TBL 9: Pleurae/Lungs Flashcards
What separates the right and left pleural cavities?
The continuity of the visceral/parietal pleurae at the roots of the lungs completely separate the right and left pleural cavities.
Identify the parts of the parietal pleural, A through C in the image below.
What makes up the costodiaphragmatic recesses and why are these recesses possible?
The lowest part of the costal pleura can come in contact with the peripheral part of the diaphragmatic pleura, creating costodiaphragmatic recesses.
The reason this is possible is because the lungs do not fully occupy the pleural cavities during normal respiration.
How does the thin fluid layer in the pleural cavity normally sustain inflation of the lungs during inspiration?
The thin pleural fluid layer in the pleural cavity provides surface tension that allows the outer surfaces of the lungs to adhere to the inner surface of the thoracic walls.
How is fluid sampled in the costodiaphragmatic recess without damaging the inferior border of the lungs? How do contents of the ribs’ costal grooves determine proper execution of the procedure?
The patient must first exhale while in the upright position to decrease the size of the lungs (this also allows the intrapleura fluid to accumulate in the costodiaphragmatic recess). A hypodermic needle is then inserted superior to the rib at an upright angle (to avoid damage to the intercostal nerve/vessels and deep side of the costodiaphragmatic recess) through an intercostal space (usually the 9th to avoid the inferior border of the lung) past the intercostal muscles and costal parietal pleura into the pleural cavity.
How is fluid sampled in the costodiaphragmatic recess without damaging the inferior border of the lungs? How do contents of the ribs’ costal grooves determine proper execution of the procedure?
Fluid is sample in the costodiaphragmatic recess by inserting a hypodermic needle at an upright angle into the 9th intercostal in the mid axillary line during expiration to avoid the inferior border of the lung and to avoid penetrating the deep side of the recess.
The location of the intercostal nerve and vessels on the inferior border of the ribs, means that the best place to insert the needle is on the superior border of a rib.
Why can irritation of the parietal pleural produce either local or referred pain?
The parietal pleural is richly supplied by branches of the intercostal and phrenic nerves, as opposed to the visceral pleura which is insensitive pain since it receives no nerves of general sensation.
What structure covers the apex of the lungs?
The cervical pleura and extends into the root of the neck.
Describe the symptoms and cause/associations of Pancoast’s syndrome.
Pancoast’s syndrome is caused by an apical lung tumor compressing the trunks of the brachial plexus, resulting in pain extending down the ipsilateral arm into the hand.
It is usually associated with a history of smoking.
What could happen if an apical tumor compresses the sympathetic trunk?
If an apical lung tumor compresses the sympathetic trunk, the ipsilateral eye could be affected (Horner’s Syndrome).
What would happen to the pleural cavity after a gunshot through one side of the thoracic wall?
A penetrating wound through one side of the thoracic wall would rupture the parietal pleural and allow air to enter the pleural cavity, creating a pneumothorax. Atmospheric pressure would subsequently force air into the thoracic cavity on this side, collapsing the ipsilateral lung.
What would occur if there was a penetrating wound to one side of the thoracic cavity, with the presence of a tissue flap that allowed air to enter but not leave the pleural cavity?
In a penetrating wound to the thoracic cavity with a tissue flap, air would continually seep into the thoracic cavity but would not be allowed to escape so the increasing pressure on this side of the thoracic cavity would eventually permanently push the heart to the contralateral side, creating a tension pneumothorax which can be fatal.
Why is the cervical pleura vulnerable during infancy and early childhood?
The cervical pleura is especially at risk during infancy and early childhood because this is when the apex of the lung and cervical pleura project the highest through the opening in the neck made by the inferior slope of the 1st pair of ribs and the superior thoracic aperture they form due to the relative shortness of their necks.
What are common causes of:
a) pneumothorax?
b) hydrothorax?
c) hemothorax?
Common causes of:
- a) pneumothorax* - entry of air in the pleural cavity resulting from a penetrating wound or rupture of a pulmonary lesion
- b) hydrothorax* - accumulation of a significant amount of fluid in the pleural cavity possibly resulting from a pleural effusion (escape of fluid into the pleural cavity)
- c) hemothorax* - entry of blood into the pleural cavity most commonly a result of injury to a major intercostal or internal thoracic vessel.
With a pneumothorax, why is the mediastinum only shifted toward the affected side during expiration?
When there is a puncture wound in one side of the thoracic cavity (pneumothorax), atmospheric air is going to rush into this area of negative pressure (pleural cavity). So now instead of a cavity full of negative pressure, this cavity equilibriates with the atmospheric pressure and becomes a normal empty space full of air. This atmospheric air breaks the surface tension between the lung and the surrounding pleural wall, collapsing the lung and usually decreasing the overall size of that thoracic cavity.
During normal expiration, the diaphragm and external intercostal muscles relax, allowing the thoracic cavity to decrease in size and essentially squeeze air from the lungs into the atmosphere. In the case of the situation described above, only the unaffected side of the thoracic cavity has an inflated lung that can expire air so when expiratory relaxation of the thoracic cavity occurs, the unaffected side is the only side to have the normal increased pressure, thus pushing the mediastinum toward the affected side.
Identify structures A through M in the image below.
Identify structures A through K in the image below, bitch.
Identify structures A through K in the image below, you wont..
At what landmark does the trachea and pulmonary trunk bifurcate into the left and right main bronchi and pulmonary arteries?
What do the main arteries and bronchi subsequently divide into?
At the level of the sternal angle, the trachea and pulmonary trunk bifurcate into the left and right main bronchi and pulmonary arteries.
The main arteries subsequently divide into lobar arteries and bronchi subsequently divide into bronchi that supply the lobes of the lungs.
Which main bronchus is more likely to lodge an aspirated foreign body?
The right man bronchus is more likely to lodge an aspirated foreign body due to the fact that it is wider, shorter, and runs more vertically than the left main bronchus.
What is the primary cause of bronchogenic carcinomas and where do primary tumors most commonly arise? Why is the brain a common site of hematogenous metastasis?
The primary cause of bronchogenic carcinoma (lung cancer) is mainly cigarette smoking.
Primary tumors usually arise in the mucosa of the large bronchi and produce a persistent, productive cough or hemoptysis (spitting of blood). Malignant cells can be detected in the sputum.
The brain is a common site of hematogenous metastasis (spreading through the blood) of cancer cells because the cells most likely enter the systemic circulation by invading the wall of a sinusoid or venule in a lung.
Identify structures A through I in the image below.
Identify all of these structures ;)
Identify structures A through I in the image below.
Where does lymph from the lungs drain into first, then second, then last?
Lymph from the lungs first drains into the hilar lymph nodes, then secondly drain into the tracheobronchial lymph nodes at the tracheal bifurcation, then ultimately drain at te right and left bronchomediastinal trunks.
What doe the cardiopulmonary splachnic nerves consist of?
The cardiopulmonary splachnic nerves consist of post-synaptic sympathetic fibers from the paravertebral ganglea at T1-T5, which instead of returning to the spinal nerves via the gray communicating rami, directly enter the hilum of the lungs.
Where do presynaptic parasympathetic fibers of the vagus nerve travel?
pre-synaptic parasympathetic fibers of the vagus nerve (10th cranial nerve) enter the hilum and synapse with postsynaptic neurons of parasympathetic ganglia within the walls of the bronchi and bronchioles.
What nerve vessels accompany all branches of the bronchi and bronchioles?
parasympathetic and sympathetic fibers form the right and left pulmonary plexuses that accompany all branches of the bronchi and bronchioles.
