Thorax 2 - Tracheobronchial tree Flashcards
(trachea, bronchi, bronchioles)
what are the contents of the tracheobronchial tree in order (from the trachea to alveoli)?
trachea
primary/main bronchi
secondary bronchi
tertiary bronchi
terminal bronchioles
respiratory bronchioles
acinus - clusters of alveoli
alveoli sacs - lined with ducts
what does the branching of bronchi into bronchioles allow for?
allows for more precise control of airflow and distribution of air throughout the lungs
the respiratory system consists of a CONDUCTING part & RESPIRATORY part - what does each part do?
conducting part = conducts air from the outside into the lungs
respiratory part = where gas exchange occurs (in the alveoli with the bloodstream)
where does the trachea start and end - vertebral levels?
originates at the lower border of the cricoid cartilage - C6/7
ends at the carina - T4/5
what is the carina?
a cartilaginous ridge at the level of T4/5 - marks the end of the trachea & bifurcation into the right and left main bronchi
what happens at the carina?
trachea ends & bifurcates into the right and left main bronchi
what is the shape of the hyaline cartilage rings in the trachea?
hyaline cartilage rings are C-shaped with an open posterior portion (covered by trachealis smooth muscle)
why is the posterior portion of the tracheal cartilage rings open?
prevents pressure on the oesophagus which lies immediately posterior to the trachea
why is the C-shape of the tracheal hyaline cartilage rings important?
- prevents compressing oesophagus posteriorly
- maintains patency/ prevents tracheal collapse
- allows flexibility of trachea -sympathetic innervation to the trachealis muscle can control trachea’s diameter
what fills the open posterior portion of the tracheal cartilage rings?
smooth muscle called the trachealis muscle
what is the purpose of the trachealis muscle?
- allows flexibility
- prevents compression of the oesophagus
- adjusts the tracheal diameter during coughing/ forced expiration
how does the right main bronchus differ from the left main bronchus in terms of structure?
right main bronchus is wider, shorter & more vertical
left main bronchus is narrower, more horizontal & appears more as a branching structure
why are foreign objects more likely to enter the right main bronchus in adults?
right main bronchus is wider, shorter & more vertical - more of a direct continuation of the trachea
more prone to foreign objects entering
what are the characteristics of an abnormal carina during bronchoscopy? what can this indicate?
blunted/ widened with underlying bumps - can indicate metastatic cancer spread to the inferior tracheobronchial lymph nodes
a widened and distorted carina with underlying bumps indicates problems with WHAT lymph nodes
inferior tracheobronchial LNs
in children, how do foreign objects tend to distribute between the right and left bronchi compared to adults?
in children = tend to distribute equally between both bronchi
in adults = more likely to enter the right main bronchus
what are the secondary bronchi? how do they differ between the right & left lungs?
secondary bronchi - branches of the primary/main bronchi
right lung has 3 secondary bronchi (corresponding to its 3 lobes)
left lung has 2 secondary bronchi (corresponding to its 2 lobes)
how many tertiary bronchi are there per lung? what is their function?
right lung - approx. 10
left lung - approx. 8-10
ensure efficient airflow to all parts of the lungs
what structural change occurs in the walls of terminal bronchioles compared to earlier bronchi?
terminal bronchioles no longer have hyaline cartilage in their walls - makes them more susceptible to collapse
role of respiratory bronchioles in the bronchial tree?
lead to the respiratory portion of the lungs and terminate in clusters of alveoli (acinus) - facilitate gas exchange.
what is the primary function of alveoli in the respiratory system?
alveoli are the sites of gas exchange (O₂ and CO₂) during breathing - maximise surface area for efficient gas exchange between air & blood
what happens to the structure of the bronchial tree as it progresses from tertiary bronchi to terminal bronchioles?
airways become smaller & hyaline cartilage isn’t present in the walls - makes them more susceptible to collapse
what arteries supply the upper two-thirds of the trachea? where do they arise from?
