Presentation on anatomy of respiratory system. For anesthesia residents seminar presentation

1. Anatomy of the
Respiratory system
Presented by Dr Niyas Usman
Guided by Dr Deepak Choudhary

2. Divisions of the Respiratory
system
 Mouth
 Nose and Nasal cavity
 Pharynx
 Larynx
 Trachea and Bronchial tree
 Lungs and pleural membranes
 Alveoli

4. MOUTH
The palate:
 The hard palate is made up of the palatine processes
of the maxillary and the horizontal plates of the
palatine bones.
 The soft palate hangs like a curtain suspended from
the posterior edge of the hard palate. It's free border
bears the uvula centrally and blends on either side
with the pharyngeal wall.
 Palatine aponeurosis: tough fibrous sheet, the
'skeleton' of the soft palate.

5. Mallampatti Score
 Class 1. Complete visualization of the soft palate
 Class 2. Complete visualization of the uvula
 Class 3. Visualization of only the base of the uvula
 Class 4. Soft palate is not visible at all

7. NOSE
Nasal cavity
 Subdivided by the nasal septum into two quite
separate compartments
 It opens to the exterior by the nares and into the
nasopharynx by the posterior nasal apertures or
choanae.
 Immediately within the nares is a small dilatation, the
vestibule, which is lined in its lower part by stiff,
straight hairs

9. NASAL INTUBATION

11. NASAL INTUBATION
CAUTIONS
 Occasionally, the posterior end of the inferior turbinate
may be hypertrophied--- resistance
 The delicate mucosa of the nose and the posterior
pharyngeal wall may easily be torn, and force must
never be used in this manoeuvre
 Cases are on record of nasal tubes being passed
through the mucosa of the posterior pharyngeal wall
into the retropharyngeal space and of serious
haemorrhage from injury to the posterior ethmoidal
vessels, which are branches of the internal carotid
artery via the ophthalmic artery and therefore
impossible to control by proximal ligation.

12. PHARYNX
 Nasopharynx
 Oropharynx
 Laryngopharynx

13. Nasopharynx
 Passage for air only
 Soft palate is elevated during swallowing
to prevent food or saliva from going into
the nasopharynx
 In the lateral wall of nasopharynx, paired
eustachian tubes connect the nasopharynx
to middle ear.
 Posterior pharyngeal wall houses a single
pharyngeal tonsil, commonly called the
adenoids.

14. Oropharynx
 Arch like entranceway- fauces
 From soft palate to the tip of the epiglottis
 Two types of tonsils
-- Palatine tonsils -- In the lateral walls of the
fauces
-- Lingual tonsils -- covers the posterior surface of
the tongue

15. Waldeyer's Ring
 It is a ring of lymphoid tissue in the human pharynx. It
consists of several groups of lymphoid tissue :
 Pharyngeal tonsils
 Tubal tonsils
 Palatine tonsils
 Lingual tonsil
 Waldeyer's ring acts as a protective ring of immune
tissue, helping to defend against pathogens that
enter the body through the nose and mouth.

16. Ludwig's Angina
 It is a serious and potentially life-threatening
bacterial infection that occurs in the floor of the
mouth, under the tongue.
 The spread of edema is restricted by the pharyngeal
fascia to the tissues of the larynx and pharynx.
 Difficulty in swallowing to laryngeal obstruction
 Life threatening if not realised early and surgical
drainage of deep pharyngeal tissues not performed.
 Anaesthetist should consider advisability of
tracheostomy in these patients.

17. Laryngopharynx
 From tip of epiglottis to the lower border of the
cricoid at the level of C6
 Permits passage of both food and air
 Piriform fossa : The larynx bulges back into the centre
of the laryngopharynx, leaving a recess on either side.
 Here swallowed sharp foreign bodies such as fish
bones tend to impact.

