Trachea, bronchial tree and lungs Flashcards
structure of the trachea
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
what lies at the posterior aspect of the trachea
Trachealis muscle (posteriorly, between the ends of the tracheal cartilages) alters tracheal diameter
relation to the left recurrent laryngeal nerve
nerve lies in the groove between the trachea and the oesophagus
arterial supply of the trachea
Inferior thyroid artery Bronchial arteries Tracheal branches of aorta Mediastinal branches of internal thoracic artery
venous supply of the trachea
Inferior thyroid vein (plexus)
Bronchial veins
lymph supply of the trachea
Pretracheal lymph nodes
Paratracheal lymph nodes
nervous supply of the trachea
Parasympathetics: Vagus
Sympathetics: Sympathetic
trunks
what is the significance of the right main bronchus
Right main bronchus is slightly more vertical, shorter and wider
so more susceptible to foreign body aspiration
The divisions of the trachea
- 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
BRONCHIOLES
these cause the greatest resistance to air flow in the conducting passages
PULMONARY ALVEOLI
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
what are the three surfaces of the lungs
Costal, Diaphragmatic, Mediastinal
what are the three margins of the lungs
Anterior, posterior, inferior
what is the structural difference between the right and left lung
– 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
what separates the lobes
– Oblique fissure
– Horizontal fissure (only in the right lung)
what is the contents of the root of the lung
− 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
what is the rough structure of the hilum of the lung
the bronchi lie posteriorly and the pulmonary arteries lie superiorly and the pulmonary veins lie inferiorly anteriorly
BRONCHOPULMONARY SEGMENTS
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
tell me about the veins and lymphatics in the bronchopulmonary segments
Tributaries of the pulmonary vein and lymphatics tend to pass in the inter-segmental septum
HISTOLOGICAL FEATURES of bronchioles
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
Type I alveolar cell
permit diffusion
Type II alveolar cell
Produce Surfactant that reduces the tendency for pulmonary alveoli to collapse.
which segment is prone to pneumonia
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
BRONCHOGRAM
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.