inferior thyroid arteries - branch from the subclavian artery
what arteries supply the lower one-third of the trachea? where do they arise from?
bronchial arteries - branches of the thoracic aorta (sometimes arise from the internal thoracic artery instead)
what is an anatomical variation in the origin of the bronchial artery?
the bronchial artery may arise from the internal thoracic artery instead of the thoracic aorta
which lymph nodes are involved in the lymphatic drainage of the tracheobronchial tree? (3)
pretracheal LNs
paratracheal LNs
deep cervical LNs
what nerves provide sensory innervation to the trachea?
the vagus nerve & recurrent laryngeal nerve (a branch of the vagus nerve)
what cranial nerve number is the vagus nerve?
10
what is the motor nerve supply to the trachealis muscle? what is its function?
supplied by sympathetic nerves - regulate tracheal diameter
how is the upper 2/3 of the trachea drained?
upper 2/3 is drained by inferior thyroid veins - to the superior vena cava
what is the venous drainage pathway for the lower two-thirds of the trachea and bronchial tree on the RIGHT side?
bronchial veins > azygos vein > superior vena cava
what is the venous drainage pathway for the lower two-thirds of the trachea and bronchial tree on the LEFT side?
bronchial veins > accessory hemiazygos vein > hemiazygos vein > crosses midline & into azygos vein > superior vena cava
what is the significance of the recurrent laryngeal nerve in tracheal innervation?
it’s a branch of the vagus nerve - provides sensory innervation to the trachea
how does the venous drainage of the trachea and bronchial tree reflect its arterial supply?
venous drainage follows a similar pattern to the arterial supply:
upper 2/3s of the trachea are supplied by the inferior thyroid arteries & drained by the inferior thyroid veins
lower 1/3 of the trachea is supplied by the bronchial arteries & drained by the bronchial veins - differing venous drainage on the left and right sides
how does venous drainage of the lower 1/3 of the trachea differ between the left & right sides?
left side: bronchial veins > accessory hemiazygos vein > hemiazygos vein > azygos vein > superior vena cava
right side: bronchial vein > azygos vein > superior vena cava
at which vertebral level does the trachea terminate and the carina begin?
A. T2/T3
B. T4/T5
C. T6/T7
D. T8/T9
B: T4/5
which of the following is true about the right main bronchus compared to the left?
A. It is narrower and more horizontal.
B. It is wider, shorter, and more vertical.
C. It is longer and less vertical.
D. It is less likely to be obstructed by foreign objects.
B: it’s wider, shorter, and more vertical (more likely to be obstructed by foreign objects)
which arteries supply the lower one-third of the trachea?
A. Bronchial arteries
B. Internal thoracic arteries
C. Inferior thyroid arteries
D. Subclavian arteries
A: bronchial arteries
which of the following statements about the carina is FALSE?
A) It is a cartilaginous ridge at the tracheal bifurcation
B) It is located at the level of the sternal angle (T4/T5)
C) It is more prominent in individuals with a narrow thoracic cavity
D) Its distortion may indicate metastasis to the inferior tracheobronchial lymph nodes
C) It is more prominent in individuals with a narrow thoracic cavity
the trachea begins at which vertebral level?
A) C3
B) C5
C) C6/C7
D) T1
C) C6/C7
the function of the alveolar ducts is to:
A) Humidify and warm the inhaled air
B) Serve as the final passage for air before reaching the alveoli
C) Secrete mucus to trap debris
D) Filter and condition the air
B) Serve as the final passage for air before reaching the alveoli (where gas exchange occurs)
why are foreign bodies more likely to enter the right bronchus in adults?
A) The right bronchus is narrower
B) The right bronchus is more horizontal
C) The right bronchus is wider and more vertical
D) The right lung has more alveoli
C) The right bronchus is wider and more vertical
which of the following structures is NOT located within the conducting portion of the airway?
A) Trachea
B) Primary bronchi
C) Respiratory bronchioles
D) Terminal bronchioles
C) Respiratory bronchioles
which of the following correctly describes the relationship between the trachea and the oesophagus?