19. Piriform Fossa Implications
 The internal branch of the superior laryngeal nerve
passes in the submucosa of the piriform fossa.
 Local anaesthetic solutions applied to the surface of the
piriform fossa on wool balls held in Krause's forceps will
produce anaesthesia of the larynx above the vocal cords
 It is a useful nerve block to supplement oral anaesthesia
for laryngoscopy.

20. Muscles of the Pharynx
 Superior, middle and inferior constrictor muscles -
fibers run in a somewhat circular direction.
 Cricopharyngeus muscle - lower part of the inferior
constrictor, which arises from the cricoid cartilage.
 Stylopharyngeus and Salpingopharyngeus muscles -
fibers run in a somewhat longitudinal direction.

22. Nerve Supply of Pharynx
 All muscles except Stylopharyngeus - Pharyngeal
plexus
 Stylopharyngeus - Glossopharyngeal nerve
 Sensory nerve supply of Pharyngeal mucous
membrane:
Nasal Pharynx: The maxillary nerve (V2)
Oral Pharynx: The glossopharyngeal nerve
Laryngeal Pharynx: The internal laryngeal branch of
the vagus nerve.

23. Importance
 Before larynx it is the pharynx which makes the
main airway; hence it has to be managed first.
 Helps in deglutition, protects larynx from
aspiration.

26. LARYNX
 Voice box is a short, somewhat cylindrical airway
which ends in trachea.
 It prevents the swallowed materials from entering
the lower respiratory tract.
 Conducts air into the lower respiratory tract.
 Produces sounds
 Supported by a framework of nine pieces of cartilage
( 3 individual and 3 pairs) that are held in place by
ligaments and muscles.

27. Cartilages of Larynx
 Thyroid cartilage - single, Adam's apple, hyaline
cartilage, anterior attachment of vocal folds,
testosterone increases size after puberty.
 Cricoid cartilage - single, ring shaped,, hyaline cartilage.
 Arytenoid cartilage - paired, hyaline cartilage, posterior
attachment of vocal folds.
 Cuneiform cartilage - paired, hyaline cartilage.
 Corniculate cartilage - paired, hyaline cartlage.
 Epiglottis - single, elastic cartilage.

29. Larynx
 Muscular walls aids in noise production and the
swallowing reflex
 Glottis - the superior opening of the larynx
 Epiglottis - prevents food and drink from entering the
airway when swallowing.

30. Vocal Cords
 Inferior ligaments are called the vocal cords.
 True Vocal cords - produce sound when air passes
through them
 Superior ligaments are called the vestibular folds
 False Vocal cords - no function in sound production,
protects the vocal folds
 The tension, length and position of the vocal folds
determine the quality of the sound

32. Larynx
 The cavity of the larynx extends from the inlet to
the lower border of cricoid cartilage, where it is
continuous with the cavity of trachea. It is divided
into 3 regions :
 The vestibule - which is situated between the inlet
and the vestibular folds
 The middle region which is situated between the
vestibular folds above and the vocal folds below
 The lower region which is situated between the
vocal fold above and the lower border of the
cricoid cartilage below.

33. Larynx
 Sinus of the larynx - it is a small recess on each side
of the larynx situated between the vestibular and
vocal folds
 It is lined with mucous membrane.
 Saccule of the larynx - it is a diverticulum of mucous
membrane that ascends from the sinus.
 The mucous secretion lubricated the vocal cords.

35. Muscles of the Larynx
 Extrinsic muscles
• Move the larynx up and down during swallowing
• Many of these Muscles are attached to the hyoid
bone, which is attached to the thyroid cartilage by the
thyrohyoid membrane.
• Movements of the hyoid bone are accompanied by the
movements of the larynx.
• Elevation - digastric, stylohyoid, mylohyoid,geniohyoid,
stylopharyngeus, Salpingopharyngeus and the
palatopharyngeus muscles.
• Depression - sternothyroid, sternohyoid and the
omohyoid muscles.

