Closed during swallowing
 Open during breathing

30. APPLIED ANATOMY:
1.Effects of laryngeal nerve injury on the voice:
Sup.laryngeal nerve
unilateral minimal effects
bilateral hoarseness,tiring of voice
Rec.laryngeal nerve
unilateral hoarseness
bilateral: acute stridor,resp.distress
chronic aphonia
Vagus nerve
unilateral hoarseness
bilateral aphonia
2.In complete paralysis of both recurrent and SLN the cords are held in mid
position(cadaveric position)
3.Cords are also in cadaveric position during GA with muscle relaxants.

31. 4.Laryngoscopic view of larynx:

32. Cormack & Lehane graded laryngoscopic view as below which
helps in assessment of intubation:
Grd 1: Visualization of entire vocal cords
Grd 2: Visualization of posterior part of laryngeal apereture
Grd 3: Visualization of epiglottis
Grd 4: No glottic structure seen

33. Assesment of ease of intubation from grading:
Grd 1: No extrinsic manipulation of the larynx
required
Grd 2: External manipulation of the larynx is required
Grd 3: Intubation possible when aided by a stylet
Grd 4: Failed intubation

34. TRACHEA
*Starts from cricoid ring(c6) to carina(t5)
*Length 10-16 cm
*Consists of 16-20 incomplete rings
*External diameter of trachea
Male: 2.3cm coronally
1.8cm sagitally
Female:2cm coronally
1.4cm sagitally
*Internal diameter 1.2 cm
*It s flattened posteriorly and contains 16-20 horse shoe shaped cartilaginous
rings
*The post.part of trachea void of cartilage,consists of membrane of smooth muscle
and fibro elastic tissue joining the ends of cartilage.

35. *The rings are incomplete to allow the trachea to collapse
slightly so that food can pass down the oesophagus.
*At the 6th ring trachea becomes intrathoracic
*Divided into rt and lt main bronchus at carina
*Distance from upper incisor to carina 28-30cm
*Trachea lined by pseudostratified ciliated columnar
epithelium.

36. 36
 Trachealis muscle can decrease diameter of trachea
 Esophagus can expand when food swallowed
 Food can be forcibly expelled
 Wall of trachea has layers common to many tubular organs –
filters, warms and moistens incoming air
 Mucous membrane (pseudostratified epithelium with cilia and lamina
propria with sheet of elastin)
 Submucosa ( with seromucous glands)
 Adventitia - connective tissue which contains the tracheal cartilages)

37. 37

38. 38
Carina*
 Ridge on
internal
aspect of last
tracheal
cartilage
 Point where
trachea
branches
(when alive
and standing
is at T5)
 Mucosa highly
sensitive to
irritants:
cough reflex
*

39. VARIOUS MEAN DISTANCES IN ADULTS OF INTEREST TO THE
ANAESTHESIOLOGIST:
1.Mean distance from lips to carina:
male 35.2cm
female 28.5cm
2.Mean distance from nose to carina:
male 31cm
female 28.4cm
3.Mean distance from lips to vocal cords:
male 12-16cm
female 10-14cm
4.Mean distance from upper edge of larynx to lower edge of cricoid:
4-6cm
5.Mean length of trachea (vocal cord to carina):
Male 12-14cm
Female 10-12cm

40. *Dichotomous division starting with tachea and ending in alveolar
sac.

41. 41
 Bronchial tree bifurcation
 Right main bronchus (more susceptible to
aspiration)
 Left main bronchus
 Each main or primary bronchus runs into hilum of
lung posterior to pulmonary vessels
1. Oblique fissure
2. Vertebral part
3. Hilum of lung
4. Cardiac impression
5. Diaphragmatic surface
(Wikipedia)

42. RIGHT MAIN BRONCHUS LEFT MAIN BRONCHUS
1.Shorter(2.5cm) 1.Longer(5cm in man,4.5cm
in woman
2.Wider 2.Narrower
3.Angle with vertical 25 degree 3.Angle is 45 degree
4.Aorta arches over the
left main bronchus

