Trachea, Bronchial Tree and Lungs Flashcards
(32 cards)
Where does the trachea run from?
C6 to T4/5 at the carina
What makes up the trachea?
- C shaped hyaline cartilages (keep lumen patent)
- trachealis muscle: posteriorly between ends of tracheal cartilages (alters tracheal diameter)
What are the relations of the trachea?
- sternohyoid muscle
- stermothyroid muscle
- isthmus of the thyroid gland
- inferior thyroid vessels
- carotid sheath
- brachiocephalic trunk
- jugular venous arch
- recurrent laryngeal nerve
Describe how the trachea enters the thoracic cavity
- enters through the thoracic inlet
- divides into left and right principal bronchi
Where does the left recurrent laryngeal nerve sit?
in the groove between the trachea and oesophagus
What arteries supply the trachea?
- inferior thyroid artery
- bronchial arteries
- tracheal branches of aorta
- mediastinal branches of ITA
What veins drain the trachea?
- inferior thyroid vein
- bronchial veins
What nerves supply the trachea?
- parasympathetics: vagus
- sympathetic trunks
What lymph nodes drain the trachea?
- pretracheal lymph nodes
- paratracheal lymph nodes
Describe the morphology of the principal bronchi and the clinical relevance of this
- right principal bronchi is more vertical, shorter and wider
- more likely for foreign body to enter right principal bronchi
What does the main bronchi divide into?
- lobar bronchi that subdivides into segmental bronchi
- segmental bronchus passes to a broncho-pulmonary segment
What do segmental bronchi lead to?
- terminal bronchioles
- connected to respiratory bronchioles
- bronchioles cause the greatest resistance to air flow in conducting passages
What do bronchioles lead to?
- connected to alveolar ducts
- ducts open into alveolar sacs which are clusters of pulmonary alveoli
- provides a very large surface area for diffusion of gases
What are the surfaces and margins of the lungs?
Surfaces:
- costal
- diaphragmatic
- mediastinal
Margins:
- anterior
- posterior
- inferior
What are the differences in shape between the right and left lung?
Right:
- 3 lobes separated by an oblique and horizontal fissure
- shorter but wider
Left:
- 2 lobes separated by an oblique fissure
- has a cardiac notch
What are the impressions for on the right lung?
- oesophagus
- SVC
- right atrium
- IVC
- pulmonary ligament
What are the impression for on the left lung?
- subclavian artery
- aortic arch
- left ventricle
- pulmonary ligament
Where does the vagus nerve pass the lungs?
posterior to the lung roots
What vessels are in the root of the lung?
- a pulmonary artery
- 2 pulmonary veins
- a main bronchus
- bronchial vessels
- nerves
- lymphatics
Describe the arrangement of the vessels in the root of the lungs
- main bronchi sit most posteriorly
- pulmonary arteries superior
- pulmonary veins inferior
What are the bronchopulmonary segments?
- sections of the lung with its own branch of pulmonary artery, nerves and segmental bronchus
- pyramid shaped with apices directed towards hilum
- separated by connective tissue
- no anastomosis between segments
Describe the divisions of the bronchopulmonary segments
- 10 segments on each side
- upper lobe: apical, anterior and posterior
- middle/lingula: medial and lateral
- lower lobe: apical, medial, lateral, anterior and posterior
Describe the histological features of the lungs
- little cartilage in bronchioles, mainly smooth muscle
- no goblet cells in and distal to bronchioles
- pseudostratified columnar epithelium in bronchi replaced by simple cuboidal epithelium in bronchioles
- wall of pulmonary alevoli one cell thick (for diffusion)
Type I and II alveolar cell
- type I: permit diffusion
- type II: produce surfactant (lowers tension) that reduces tendency for pulmonary alveoli to collapse
