Tracheobronchial tree and larynx

Question 1

Is there cartilage on posterior trachea

Answer 1

No - tracheal muscle instead

Question 2

What is the trachea?

Answer 2

Fibrocartilagenous tube supported by c-shaped cartilage rings
Extends from larynx to C5/6

Question 3

What is the hilum?

Answer 3

Root of the lung - blood vessels and bronchi enter

Question 4

Layers of trachea

Answer 4

Mucosa: pseudostratified ciliated columnar epithelium

Submucosa: aerolar connective tissue with seromucosou glands and ducts

C-shaped ring of hyaline cartilage

Adventitia - aerolar connective tissue

Question 5

Bronchial tree

Answer 5

• 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

Question 6

Where does trachea bifurcate?

Answer 6

Carina

Question 7

What do main bronchi form?

Answer 7

Lobar bronchi

Question 8

How many lobes are on left?

Answer 8

2

Question 9

How many lobes on right?

Answer 9

3

Question 10

Bronchial tree

Answer 10

Main bronchi - lobar bronchi - segmental bronchi - bronchopulmonary segments

Question 11

Segmental bronchi

Answer 11

• 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

Question 12

Secondary bronchi

Answer 12

Hyaline cartilage

Question 13

Tertiary bronchi

Answer 13

Pseudostratified ciliated columnar epithelium

Question 14

Terminal bronchioles

Answer 14

Initially ciliated then simple columnar epithelium
No cartilage but smooth muscle
No goblet cells

Question 15

Respiratory bronchioles

Answer 15

Simple squamous epithelium

Surfactant producing

Question 16

Alveoli

Answer 16

Single cell layer of pneumocytes

Question 17

Acute asthma

Answer 17

• Allergen causes sudden inflammation and contraction of bronchiole smooth muscle (bronchospasm), narrowing airways causing breathing difficulties and wheezing
• Salbutamol given to relax airways, steroids

Question 18

Cystic fibrosis

Answer 18

• 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

Question 19

COPD

Answer 19

• 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

Question 20

Blood supply

Answer 20

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

Question 21

Larynx

Answer 21

• 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

Question 22

Laryngeal cartilage unpaired

Answer 22

Epiglottis, thyroid and cricoid

Question 23

How to artificially close oesophagus

Answer 23

Put pressure on cricoid cartilage

Question 24

Paired laryngeal cartilage

Answer 24

Arytenoid cartilage (attaches to vocal ligament)
Corniculate
Cuneiform

Question 25

Arytenoid cartilage

Answer 25

Anterior vocal process - attaches to vocal ligament Apex attaches to aryepiglottic folds Crico-arytenoid joints - approximate, tense and relax vocal folds

Question 26

True vocal cords

Answer 26

Non-keratonised stratified squamous epithelium Contains Reinke's space to allow vibration of epithelium Rima glottidis = space between vocal folds

Question 27

False vocal cords

Answer 27

Vestibular ligament covered by mucous membrane | Provide protection to larynx

Question 28

Superior laryngeal nerve

Answer 28

Internal branch provides sensory innervation to supra glottis External branch provides motor innervation to cricothyroid muscle

Question 29

Inferior laryngeal nerve

Answer 29

Continuation of recurrent laryngeal nerve Sensory innervation to infraglottis Motor innervation to internal muscles of larynx except cricothyroid

Question 30

Damage to nerve can be caused by

Answer 30

``` Apical lung tumour Thyroid cancer Aortic aneurysm Cervical lymphadenopathy Iatrogenic causes ```

Question 31

Unilateral RLN palsy

Answer 31

Hoarseness Increased risk of aspiration Bovine cough

Question 32

Bilateral RLN palsy

Answer 32

Cords adducted Breathing impaired (stridor, snoring) Phonation can't occur

Question 33

extrinsic muscles

Answer 33

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

Question 34

Extrinsic laryngeal ligaments

Answer 34

Thyrohyoid membrane hyo-epiglottoic ligaments - connects hyoid bone to anterior aspect of epiglottis Cricotracheal ligament Median cricothyroid ligament

Question 35

Intrinsic laryngeal ligaments

Answer 35

Cricothyroid ligament | Quadrangular ligament

Question 36

Cricothyroidotomy

Answer 36

Temporary airway in situations where larynx is obstructed

Question 37

Superior laryngeal artery

Answer 37

Branch of superior thyroid artery - supplies internal surface larynx

Question 38

Inferior laryngeal artery

Answer 38

Branch of inferior thyroid artery - supplies mucous membrane and muscles of inferior larynx

Question 39

venous drainage

Answer 39

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