A) The trachea is posterior to the oesophagus
B) The trachea is anterior to the oesophagus
C) The trachea and oesophagus are lateral to each other
D) The trachea passes through the oesophagus
B) The trachea is anterior to the oesophagus
what is the difference between the conducting and respiratory portions of the airway?
A) Conducting part is responsible for gas exchange, respiratory part only moves air
B) Conducting part moves air, respiratory part is where gas exchange occurs
C) Conducting part is in the lungs, respiratory part is in the trachea
D) There is no difference between them
B) Conducting part moves air, respiratory part is where gas exchange occurs
during bronchoscopy, which feature is used as a landmark for tracheal bifurcation?
A) Vocal cords
B) Carina
C) Inferior tracheobronchial lymph nodes
D) Cricothyroid ligament
B) Carina
what is the primary function of the trachealis muscle?
A) To keep the trachea rigid
B) To allow flexibility and diameter changes during breathing and coughing
C) To close the trachea when swallowing
D) To secrete mucus for trapping inhaled particles
B) To allow flexibility and diameter changes during breathing and coughing
during bronchoscopy, what finding would most likely indicate metastatic cancer in the inferior tracheobronchial lymph nodes?
A. A sharp, well-defined carina
B. A blunted, widened carina
C. A normal, thin carina
D. A carina with no visible ridges
B: a blunted, widened carina
which of the following is true about the venous drainage of the tracheobronchial tree?
A. The upper two-thirds of the trachea are drained by the bronchial veins.
B. The left bronchial veins drain directly into the superior vena cava.
C. The right bronchial veins drain into the azygos vein.
D. The inferior thyroid veins drain the lower one-third of the trachea.
C: the right bronchial veins drain into the azygos vein
(RIGHT bronchial veins > azygos vein > SVC)
what is the significance of the disappearance of hyaline cartilage in terminal bronchioles?
A. It increases resistance to airflow.
B. It makes the airways less susceptible to collapse.
C. It increases susceptibility to collapse.
D. It enhances gas exchange efficiency.
C: it increases susceptibility to collapse
which of the following nerves provides motor innervation to the trachealis muscle?
A. Vagus nerve
B. Recurrent laryngeal nerve
C. Sympathetic nerves
D. Phrenic nerve
C: sympathetic nerves (allows control over tracheal diameter)
which of the following is true about the lymphatic drainage of the tracheobronchial tree?
A. Lymph fluid drains directly into the thoracic duct.
B. The deep cervical lymph nodes are not involved in tracheobronchial drainage.
C. Pretracheal and paratracheal lymph nodes filter lymph from the tracheobronchial tree.
D. Lymphatic drainage is primarily through the bronchial lymphatic vessels.
C: pretracheal and paratracheal lymph nodes filter lymph from the tracheobronchial tree (and deep cervical LNs)
during a surgical procedure, a surgeon notices an abnormality in the venous drainage of the left bronchial tree. Which of the following pathways correctly describes the venous drainage of the left bronchial tree?
A. Bronchial veins → azygos vein → superior vena cava
B. Bronchial veins → accessory hemiazygos vein → hemiazygos vein → azygos vein → superior vena cava
C. Bronchial veins → inferior thyroid veins → brachiocephalic vein
D. Bronchial veins → internal thoracic vein → subclavian vein
B: bronchial veins → accessory hemiazygos vein → hemiazygos vein → azygos vein → superior vena cava
A patient undergoes surgery for a tracheal tumour located in the lower one-third of the trachea. Which artery is most likely responsible for supplying blood to this region, and what is its origin?
A. Inferior thyroid artery – branch of the subclavian artery
B. Superior thyroid artery – branch of the external carotid artery
C. Internal thoracic artery – branch of the subclavian artery
D. Bronchial artery – branch of the thoracic aorta
D: bronchial artery – branch of the thoracic aorta
