Bronchi, Lungs, Pleura and Diaphragm Flashcards
What forms the bronchial tree?
Trachea, Primary bronchi, Lobar bronchi, Segmental bronchi
Where does the trachea extend from and to where?
From C6 to T4/5 and lowest ring of cartilage has a hook - CARINA
Where are the primary bronchi formed?
T4/5 with the RHS wider and more vertical than LHS
Where are the Lobar bronchi formed?
In the lungs and supply the lungs
Where do the Segmental bronchi supply?
The bronchopulmonary segments (self-contained independent units of lung tissue)
Where is the neck cut if immediate access to the trachea is needed?
Between the thyroid cartilage and cricoid cartilage
How many bronchopulmonary segments are there?
10 in each lung - smallest, functionally independent region: own neurovascular supply
Where are the lungs located?
In the thorax, separated by mediastinum
In what do the lungs lie?
Each free in its pleural cavity - apart from attachment to heart via pulmonary vessels and trachea at the hilum
What is the structure of the lungs?
Apex - rises 3/4cm above 1st costal cartilage
Base - concave, rests on convex diaphragm surface
What are the borders and surfaces of the lungs?
3 borders: Ant, post, inf.
3 surfaces: Costal, Mediastinal, Diaphragmatic
What does the diaphragm separates the lungs from?
RL from right lobe of liver
LL from left lobe of liver, stomach and spleen
What are the general features of the mediastinal surface of the lung?
Posterior in contact with thoracic vertebrae, anterior - concave to accommodate heart, with larger cardiac impression on LL than RL
Above and behind cardiac impression - hilum of lung
What is the structure of the left lung?
2 lobes - sup and inf - separated by oblique fissure
What vessel grooves can be seen on the apical surface of the left lung?
For aorta, left subclavian, braciocephalic vein
What are some important features on the left lung?
Oblique fissure, cardiac notch, pulmonary ligament
What is the structure of the right lung?
3 lobes: Sup, middle, inf
Sup separated by horizontal fissure, Inf by oblique fissure
Slightly larger than LL
What vessel grooves can be seen on the right lung?
Right subclavian artery, Sup vena cava, azygous vein, inf vena cava, oesophagus
What are some important structures on right lung?
Cardiac impression, Oblique fissure, Horizontal fissure, pulmonary ligament
What is the root/hilum of the lung?
The connective structures that join the mediastinal surfaces to the heart and trachea - all enveloped in pleura
What are the structures that form the hilum?
Primary bronchus, Pulmonary artery/ (2x)veins, Bronchial arteries/veins, pulmonary plexus of nerves (autonomic), lymph vessels and nodes
What is the pulmonary ligament used for?
Gives the lungs space to expand in the pleural cavity
What is the pleura?
Thin layer of flattened cells supported by connective tissue that lines each pleural cavity and covers exterior of lungs
How many layers for the pleura?
2: visceral (covers surface lungs and lines fissures between lobes) and parietal (lines inner surface of chest wall)
What happens to the pleura at the hilum?
Visceral and parietal are continuous with each other
How is the pleura in a healthy individual?
Pleural cavity is collapsed, but moist surfaces allow lungs to glide as the expand and collapse
How are both layers of the pleura stuck together?
By surface tension
What is the gestational origin of the pleura?
Buds from the laryngotracheal tube form and push into the coelomic cavities. Slowly the lungs grow into the cavity, with the cavity lining forming the parietal pleura and the lining which is pushed in by lungs, forms visceral , with pleural cavity in between
Where do the lungs end?
Around the 6th rib
Where does the pleural cavity end?
Around 8-10th ribs
Why is there so much space between lungs and pleural cavity?
Called costo-diaphragmatic recess - to allow for space in maximal inspiration
What is breathing controlled and produced by?
Controlled by NS and produced by skeletal muscle
How can the capacity of the thoracic cavity be increased?
Movements of the diaphragm and ribs
How does the mechanism of breathing work?
Pleural cavity is expanded by muscles in walls, then elastic lungs expand with it, sucking air down the trachea into the lungs
What does contraction of the diaphragm do?
Increases vertical dimension of the thoracic cavity, by pushing the abdominal viscera down to a point. Then the costal margin is raised
Where is the serratus anterior attached to?
Originates on the surface of upper 8/9 ribs and attaches to front border of scapula
What does the serratus anterior do?
Allows forward rotation of arm and upward rotation of the arm by moving the scapula
What happens when there’s increased thoracic capacity?
Intrapleural pressure decreases and entry of air through respiratory passages into lungs, causing them to expand
How is the diaphragm structured?
Ring of skeletal muscle from costal margin attached to tendinous sheet which stretches
How high does the diaphragm stretch?
It stretches so high that organs like the liver are covered by the diaphragm, pleura and lung
How do the ribs move in breathing?
When ribs elevate (ant ends thrust forward and upwards) ^ antero-posterior dimension of thoracic cavity AND at same time, ribs are everted ^ transverse diameter AND IIM and EIM stiffen rib cage for ^ efficiency of diaphragm
Why does the costal margin rising help breathing?
It widens the pleural cavities by raising drooping lateral parts of ribs (bucket handle motion)
What also occurs when costal margin raised?
Sternum is tilted upwards, ^ antero-posterior diameter of pleural cavities (Pump-handle motion)
What kind of activity is quiet expiration?
Passive as it doesn’t need muscle action
What does quiet expiration depend on?
Elastic recoil in elastic tissue throughout lungs and rib cage
How does deep/forced expiration occur?
Muscles in abdominal walls squeeze abdominal organs against diaphragm and pull lower ribs downwards
