Pleural cavities and lungs Flashcards
Pleura
thin, serous membrane that covers the lungs and lines the inside of the chest wall
What are the layers of the pleura?
2 layers
- Visceral pleura
- Parietal pleura
Visceral pleura
Innermost layer and covers the surface of the lungs
Parietal pleura
outermost layer and lines the inside of the chest wall
What separates the two layers of pleura?
Small amount of pleural fluid / pleural cavity
Which pleural layer adheres more closely to the surface of the lungs?
Visceral pleura
What does the pleural fluid do?
Separates the two layers
Reduces friction which allows the layers of pleura to slide easily over each other during breathing
When you inhale what does the diaphragm do?
Diaphragm contracts to let more air in
When you exhale what does the diaphragm do?
Diaphragm relaxes / expands
pleurisy
a condition in which the pleura become inflamed, causing chest pain and difficulty breathing
pneumothorax
a condition in which air enters the pleural cavity, causing the lung to collapse
pleural effusion
excess fluid accumulates in the pleural cavity
puts pressure on lungs and makes it difficult to breathe
How do you normally treat pneumothorax?
insert a chest tube to remove excess air
How can you treat a pleural effusion?
with thoracentesis to drain the excess fluid
What is the opening at the top of the thorax called?
the superior thoracic aperture OR thoracic outlet
What traverses the thoracic outlet?
the suprapleural membrane
What does the suprapleural membrane do?
prevents the lungs from expanding up into the neck
What makes the floor of the “thoracic” cone / bottom cone extending along costal cartilage?
diaphragm muscle
What separates the thoracic cavity from the abdominal cavity?
diaphragm
What is a serous membrane?
double layered membrane
parietal and visceral layers
the two layers are continuous
How can you remember visceral / parietal layers?
imagine pushing a balloon in
the layer closest to fist is visceral layer
the outer layer of the balloon is the parietal layer
notice that they connect
in between the layers is a cavity
What is another example of a serous membrane in the body?
the pericardium
How does the parietal pleura change its name?
Becomes costal by ribs, cervical by clavicle, diaphragmatic by diaphragm, mediastinal pleura
mediastinum
space in your chest that holds your heart and other important structures, like esophageous and trachea
What are the two recesses? What are they?
Space formed by the parietal pleura
Never filled
costophrenic recess (where costal becomes diaphragmatic pleura)
costophrenic recesses hang below the end of the lung
costomediastinal recesses too (where costol becomes medistinal pleural)
Are the pleural symmetric? Why or why not?
No
Due to the position of the apex of the heart
Apex points towards the left
Where does the pericardium align with the pleura directly? Why is this important?
On the left side
Important to do pericardiocentesis (remove fluid from heart)
thoracic skeleton
rib cage and thoracic vertebral column
irregularly shaped cone
What passes through the superior thoracic aperture?
trachea, esophagus, many vessels / nerves
What are the boundaries of the superior thoracic aperture?
T1
rib 1 and costal cartilage
jugular notch of the manubrium
boundaries of the inferior thoracic aperture
T12
costal margin
xiphosternal joint
What bounds the thoracic cavity?
thoracic wall, diaphragm, suprapleural membrane
suprapleural membrane
thickening of fascia above the superior thoracic aperture which limits bulging of the lungs into the neck
where are the parietal and visceral pleural continous with each other?
around the root of the lung
draw this out!
costal pleura
lines the thoracic wall
cervical pleura (cupola)
extends through the thoracic inlet into the neck
Diaphragmatic pleura
covers the diaphragm
Mediastinal pleura
covers the mediastinal surface of each pleural sac
do the lungs ever fill the entire pleural space?
No!
What do recesses allow for?
space for fluid to accumulate
Costodiaphragmatic recesses
at the sharp reflection of the costal pleura
onto the diaphragmatic pleura
at the bottom of lungs
costomediastinal recesses
at the sharp anterior reflections of the costal
pleura onto the mediastinal pleura
pulmonary ligament
double layer of mediastinal pleura
surrounds lung hilum
extends downwards at the lung base
what does right pleura look like overall?
continues straight downward close to the midline
swings outward and downward at the xiphosternal joint
what does the left pleura look like?
anteriorly deviates laterally at the 4th costal cartilage
lateral to the sternum at 5th and 6th intercostal spaces
creates a shallow notch around direct area of contact between pericardial sac and anterior thoracic wall
swings outward and downward at the xiphosternal joint
Which pleura is larger?
the left due to the notch created by the apex of the heart
How is the mediastinum divided?
superior and inferiorly
at the sternal angle and lower border of T4
what limits the mediastinum superiorly?
superior thoracic aperture
what limits the mediastinum inferiorly?
diaphragm
How is the inferior mediastinum further divided?
anterior mediastinum, middle mediastinum, posterior mediastinum
middle mediastinum
contains the pericardial sac and its contents
what limits the superior mediastinum?
located behind the manubrium
limited posteriorly by T4
where is the posterior mediastinum?
situated behind the pericardial sac extending from T5 to T12
anastomose definition
to be linked at
what is a line of pleural reflection?
where costal pleural changes direction to become mediastinal or diagphragmatic pleura
creates recesses
where is the mediastinum split at?
T4
is the mediastinum itself a pleural cavity?
No! It is a space that lies between the L and R pleural cavities
