7. Physiological Division
Conduction zone
◦ Consists of nasal cavity to terminal bronchioles
Respiratory zone
◦ Consists of alveoli, alveolar sacs, alveolar ducts and
respiratory bronchioles
11. The upper two thirds are supplied by the inferior thyroid
arteries
The lower third is supplied by the bronchial arteries
12. The lymph drains into the pretracheal and
paratracheal lymph nodes and the deep cervical
nodes
13. The sensory nerve supply is from the vagi and the
recurrent laryngeal nerves
Sympathetic nerves supply the trachealis muscle
14. The trachea bifurcates behind the arch of the aorta into
the right and left principal (Primary, or Main) bronchi
The bronchi divide into several million terminal
bronchioles that terminate in one or more respiratory
bronchioles
15.
16. • Right main bronchus
– Wider
– More vertical
– Shorter
– 20-30 degree angle
• Left main bronchus
– Narrower
– More angular
– Longer
– 40-60 degree angle
17.
18.
19.
20.
21. Alveoli
•The alveoli are the functional unit of the lungs.
•The bronchioles terminate in the ALVEOLI through an
ALVEOLAR DUCT.
•Walls of the alveoli are highly vascularized.
•The alveoli are the terminal branches of the BRONCHIAL
TREE. This arrangement allows for a drastic increase in
surface area.
22. Alveoli
•They have a thin wall specialized to promote diffusion of
gases between the alveolus and the blood in the
pulmonary capillaries.
•Gas exchange can take place in the respiratory
bronchioles and alveolar ducts as well as in the alveoli,
each lung contains approximately 300 to 400 million
alveoli.
•The spongy nature of the lung is due to the packing of
millions of alveoli together.
24. Type I
pneumocytes-large
flattened cells,
present a very thin
diffusion barrier for
gases
Type II
pneumocytes-
secretes
surfactant,which
decreases the
surface tension
between thin
alveolar walls
Type III
macrophages
27. ANGLEOFMAIN BRONCHI
25
45 45
45
A). B).
A: In Adults: Hence more chances of rt bronchial intubation
B :In Children (under the age of 3yrs the angulation of the two main bronchi at the
carina is equal on both sides.)
LEFTRIGHT
Rt Lt
29. CHANGE IN CARINA POSITION WITH FLEXION
AND EXTENSION
•Lengthening of the trachea during neck extension
occurs mainly between the vocal cords and the
sternal notch.
• ETTs fixed at the mouth ascend on average 2 cm in
the trachea with neck extension---- >chance of
accidental extubation
•During flexion, the tube moves toward the carina
or even the bronchus
30. RELATION B/W POSTURE AND LOCATION OF
LUNG ABCESS
Patient Lying On right Side:
inhaled materials collect in
posterior segment of right
upper lobe.
Patient lying on back:
inhaled materials collect in
apical segment of right
lower lobe.
31. Thoracic surgery
Lung isolation techniques:
• Double lumen tube
• Bronchial blocker
lung resection : Bronchopulmonary segments are
functionally and anatomically distinct from each other ----------------
----- > a segment of diseased lung can be removed surgically
without adversely affecting the rest of the lung
Well defined structure in the lung each one of which is aerated by Terminl bronchiole
Intersegmental Planes: Each segment surrounded by a connective tissue which is contious with pleura
Connective tissue adjoining each segments form the intersegmental planes which are crssed by pulmonar artery
Trachea begins in the neck as a continuation of the larynx at the lower border of the cricoid cartilage at the level of the sixth cervical vertebra
Extends from larynx to superior border of T5
In the thorax the trachea ends below at the carina by dividing into right and left principal (main) bronchi
In adults the trachea is about 4½ in. (11.25 cm) long and 1 in. (2.5 cm) in diameter
The fibroelastic tube is kept patent by the presence of U-shaped rings of hyaline cartilage embedded in its wall
The posterior free ends of the cartilage are connected by smooth muscle, the trachealis muscle
In the neck (Fig. 37), it is covered anteriorly by the skin and by the super- ficial and deep fascia, through which the rings are easily felt. The 2nd to the 4th rings are covered by the isthmus of the thyroid where, along the upper border, branches of the superior thyroid artery join from either side. In the lower part of the neck, the edges of the sternohyoid and sternothy- roid muscles overlap the trachea, which here is also covered by the inferior thyroid veins (as they stream downwards to the brachiocephalic veins), by the cross-communication between the anterior jugular veins and, when present, by the thyroidea ima artery, which ascends from the arch of the aorta or from the brachiocephalic artery. It is because of this close relation- ship with the brachiocephalic artery that erosion of the tracheal wall by a tracheostomy tube may cause sudden profuse haemorrhage. It is less com- mon for the carotid artery to be involved in this way. On either side are the lateral lobes of the thyroid gland, which intervene between the trachea and the carotid sheath and its contents (the common carotid artery, the internal jugular vein and the vagus nerve). Posteriorly, the trachea rests on the oesophagus, with the recurrent laryngeal nerves lying on either side in
a groove between the two.
This “air-blood barrier” (the respiratory membrane) is where gas exchange occurs
Oxygen diffuses from air in alveolus (singular of alveoli) to blood in capillary
Carbon dioxide diffuses from the blood in the capillary into the air in the alveolus
During flexion, the tube moves toward the carina or even the bronchus, depending on the original tube position and the extent of flexion. This is true in both adults and children. It is therefore necessary to exercise constant vigil when the neck is moved in any direction to rule out displacement of the tube tip.
