Trachea, bronchial tree and lungs

Question 1

structure of the trachea

Answer 1

 10-11 cm long, average 2,5 cm wide
 Starts at C6, ends at T4/5 at carina

 Composed of C-shaped hyaline cartilages
– Keep the lumen patent

Question 2

what lies at the posterior aspect of the trachea

Answer 2

 Trachealis muscle (posteriorly, between the ends of the tracheal cartilages) alters tracheal diameter

Question 3

relation to the left recurrent laryngeal nerve

Answer 3

nerve lies in the groove between the trachea and the oesophagus

Question 4

arterial supply of the trachea

Answer 4

 Inferior thyroid artery
 Bronchial arteries
 Tracheal branches of aorta
 Mediastinal branches of
internal thoracic artery

Question 5

venous supply of the trachea

Answer 5

 Inferior thyroid vein (plexus)

 Bronchial veins

Question 6

lymph supply of the trachea

Answer 6

 Pretracheal lymph nodes

 Paratracheal lymph nodes

Question 7

nervous supply of the trachea

Answer 7

 Parasympathetics: Vagus
 Sympathetics: Sympathetic
trunks

Question 8

what is the significance of the right main bronchus

Answer 8

Right main bronchus is slightly more vertical, shorter and wider
so more susceptible to foreign body aspiration

Question 9

The divisions of the trachea

Answer 9

• become right and left main bronchi at t4/t5
• then divide into lobar bronchi
• then into segmental bronchi
• these then pass into a broncho-pulmonary segment
• then divide into terminal bronchioles
  t
• these connect to respiratory bronchiloles

Question 10

BRONCHIOLES

Answer 10

these cause the greatest resistance to air flow in the conducting passages

Question 11

PULMONARY ALVEOLI

Answer 11

 Each respiratory bronchiole is connected to ~2 -11 alveolar ducts
 The alveolar ducts open into alveolar sacs, clusters of pulmonary
alveoli.
− Each alveolar duct is connected to ~5-6 alveoli
− Provides a very large surface area for the diffusion of gases

Question 12

what are the three surfaces of the lungs

Answer 12

Costal, Diaphragmatic, Mediastinal

Question 13

what are the three margins of the lungs

Answer 13

Anterior, posterior, inferior

Question 14

what is the structural difference between the right and left lung

Answer 14

– Left lung has cardiac notch
– Right lung is shorter but wider

there is also three lobes in the right lung and two lobes in the left lung

Question 15

what separates the lobes

Answer 15

– Oblique fissure

– Horizontal fissure (only in the right lung)

Question 16

what is the contents of the root of the lung

Answer 16

− A pulmonary artery
− Two pulmonary veins 
− A main bronchus
− Bronchial vessels
− Nerves
− Lymphatics
Covered by a sleeve of mediastinal pleura that reflects onto the surface of the lung

Question 17

what is the rough structure of the hilum of the lung

Answer 17

the bronchi lie posteriorly and the pulmonary arteries lie superiorly and the pulmonary veins lie inferiorly anteriorly

Question 18

BRONCHOPULMONARY SEGMENTS

Answer 18

Section of lung with its own branch of pulmonary artery, nerves
and segmental (tertiary) bronchus

NO ANASTOMOSIS BETWEEN SEGMENTS
therefore safe from the spread of disease e

Question 19

tell me about the veins and lymphatics in the bronchopulmonary segments

Answer 19

Tributaries of the pulmonary vein and lymphatics tend to pass in the inter-segmental septum

Question 20

HISTOLOGICAL FEATURES of bronchioles

Answer 20

 There is little cartilage in the bronchioles, mainly smooth muscle
 No goblet cells in and distal to respiratory bronchioles
 The pseudostratified columnar epithelium of the bronchi is replaced by simple cuboidal epithelium of the bronchioles

Question 21

 Type I alveolar cell

Answer 21

permit diffusion

Question 22

Type II alveolar cell

Answer 22

Produce Surfactant that reduces the tendency for pulmonary alveoli to collapse.

Question 23

which segment is prone to pneumonia

Answer 23

The apical segment of the inferior lobe is inferolateral to the upper, posterior position of the oblique fissure. As its tertiary bronchus drops off the bronchial tree posteriorly

Question 24

BRONCHOGRAM

Answer 24

phenomenon of air-filled bronchi (dark) being made visible by the opacification of surrounding alveoli (grey/white). It is almost always caused by a pathologic airspace/alveolar process, in which something other than air fills the alveoli.

Question 25

vascular supply of the lung tissue

Answer 25

bronchial arteries:
x1 on the right, from 3rd posterior intercostal artery or superior posterior intercostal artery
- x2 on the left, from the aorta
these can anatomise with he pulmonary arteries in the walls of the bronchioles

Question 26

where is the venous blood of the lung tissue drained by

Answer 26

Bronchial veins (into the azygos system) or by the pulmonary veins

Question 27

position the pulmonary arteries

Answer 27

• Right PA passes anterior to the right primary bronchus and posterior to the ascending aorta and SVC
• Left PA is shorter

Question 28

lymph drainage of the lung tissue

Answer 28

deep (running alongside the arteries and dividing bronchial tree) and superficial (sub-pleural) lymphatic plexuses

these both drain to the pulmonary lymph nodes which are buried in the hilum

Question 29

lymph travel from the pulmonary lymph nodes

Answer 29

• pulmonary nodes
• bronchiopulmonary nodes (around the man bronchi)
• inferior and superior tracheobronchial nodes
• paratracheal nodes
  • Left bronchomediastinal
  trunk
  • Right bronchomediastinal trunk
  • Thoracic duct
  • Right lymphatic duct

Question 30

nerve supply of the trachea

Answer 30

supplied by the pulmonary plexuses around the main bronchi at the root of the lung

Question 31

– Parasympathetic fibres

Answer 31

• From the vagus
• Synapse in the plexuses
• Postganglionic fibres resulting in bronchoconstrictor, vasodilator and secretomotor.

Question 32

– Sympathetic fibres

Answer 32

• From sympathetic trunk
• Synapse in the sympathetic ganglia
• Postganglionic fibres
resulting in bronchodilator, vasoconstrictor