Thorax 2 - Lungs & Pleura Flashcards
lungs; neurovasculature; lymphatics
what structure separates the thoracic cavity from the abdominal cavity and forms the inferior border of the lungs?
diaphragm
where are the lungs located in relation to the mediastinum?
the lungs are located on either side of the mediastinum, flanking the heart
what is the functional unit of respiration in the lungs?
alveoli - allows oxygen to diffuse into the blood & CO2 to diffuse out
how far do the lungs extend (from apex to inferior border)?
apex extends above the 1st rib into the root of the neck
inferior border of lungs reaches the costal margin
what are the two layers of the pleura? how do they differ?
visceral pleura - adheres close to the lung surface
parietal pleura - lines the ribcage & diaphragm (internal surface of the thoracic cavity)
what are the 4 divisions of the parietal pleura associated with the lungs?
cervical
diaphragmatic
costal
mediastinal
what are the 4 divisions of the parietal pleura? where are they located?
- diaphragmatic - covers the superior surface of the diaphragm
- cervical - extends above the 1st rib into the root of the neck
- costal - lines the inner surface of the ribs
- mediastinal - covers the lateral surface of the mediastinum (near the heart)
what is the thickened portion of the cervical parietal pleura called? what is its significance?
suprapleural membrane - provides structural support and protection to the cervical parietal pleura as it extends into the root of the neck
the suprapleural membrane is a thickening of WHAT pleura?
cervical parietal pleura - provides structural support & protection to the apex of the lung as it extends into the root of the neck
what is the pleural cavity?
pleural cavity is the small space between the visceral & parietal pleural layers
why is the pleural cavity important for lung function?
- negative pressure space; allows the lungs to expand and contract smoothly during breathing
- secretes lubricating pleural fluid & reduces friction between lungs and thoracic cavity
what would happen if the pleural cavity were compromised (e.g., due to a pneumothorax)?
the lungs may collapse due to the loss of negative pressure that allows them to inflate - impairs gas exchange
what is a haemothorax?
when blood enters the pleural cavity - causes loss of negative pressure & lungs may collapse
what are the two recesses of the pleural cavity?
costomediastinal recess
costodiaphragmatic recess
what are pleural recesses?
areas of the pleural cavity not completely filled with lung tissue
WHEN do pleural recesses become occupied by lung tissue?
occupied with lung tissue during INSPIRATION - remain empty during expiration
what happens to the costomediastinal recess during inspiration?
becomes occupied by lung tissue (especially the anterior border of the lungs)
where is the costodiaphragmatic recess located?
at the base of the pleural cavity - where the diaphragm meets the thoracic wall
what part of the lung occupies the costodiaphragmatic recess during inspiration - the base or apex of the lung?
base of the lung
primary function of pleural recesses?
provide additional space for lung expansion during deep inspiration
how are the pleural recesses affected during pleural effusion? which recess is more clinically significant in this case?
accumulate excess fluid - costodiaphragmatic recess is a common site for fluid accumulation & can be accessed for treatment
how many lobes & fissures does the right lung have?
3 lobes (superior, middle & inferior)
2 fissures (horizontal & oblique)
how many lobes & fissures does the left lung have?
2 lobes (superior & inferior)
1 fissure (oblique fissure)
what are the 3 surfaces of the lungs?
- costal surface - faces inner surface of ribcage
- diaphragmatic surface - contacts diaphragm
- mediastinal surfaces - faces mediastinum
which lung has the lingula - left or right?
left lung
what is the lingula?
a projection from the superior lobe of the left lung - normally lies on top of the heart
on what surface of the lung is the hilum found?
A: costal surface
B: diaphragmatic surface
C: mediastinal surface
D: cervical surface
C: mediastinal surface
how many pulmonary veins & arteries are present in each lung hilum?
2 pulmonary veins
1 pulmonary artery
at what vertebral level do the main bronchi divide from the trachea?