36. Muscles of the Larynx
 Intrinsic muscles
• Two muscles modify the laryngeal inlet.
• Narrowing the inlet: the oblique arytenoid muscle
• Widening the inlet: the thyroepiglottic muscle
• Five muscles move the vocal cords:
• Tensing : the cricothyroid muscle
• Relaxing : the thyroarytenoid (vocalis) muscle
• Adduction: the lateral cricoarytenoid muscle
• Abduction: the posterior cricoarytenoid muscle
• Approximates the arytenoid cartilages: the transverse
arytenoid muscle

37. Nerve supply of the Larynx
 Sensory nerves
• Above the vocal cords: the internal laryngeal branch of
the superior laryngeal branch of the vagus.
• Below the level of the vocal cords: the recurrent
laryngeal nerve
 Motor nerves
• All the intrinsic muscles of the larynx except the
cricothyroid muscle are supplied by the recurrent
laryngeal nerve.
• The cricothyroid muscle is supplied by the external
laryngeal branch of the superior laryngeal branch of
the vagus.

39. Blood supply of the Larynx
 Upper half of the larynx: The superior laryngeal
branch of the superior thyroid artery.
 Lower half of the larynx: The inferior laryngeal
branch of the inferior thyroid artery.

48. TRACHEA
 It is a flexible tube also called windpipe.
 It is about 11.25cm long and 2.5cm in diameter.
 Extends through the mediastinum and lies anterior
to the oesophagus and inferior to the larynx.
 Anterior and lateral walls of the trachea are
supported by 15 to 20 C shaped tracheal cartilages.
 Cartilage rings reinforce and provide rigidity to the
tracheal wall to ensure that the trachea remains
open at all times.
 Posterior part of trachea is lined by trachealis
muscle.

49.  At the level of the sternal angle, the trachea
bifurcates into smaller tubes, called the right
and left primary bronchi.
 Each primary bronchus projects laterally towards
each lung.
 The most inferior tracheal cartilage separates
the primary bronchi at their origin and forms an
internal ridge called the carina.
 The upper 2/3 is supplied by inferior thyroid
arteries.
 The lower 1/3 is supplied by Bronchial arteries.

51. Trachea
 Unilateral or bilateral enlargement of the thyroid
gland can cause gross displacement or compression
of the trachea.
 Dilatation of the aortic arch(aneurysm) can
compress the trachea.
 Inhaled foreign bodies---> Right lung

52. BRONCHIAL TREE
 Air conducting passages that originate from the left
and right primary bronchi.
 Progressively branch into narrower tubes before
terminating into terminal bronchioles.
 Incomplete rings of hyaline cartilage support the
walls of the primary bronchi to ensure that they
remain open.
 Right primary bronchus - shorter, wider and more
vertical.
 Foreign particles are more likely to lodge in the
right primary bronchus.

53.  The primary bronchi---> hilus of each lung together
with the pulmonary vessels, lymphatic vessels, and
nerves.
 Primary bronchus---> several secondary bronchi
 Left lung has two secondary bronchi.
 Right lung has three secondary bronchi
 They further divide into tertiary bronchi.
 Each tertiary bronchus is called a segmental
bronchus because it supplies a part of the lung
called a bronchopulmonary segment.

54. PRIMARY BRONCHI
Right bronchus
• Larger
• Leaves the trachea at
25°angle
• Divides into secondary
bronchi before entering
the lung
• 10 bronchopulmonary
segments
Left bronchus
• Departs the trachea at
45°angle
• Does not divide into
secondary bronchi until it
reaches the lung
• 8 bronchopulmonary
segments

55. LUNGS
 Cone shaped
 Total volume of 3.5 - 8.5 litres
 Superior portion is apex
 Inferior portion is base
 Apical portion rises above the clavicle
 Attached by hilum and pulmonary ligament

56. Lungs
Left lung
• Divided into 2 lobes by oblique fissure
• Smaller than the right lung
• Cardiac notch accomodates the heart
Right lung
• Divided into 3 lobes by oblique and horizontal
fissure
• Located more superiorly in the body due to liver
on the right side

