Tracheobronchial tree and larynx Flashcards
Is there cartilage on posterior trachea
No - tracheal muscle instead
What is the trachea?
Fibrocartilagenous tube supported by c-shaped cartilage rings
Extends from larynx to C5/6
What is the hilum?
Root of the lung - blood vessels and bronchi enter
Layers of trachea
Mucosa: pseudostratified ciliated columnar epithelium
Submucosa: aerolar connective tissue with seromucosou glands and ducts
C-shaped ring of hyaline cartilage
Adventitia - aerolar connective tissue
Bronchial tree
- Trachea bifurcates at carina
- Main bronchi enters lungs at hilum
- Right: wider, shorter, more vertical
- Left: inferior to aortic arch, anterior to eosophagus and descending thoracic aorta
- Caught object is in in right main bronchus
- Left bronchi splits into 2 lobar bronchi and right splits into 3
- All separated by connective tissue
- Segmental bronchi are tertiary
Where does trachea bifurcate?
Carina
What do main bronchi form?
Lobar bronchi
How many lobes are on left?
2
How many lobes on right?
3
Bronchial tree
Main bronchi - lobar bronchi - segmental bronchi - bronchopulmonary segments
Segmental bronchi
- Divide into conducting bronchioles that end as terminal bronchioles
- Transport air, no alveoli
- Bronchioles lack cartilage
- Terminal bronchioles divide into respiratory bronchioles which divide into alveolar ducts
- These give rise to alveolar sacs
- Outpouchings (alveoli) structural units of gas exchange
- 300 million alveoli
- No surfactant means lungs collapse
Secondary bronchi
Hyaline cartilage
Tertiary bronchi
Pseudostratified ciliated columnar epithelium
Terminal bronchioles
Initially ciliated then simple columnar epithelium
No cartilage but smooth muscle
No goblet cells
Respiratory bronchioles
Simple squamous epithelium
Surfactant producing
Alveoli
Single cell layer of pneumocytes
Acute asthma
- Allergen causes sudden inflammation and contraction of bronchiole smooth muscle (bronchospasm), narrowing airways causing breathing difficulties and wheezing
- Salbutamol given to relax airways, steroids
Cystic fibrosis
- Autosomal recessive
- Deranged atransport of chloride and other ions alters viscocity of mucous, making patient more prone to infections, damaging bronchi amnd resulting in bronchiectasis
- Bronchiectasis: permanent dilation of central and medium sized airways - can’t clear secretions
COPD
- Long term exposure to particles damages lung lining
- Chronic bronchitis
- Emphysema (tissue destruction)
- Bronchiolitis (small airway inflammation and fibrosis)
- Resistance to airflow in small airways increased compliance of lungs, air trapping
Blood supply
Bronchial arteries supply blood to nutrition to lungs, structures of root of lungs and visceral pleura
Two left bronchial arteries (thoracic aorta)
Single right bronchial artery
Larynx
- Anterior neck
- Functions: phonation, cough reflex, protection of lower respiratory tract
- Structure: primarily cartilaginous skeleton
- Ligaments and membranes
- Laryngeal muscles move larynx for phonation and breathing
- Suspended from hyoid
- C3-6
- Superiorly is pharynx
- Inferiorly is trachea
- Anteriorly is infra-hyoid muscles
- Laterally is thyroid gland
- Posteriorly is oesophagus
- Supra-glottis: inferior surface of epiglottis to vestibular folds
- Glottis: vocal apparatus, contains vocal cords
- Subglottis/infra-glottis: vocal folds to trachea
Laryngeal cartilage unpaired
Epiglottis, thyroid and cricoid
How to artificially close oesophagus
Put pressure on cricoid cartilage
Paired laryngeal cartilage
Arytenoid cartilage (attaches to vocal ligament)
Corniculate
Cuneiform
Arytenoid cartilage
Anterior vocal process - attaches to vocal ligament
Apex attaches to aryepiglottic folds
Crico-arytenoid joints - approximate, tense and relax vocal folds
True vocal cords
Non-keratonised stratified squamous epithelium
Contains Reinke’s space to allow vibration of epithelium
Rima glottidis = space between vocal folds
False vocal cords
Vestibular ligament covered by mucous membrane
Provide protection to larynx
Superior laryngeal nerve
Internal branch provides sensory innervation to supra glottis
External branch provides motor innervation to cricothyroid muscle
Inferior laryngeal nerve
Continuation of recurrent laryngeal nerve
Sensory innervation to infraglottis
Motor innervation to internal muscles of larynx except cricothyroid
Damage to nerve can be caused by
Apical lung tumour Thyroid cancer Aortic aneurysm Cervical lymphadenopathy Iatrogenic causes
Unilateral RLN palsy
Hoarseness
Increased risk of aspiration
Bovine cough
Bilateral RLN palsy
Cords adducted
Breathing impaired (stridor, snoring)
Phonation can’t occur
extrinsic muscles
Move larynx superiorly and inferiorly - supra hyoid and infra hyoid and stylopharyngess
Supra- and infra hyoid muscle groups attach to hyoid - bound to larynx by strong ligaments
Suprahyoid muscles and stylopharyngeus elevate larynx , infra hyoid muscles depress larynx
Extrinsic laryngeal ligaments
Thyrohyoid membrane hyo-epiglottoic ligaments - connects hyoid bone to anterior aspect of epiglottis
Cricotracheal ligament
Median cricothyroid ligament
Intrinsic laryngeal ligaments
Cricothyroid ligament
Quadrangular ligament
Cricothyroidotomy
Temporary airway in situations where larynx is obstructed
Superior laryngeal artery
Branch of superior thyroid artery - supplies internal surface larynx
Inferior laryngeal artery
Branch of inferior thyroid artery - supplies mucous membrane and muscles of inferior larynx
venous drainage
Superior and inferior laryngeal veins
Superior laryngeal veins drain to internal jugular vein via superior thyroid
Inferior laryngeal vein drains to left brachiocephalic vein via inferior thyroid vein