T4/5
what is the pulmonary ligament?
an extension of the pleura at the hilum - provides extra space/flexibility for the hilum to move slightly during breathing without constricting vessels
also allows the connection between the inferior lobe of the lung and the diaphragm
the pulmonary ligament allows the connection between WHAT two surfaces?
inferior lobe of the lung & diaphragm
which nerve passes anterior to the hilum of the lung on both sides?
phrenic nerve
which nerve passes posterior to the hilum of the lung on both sides?
vagus nerve
which structure is always superior to the pulmonary veins in the hilum?
pulmonary artery
what is the most posterior structure in the hilum of the lung?
bronchus
what three structures are present in the hilum of the lung?
pulmonary artery (1)
pulmonary veins (2)
main bronchus (1)
list 5 impressions on the mediastinal surface of the RIGHT lung
oesophagus
heart (right atrium)
inferior vena cava
superior vena cava
azygos vein
list 4 impressions on the mediastinal surface of the LEFT lung
oesophagus
heart (left ventricle)
thoracic aorta
arch of aorta
which of the following structures passes anterior to the hilum of the lung?
A) pulmonary artery
B) vagus nerve
C) phrenic nerve
D) thoracic aorta
C: phrenic nerve
the pulmonary ligament is formed by:
A) bronchus and pulmonary artery
B) visceral and parietal pleura
C) lymphatic and nervous plexus
D) vagus and phrenic nerves
B: visceral and parietal pleura (it’s an extension of the pleura at the hilum)
which of the following structures creates an impression on the mediastinal surface of the right lung?
A) azygos vein
B) left ventricle
C) thoracic aorta
D) arch of aorta
A: azygos vein
which of the following is the most posterior structure at the hilum of the lung?
A) pulmonary veins
B) pulmonary artery
C) bronchus
D) lymphatic vessels
C: bronchus
which of the following best describes the function of the pulmonary ligament?
A) prevents the lung from collapsing
B) provides flexibility for hilum movement during breathing
C) directs oxygenated blood from the lungs to the heart
D) anchors the heart to the diaphragm
B: provides flexibility for hilum movement during breathing
the vagus nerve contributes to which of the following in the lung?
A) diaphragmatic movement
B) pulmonary nerve plexus
C) venous return from the lung
D) pleural adhesion to the chest wall
B: pulmonary nerve plexus
in the hilum of the lung, the pulmonary artery is typically found:
A) inferior to the veins
B) posterior to the bronchus
C) anterior to the phrenic nerve
D) superior to the veins
D: superior to the veins
what is the order of structures in the lung hilum, from anterior to posterior?
pulmonary vein
pulmonary artery
bronchus
what do you call a ‘functionally independent unit of the lung’?
bronchopulmonary segment
what is a bronchopulmonary segment?
a functionally independent unit of the lung - each with its own bronchial, arterial, and venous supply, separated by connective tissue
why is bronchopulmonary segmentation clinically important?
allows for targeted surgical resection of a diseased segment (like cancer) without compromising the function of the rest of the lung
how many bronchopulmonary segments are in the right lung?
10
how many bronchopulmonary segments are in the left lung?
8-10 (anatomical variation)
which two arterial circuits are involved with the lungs?
- non-respiratory circuit (bronchial circulation) - supplies lung tissue itself
- respiratory circuit (pulmonary circulation) - for gas exchange
which arterial circuit of the lung supplies the lung tissue itself?
non-respiratory circuit (via bronchial arteries)
what artery supplies the non-respiratory structures of the lung? where do they arise from?
bronchial arteries (arise from the thoracic aorta)
from the root of the lung, where does lymphatic drainage go?
to tracheobronchial LNs near the carina - then to tracheal LNs up the trachea
describe sympathetic & parasympathetic innervation to the lungs
parasympathetic - from vagus nerve
sympathetic - originates from sympathetic fibres
what effect does activated parasympathetic innervation have on bronchioles of the lungs?
bronchoconstriction
what effect does activated sympathetic innervation have on bronchioles of the lungs?
dilates bronchioles