43. APPLIED ANATOMY:
1.Due to shorter wider and less acute angle, chances of endotracheal tube to
be positioned on rt side are more.
2.Foreign body aspiration:
The right main stem bronchus is wider shorter and vertically placed and
therefore the posterior segment of rt. Upper lobe is anatomicall most
susceptible to aspiration pneumonia.
*Segments involved aspiration in supine position:
>Rt. Upper lobe-post.segment(mostly)
>Rt. lower lobe – superior segment
>Lt. lower lobe – superior segment
* Segments involved aspiration in sitting or errect position:
>Basilar segments of rt. Lower lobe
>Basilar segments of lt. lower lobe

44. 44
 Main=primary bronchi divide into
secondary=lobar bronchi, each supplies
one lobe
 3 on the right
 2 on the left
 Lobar bronchi branch into tertiary =
segmental bronchi
 Segmental bronchi further divide and redivide till terminal
bronchiole.
 Tubes smaller than 1 mm called bronchioles
 Smallest, terminal bronchioles, are less the 0.5 mm diameter
 Terminal bronchioles loose their cartilage to form respiratory bronchiole.
 Lining-pseudostratified ciliated columnar epithelium up to terminal
bronchioles after which non ciliated epithelium.
 Terminal bronchiole lined by nonciliated columnar epithelium
 Respiratory bronchiole lined by cuboidal cells
 Alveoli are lined by squamous cells.

45. Segmental bronchi:

46. Broncho pulmonary segments:
*Broncho pulmonary segments are independent respiratory units.
*Each segment has its own separate artery and each segment has
more than one vein.
*Bronchopulmonary segment is not a bronchovascular segment
because it dose not have its own vein.
APPLIED ANATOMY:
Usually the infection of segment remains restricted to it,although some
inections like TB may spread from one segment to another

47. 47
Respiratory Zone
 End-point of respiratory tree which
take part in gas exchange
 Structures that contain air-
exchange chambers are called
alveoli
 Respiratory bronchioles lead into
alveolar ducts.
 Ducts lead into terminal clusters
called alveolar sacs – are
microscopic chambers
 Each alveolar sac contains avg.17
alveoli

48. ALVEOLI
*About 300 million alveoli provide an enormous membrane(50-100m2) for
gas exchange in an avg.adult.
*Alveolar size depends on both gravity and lung volume.
*The avg. diameter 0.05-0.33mm.
*In upright position largest alveoli are at the pul.apex and smallest at base.
*Each alveolus is in close contact with a network of pulmonary capillaries.
*The walls of alveolus are asymmetrically arranged.
*On the thin side(0.4micro.m) where gas exchange occurs,the alveolar epithelium
and capillary endothelium are separated by their respective cellular and
basement membranes.
*On the thick side(1-2micro.m), where fluid and solute exchange occurs through
the pulmonary interstitial space.
*The alveolar epithelium contains two types of cells:
1.Type 1 pneumocytes:Form tight junctions with one another which
prevent the passage of oncotically active molecules such as
albumin in to alveolus.

50. 2.Type 2 pneumocytes:
> Produce surfactant which prevents the alveoli from collapsing
by reducing surface tension.
> Unlike type1 cells,these cells are capable of cell division and
can produce type 1 cells if the later are destroyed.
> They are also resistant to oxygen toxicity.
CLINICAL IMPORTANCE: In absence of surfactant as in premature babies
devlop respiratory distress syndrome.

51. Artery supply of bronchial tree:
> Upto terminal bronchioles – bronchial artery
>Beyond the terminal bronchioles-pulmonary
artery
Nerve supply of bronchial tree:
>Parasympathetic by vagus(bronchoconstriction)
>Sympathetic(T2-T5) (bronchodilatation)

52. MUSCLES OF RESPIRATION:
*During quite inspiration: *During forced inspiration:
>Diaphragm(main) >Sternocleidomastoid
>External intercostal >Seratous anterior
>Inter chondral portion of >Scaleni
the internal intercostals >Erector spinae
>Alaque nasi
>Pectoralis major and minor

53. *During quite expiration: *During forced expiration:
>Elastic recoil of alveoli and >Abdominal muscles
thoracic wall >Latissimus dorsi
>Internal intercostal
>Transverse thoracic
APPLIED ANATOMY:
During anaesthesia with inhalational agents, expiration is
active,mediated by abdominal muscles.

