Pleural Cavities Flashcards
Describe the Trachea
- C-shaped hyaline cartilaginous rings
- Bifurcates into right & left main bronchus at TIV/TV
- Carina – hook-shaped tracheal ring
- Trachealis muscle
What are the differences between the right and left main bronchi of the bronchial tree?
R: =Wider =Vertical =Shorter =Divides into 3 L: =Long =More horizontal =Thin =Divides into 2
What is the order of the bronchial tree?
- Trachea
- Main bronchus (primary)
- Lobar bronchi (3R, 2L) (secondary)
- Segmental bronchi (tertiary)
- Conducting bronchioles
- Respiratory bronchioles
- Alveoli
- Alveolar ducts
- Alveolar sacs
Describe alveoli
-Microscopic air cells
-Gas exchange
-150-300 million in adult lungs
-Single layer of epithelial cells & elastic fibres line the walls of each alveolus
=Allow them to stretch/ contract during breathing
-Surrounded by a network of capillaries for gas exchange
-Coated in a thin film of pulmonary surfactant
=Prevents alveoli from collapsing
Describe the lungs
- Organs of gaseous exchange
- Elastic connective tissue
- Small airways, blood vessels, nerves & lymphatic tissue
What are the external features of the lungs?
Right: -Superior, Middle and Inferior lobes -Oblique fissure -Horizontal fissure Left: -Superior and Inferior lobes -Oblique fissure -lingula
What are the external borders of the lung?
Right: -Anterior border -Costal surface -Inferior border -Mediastinal surface -Apex Left: -Apex -Mediastinal surface -Posterior border -Base (diaphragmatic surface)
Describe the right medial surface if the lungs
-Hilum =Where important structures enter/ exit each lung -Root structures =Pulmonary arteries =Pulmonary veins =Bronchus -Impressions =Superior vena cava =Inferior vena cava =Oesophagus =Azygos vein
Describe the left medial surface of the lungs
-Smaller than right lung-
-Hilum
=Where important structures enter/ exit each lung
-Root structures
=Pulmonary arteries
=Pulmonary veins
=Bronchus
-Impressions
=Heart
=Aortic arch
=Thoracic aorta
=Oesophagus
=Left subclavian artery
Describe the hilum
=Root =Hilum =Pulmonary ligament -Main structures entering the hilum =Primary bronchi =Pulmonary arteries (deoxygenated blood) -Main structures exiting the hilum =Pulmonary veins (oxygenated blood) -Other structures: =Bronchial arteries & veins =Lymph vessels =Efferent & afferent autonomic nerves
Describe the blood supply to the lungs
- Left and Right pulmonary artery
- Lobar and segmental arteries and veins
- Left pulmonary veins
What is the pleura of the lungs?
=Two pleural cavities (R & L)
=Lining membrane
=Pleural sac
-Parietal pleura =Costal =Mediastinal =Diaphragmatic =Cervical
-Visceral pleura
=Adheres to walls of lung
=Covering surface of each lobe
During development the lung is pushed into the sac to form the two layers
What is the role of the pleura in collapse of lungs?
- Separated by mediastinum
- Rupture of a lung allows entry of air into pleural cavity
- Surface tension adhering visceral to parietal pleura breaks = lung collapses
- Wont affect other lung
Describe the surface anatomy of the lungs
- Lungs don’t completely fill the pleural cavity
- Potential spaces
- Expansion of lungs into these spaces occurs during forced inspiration
- Midclavicular and midaxillary lines
- Turns laterally at 6th costal cartilage
- Crosses midaxillary line at Rib X
- Crosses midclavicular line at Rib V111
What is the Costo- diaphragmatic recess?
- Between costal pleura and diaphragmatic pleura
- Clinically important
What is the surface anatomy of the rib cage?
- Apex of right lung (above clavicle)
- Superior lobe of R lung (Rib 2 and 3)
- Middle lobe of R lung (Rib 4 and 5)
- Inferior lobe of R lung (Rib 6)
- Apex of L lung (Rib 1/2)
- Superior lobe of L lung (Rib 3 and 4)
- Inferior lobe of L lung (Rib 7 and 8)
What are the contents of the mediastinum?
- Aorta
- Heart
- Azygous vein
- Trachea
- Main bronchi
- Oesophagus
- Vagus nerves
- Phrenic nerves
- Posterior intercostal a and v
Describe the innervation to the pleura
-Parietal pleura – somatic innervation
-Costal pleura – intercostal nerves
-Mediastinal pleura – phrenic nerves
-Diaphragmatic pleura
=phrenic nerves to domes
=Lower 5 intercostal nerves to periphery
-Visceral pleura – autonomic innervation
Describe the innervation to the mediastinum
-Vagus nerve
=Parasympathetic supply to all organs of thorax
-Phrenic nerve
=Motor & sensory to diaphragm
What are the landmarks of the anterior surface of the thoracic walls?
- Suprasternal notch
- Sternal angle
- Xiphosternal joint
- Costal margin
- Clavicle
- Ribs
What are the landmarks of the posterior surface of the thoracic walls?
- Spinous process (thoracic vertebrae)
- Superior angle of scapula
- Spine of scapula
- Inferior angle of scapula
Where is the parietal pleura?
- Lines the thoracic walls and extends above the medial third of the clavicle by approximately 2.5cm
- From this point, the parietal pleura of each side descend down to pass behind each sternoclavicular joint and continue until they meet just lateral to the midline at the level of the sternal angle
Where is the inferior edge of the lungs?
Lungs sit approximately 2 ribs above the pleura, leaving a space inferiorly
What is the space inferior to the lungs?
Costodiaphragmatic recess