57.  Bronchopulmonary segments are as follows :
 Right lung
• Superior lobe : Apical, posterior, anterior
• Middle lobe : Lateral, medial
• Inferior lobe : Superior (apical), medial basal,
anterior basal, lateral basal, posterior basal
 Left lung
• Superior lobe : Apicoposterior, anterior, superior
lingular, inferior lingular.
• Inferior lobe : Superior (apical), anteromedial
basal, lateral basal, posterior basal

62.  Pulmonary circulation
--- Pulmonary artery
• Carry blood to the lungs for oxygenation. These
vessels are central in each bronchopulmonary
segment and branch in a manner similar to the
segmental bronchi. They are considered segmental in
nature.
--- Pulmonary vein
• Present at the periphery of each segment and are
considered intersegmental.
 Bronchial artery (branches of descending aorta):
supply blood to the lungs. One for right lung and two
for left lung.

63. Nerves to Lung
 At the root of each lung is a pulmonary plexus
composed of efferent and afferent autonomic nerve
fibers. The plexus is formed from branches of the
sympathetic trunk and receives parasympathetic
fibres from the vagus nerve.
 Sympathetic efferent fibres--> bronchodilation and
vasoconstriction
 Parasympathetic efferent fibres-->
bronchoconstriction, vasodilation and increased
glandular secretion.

64. Ventilation of the Lungs
 Young children --> ribs are nearly horizontal --> rely
mainly on the descent of diaphragm to increase their
thoracic capacity on inspiration --> known as abdominal
type of respiration.
 After the second year of life, ribs become more oblique,
and adult form of respiration is established.
 In adults a sexual difference exists
 Females tend to rely mainly on the movements of the
ribs rather than on the descent of the diaphragm on
inspiration and is referred as thoracic type of respiration
 Males use both types but mainly the abdominal form.

65. Muscles Assisting
Ventilation
 The scalenes help increase thoracic cavity
dimensions by elevating the first and second ribs
during forced inhalation.
 The ribs elevate upon contraction of the external
intercostals, thereby increasing the transverse
dimensions of the thoracic cavity during inhalation.
 Contraction of the internal intercostals depressed
the ribs, but this only occurs during forced
exhalation
 Normal exhalation requires no active muscular
effort

68. PLEURA
 The outer surface of each lung and the adjacent
internal thoracic wall are lined by a serous membrane
called pleura.
 The outer surface of each lung is tightly covered by
the visceral pleura.
 While the internal thoracic walls, the lateral surfaces
of the mediastinum, and the superior surface of the
diaphragm are lined by the parietal pleura.
 The parietal and visceral pleural layers are continuous
at the hilus of each lung.

69. PLEURAL CAVITY
 The potential space between the serous membrane
layers is a pleural cavity.
 The pleural membranes produce a thin, serous
pleural fluid that circulates in the pleural cavity and
acts as a lubricant, ensuring minimal friction during
breathing.
 Pleural effusion -- pleuritis with too much fluid

72. ALVEOLI
 Structure: Alveoli are small, balloon-like structures
located at the end of the bronchioles in the lungs.
They resemble clusters of grapes and are surrounded
by a network of tiny blood vessels called capillaries.
 Each alveolus is lined by a single layer of epithelial
cells, known as alveolar epithelium. The alveolar
walls are extremely thin, allowing for efficient gas
exchange.
 The alveoli are coated with a surfactant, a lipoprotein
substance that reduces surface tension. Surfactant
prevents the alveoli from collapsing during exhalation
and helps maintain their stability.

73.  Adjacent to the alveolar walls are pulmonary
capillaries. These tiny blood vessels have thin walls
that facilitate the exchange of gases between the
alveoli and the bloodstream.
 The lungs have a rich blood supply to ensure efficient
exchange of gases. The network of capillaries around
the alveoli maximizes the surface area available for
gas exchange.
 The respiratory membrane is the thin barrier between
the alveolar air and the blood in the capillaries. It
consists of the alveolar epithelium, the capillary
endothelium, and their shared basement membrane.
This membrane allows for the diffusion of gases.

75. THANK YOU