54. LUNGS AND
PLEURA

55. PLEURA
*Two types of pleura found in lung :Visceral pleura
Parietal pleura
*Visceral pleura:
>It covers the surfaces and fissures of lung except at hilum.
>Along the attachment of pulmonary ligament it is continuous with parietal
pleura.
>It is firmly adherent to lung and cannot be separated from it.
>It is pain insensitive.
*Parietal pleura:
>It is thicker than visceral pleura.
>Subdivided in to four parts:
1.Costal
2.Diaphragmatic
3.Mediastinal
4.Cervical

56. >There are two folds or recess of parietal pleura which act as reserve
spaces for the lung to expand during deep inspiration,ie.costomediastinal recess
and costodiaphragmatic recess.
>Parietal pleura is pain sensitive.
*In between two pleura pleural cavity present,
which contains abt. 30-50 ml of fluid normally.
*Nerve supply:
Parietal pleura-Somatic nerve(intercostal
and phrenic nerve)
Visceral pleura-Autonomic nerves
*blood supply:
>Parietal pleura-
Art.supply : Intercostal,internal thoracic,
musculophrenic arteries
Vein drainage: Azygos,internal thoracic vein
>Visceral pleura-
Art.supply: Bronchial arteries
Vein drainage: Bronchial veins

57. LUNGS
*Right lung weighs about 700 gm.
*It is about 50-100 gm heavier than the left lung.
*The rt lung is divided in to three lobes(upper,middle,lower) by two fissures,
ie.oblique or major and horizontal or minor fissure
*Left lung divided in to two lobes by oblique fissure
*Surface marking:
>Upper border of lung-limited up to 6cm above sternoclavicular joint.
>Lower border of lung-lies on 6th rib,8th rib,10th rib on the
midclavicular,midaxillary,post.scapular line respectedly.
>Oblique fissure-starts from T2 posteriorly and extends obliquely
downwards and forwards to the 6th costochondral junction anteriorly.
>Horizontal fissure-starts from the rt 4th costochondral junction and passes horizontaly to
meet oblique fissure in the mid axillary line.

59. Root of lung:
>It connects the medial surface of the lung to the mediastinum.
>Roots of the lungs lies opposite the bodies of T5-T7.
>Contents:
1.Principal bronchus on the left side and eparterial,hyparterial
bronchi on the right side
2.One pulmonary artery
3.Two pulmonary veins
4.Bronchial arteries,
one on the rt side and
two on left side
5.Bronchial vein
6.Lymphatics of lung
7.Broncho pulmonary
lymh nodes
8.Areolar tissue

60. Differences between right and left lung
Right lung Left lung
1.It has 2 fissures and 3 lobes. 1.It has one fissure and 2 lobes.
2.Anterior border is straight. 2.Ant.border is interrupted by
the cardiac notch.
3.Larger and heavier 3.Smaller and lighter
4.Shorter and broader 4.Longer and narrower

61. COMPARISION BETWEEN PEDIATRIC & ADULT AIRWAY
1– Relatively larger tongue – Obligate nasal
breather.
2 – Large & omega-shaped epiglottis
3 –In children the angle of both rt. And
lt.bronchus is same,ie;55 degree upto the
age of 3 yrs.
4 - Narrowest part of pediatric airway is
cricoids cartilage or subglottis up to the
age of 5 yrs..
5 – Angled vocal cord – Infant VC have more
angled attachment to thyroid angle
whereas adult VC are more perpendicular.

62. CHEST XRAY(NORMAL)

63. PLEURAL EFFUSION

64. EMPHYSEMA

65. PNEUMOTHORAX

66. CONSOLIDATION(PNEUMONIA)

67. HYDROPNEUMOTHORAX

68. BRONCHIECTASIS

69. REFERENCES:
 Benumof’s Airway Management (3rd edition)
 Miller’s Anesthesia (7th edition)
 Morgan Clinical Anesthesiology (5th edition )
 Rashid M Khan airway management(4th edition)
 Ajay Yadav text book of anaesthesia(4th edition)
 B D Chaurasia human anatomy
 Grays anatomy
 E-books

70. THANK YOU