Anatomy of the Lower Respiratory Tract NOT FINISHED Flashcards
Why is the ‘thoracic cavity’ smaller than the thorax?
The boundaries of the thoracic cavity include the intercostal muscles laterally and the diaphragm inferiorly
What are the borders of the thoracic inlet?
What passes through it?
anteriorly - body of the manubrium
posteriorly - body of the first thoracic vertebra
laterally - the first ribs and their costal cartilages
- viscera: apex of lungs, thymus, trachea, oesophagus
- NAVL: common carotid artery, internal jugular vein, subclavian vein, phrenic nerves, vagus nerves, recurrent laryngeal nerves, thoracic duct
- muscles: SCM, anterior and middle scalenes, sternohyoid, sternothyroid
What are the main muscles of respiration? When are they used?
diaphragm - inspiration
external intercostals - inspiration
internal intercostals - expiration
innermost intercostals - expiration
What are the accessory muscles of forced expiration?
anterior abdominal wall
quadratus lumborum
latissimus dorsi
serratus posterior/inferior
What are the accessory muscles of forced inspiration?
pectoralis major and minor
serratus anterior
scalenes
sternocleidomastoid
What makes up the thoracic cage?
Sternum - manubrium, body, xiphoid process
12 thoracic vertebrae
ribs and costal cartilages
What are the borders of the thoracic inlet?
upper surfaces of first ribs and their costal cartilages
manubrium
body of T1
What are major organs in the media sternum?
trachea
oesophagus
heart + vessels
What are the 3 types of ribs?
Which ribs are in each category?
True ribs - attach the to sternum by their own cost. cart, 1st-7th
False ribs - 8th, 9th, 10th, cartilages attached to that of rib above, indirectly attached to sternum
Floating ribs - 11th, 12th, cartilages end in posterior abdominal wall musculature
What 5 muscles are innervated by the intercostal nerves
external intercostals internal intercostals innermost intercostals subcostals transversus thoracis
What are the other 3 muscles of thoracic?
serratus posterior anterior
serratus posteiror inferior
levator costarum
What are the attachments of diaphragm?
What are the hiatuses and their levels?
sternal costal lumbar T8 = vena cava T10 = oesophagus T12 = abdominal aorta
Describe the initial development of the lungs
Begins in 4th week of life as the median laryngotracheal tube in the floor of the primitive pharynx.
The trachea is separated from the oesophagus by the trachea-oesophageal septum.
Divides into 2 bronchial buds by the middle of the 5th week
What are the 4 stages of lung development?
What happens during each stage?
- pseudo glandular period (5-17weeks)
- major elements divides as far as terminal bronchioles
- has a distinct glandular appearance - Canalicular period (16-25weeks)
- lumina of bronchi and terminal bronchi enlarge
- respiratory bronchioles and alveolar duct develop
- lung tissue becomes highly vascularised - Terminal sac period (24-births)
- alveolar ducts develop terminal sacs (primitive alveoli)
- initially lined by simple cuboidal epithelium
- matures into squamous epithelium at 26 weeks
- capillaries come close to type 1 cells - Alveolar period (up to 8 years)
- 95% alveolar development
- initially terminal sacks separated by thin connective tissues
- become alveolar ducts in future
- terminal sac epithelium continue to thin
- adjacent capillaries infiltrate to form immature alveoli
Describe the gross anatomy of the lungs and trachea
Trachea extends from C6 to T4/T5 where it birfurcates into the right and left main branchus
Right bronchus is straighter, short and wider. It give rise to three lobar bronchi. Lobes are separated by oblique and horizontal fissure.
Left bronchus gives rise to 2 lobar bronchi. Lobes are separated by oblique fissure.
