Lea Lecture Lungs Flashcards
the lung is not in the pleural cavity it is….
surrounded by the pleural cavity
according to Dr. Lea
does anything penetrate the pleural cavity?
no it only contains a small amount of lubricating fluid
what is sibson’s fascia?
suprapleural membrane at the apex (thickened portion of the endothoracic fascia)
what is the upper respiratory tract
- Nose/nasal cavities/paranasal sinuses
- Pharynx
- Larynx
what is the lower respiratory tract
- Trachea
- Bronchi
- Lungs
what do the pulmonary cavities contain?
lungs
pleura
pleural cavity
what is the tracheobronchial tree
multiple levels of airway branching from trachea to alveoli (18-22 divisions)
where does the trachea start and where does it run in the superior mediastinum
starts at CV6 and runs through the midline of the superior mediastinum
when does the trachea bifurcate into right and left primary main bronchi
at the transverse thoracic plane (T4-T5)
what is the trachea composed of?
C-shaped hyaline cartilage bars
filled in posteriorly with longitudinal smooth muscle called trachealis (one of the only smooth muscle we name in the body)
what is the carina
last cartilage ring located at bifurcation of trachea; projects into lumen; identifiable on broncoscopy and on chest x-ray.
what is the vascular supply to the trachea
bronchial and inferior thyroid vessels
what is the lymphatic supply to the trachea
paratracheal lymph nodes
what is the innervation of the trachea
recurrent laryngeal branches of vagus nerves
what can cause the carina to become distorted?
Certain pathologies (bronchial carcinomas),due to spread of metastatic cancer cells into tracheobronchial (carinal) lymph nodes.
why do foreign objects typically lodge in the right bronchus
Right bronchus is wider, shorter, and more vertically oriented than the left bronchus
what do the primary bronchi give rise to and what is the difference in the right and left sides?
give rise to secondary (lobar) bronchi;
3 on the right (b/c there are 3 lobes on the right)
2 on the left (2 lobes on the left)
what do secondary bronchi give rise to?
further branch into tertiary (segmental) bronchi;
10 bronchopulmonary segments on the right
8 segments on the left
supply bronchopulmonary segments which are the smallest individually functional unit of the lung
what do tertiary branches give rise to?
branch 18 - 20 times;
bronchioles give rise to alveolar ducts;
alveolar ducts give rise to alveoli (thin-walled structures which compose the parenchyma of the lungs and are visualized using microscopy
what are the two pleural layers
what are they composed of?
what is their function?
what do they secrete?
parietal and visceral
- Composed of simple squamous epithelial cells + thin layer of loose connective tissue.
- Provide smooth surface for the lungs to move on during respiration.
- Secrete serosal fluid (a watery secretion derived from the blood supply) which fills the pleural cavity and provides lubrication.
what is the visceral pleura
- Intimately adherent to all external surfaces of the lungs (including fissures).
- Continuous with parietal pleura at the hilum of the lung.
what does the parietal pleura line
internal surface of thoracic wall
what are the surfaces of the parietal pleura
a. Costal
b. Diaphragmatic
c. Mediastinal – lines mediastinal surfaces; continuous with the visceral pleural at the root of the lung;
d. Cervical – extends superiorly into the root of the neck reaching its apex slightly superior to the neck of the first rib; reinforced by the suprapleural membrane (which is the thickened portion of the endothoracic fascia)
what forms the pulmonary ligament
what is the function of the pulmonary ligament
mediastinal surface of the parietal pleura and the visceral pleura
this inferior extension of pleura assists in maintaining position of lung in thoracic cavity
what is the vertebral line of reflection
costal pleura becomes continuous with mediastinal pleura posteriorly.
what is the costal line of reflection
costal pleura becomes continuous with diaphragmatic pleura inferiorly.
what is the sternal line of reflection
costal pleura becomes continuous with mediastinal pleura anteriorly
why is the extension of the cervical pleura (part of parietal pleura) into the root of the neck clinically important
may be punctured as a result of wounds in this region.
what happens if the pleura membranes become inflamed due to disease (pleuritis or pleurisy)?
they become rough and no longer slide easily over one another.
why is pleuritis painful?
because the parietal pleura receives extensive sensory innervation from intercostal and phrenic nerves. Thus, pain is referred to the area of the thoracic wall or to the point of the shoulder via the phrenic nerve(C3,4,5). The visceral pleura sensory nerves travel with autonomic fibers of the bronchial vessels.
what is the clinical significance of the left sternal reflection that passes inferiorly in medial plane to the level of the 4th costal cartilage and then turns laterally and inferiorly to the level of the 6th costal cartilage?
it creates a cardiac notch that allows a small part of the pericardium to be in direct contact with the anterior thoracic wall (bare area of the heart)
*** important for pericardiocentesis
what is the inferior level of the parietal pleura and the visceral pleura at the midclavicular line
visceral–> 6th rib
parietal–> 8th rib
what is the inferior level of the parietal pleura and the visceral pleura at the midaxillary line
visceral–> 8th rib
parietal –> 10th rib
what is the inferior level of the parietal pleura and the visceral pleura at the scapular line
visceral –> 10th rib
parietal –> 12th rib
what is a pleural recess?
Areas of pleural cavity which the lungs do not completely occupy during quiet respiration;
Two layers of parietal pleura come into contact with each other.
at 2 and 4 they are pretty much together