The pleura and the lungs Flashcards
(23 cards)
Thoracic Cavity
Left pleural cavity – contains left lung
Right pleural cavity – contains right lung
Mediastinum – space between the 2 pleural cavities
Development of lungs and pleura
4-6 begins development from endoderm layer
Endodermal out pouches form lung buds
Rapid division of airways occurs
Lungs push into primitive thoracic cavity and take lining (V) with them
Visceral Pleura
Closely adheres to the lungs including the fissures
Creates a smooth and slippery surface
Connects to the parietal pleura and the hilum/root of the lung
Parietal Pleura
Lines the internal aspect of the thoracic wall
It is divided into 4 parts Costal (Internal rib cage) Mediastinal (Lateral wall of mediastinum) Diaphragmatic (Superior diaphragm) Cervical (Cervical region)
Pleural Cavity
Is the space between the 2 layers of pleura and contains a thin layer of serous fluid, which allows the pleurae to slide against it each.
The surface tension of the serous fluid provides cohesion to help the lungs be held against the thoracic wall. Hence the lungs expand as the thoracic cavity expand.
Pleurae outline
Space in between outlines the pleural cavity
Not symmetrical because of the heart
Recesses exist in the pleural cavity – excess space
Pleural innervation
Parietal Cervical – 1st intercostal nerve Costal – intercostal nerves Mediastinal – phrenic nerve Diaphragmatic – lower intercostals and phrenic nerves
Visceral
Autonomic from pulmonary plexuses
Lungs
Apex Base Lobes, created by fissures Surfaces (Costal, Mediastinal & Diaphragmatic) Borders (Anterior, Inferior & Posterior)
Right Lung
Larger and heavier, shorter and wider
Left Lung
Cardiac notch
Lingula
Hilum/Root of lungs
On medial aspect of lungs
Main bronchus (posterior) Pulmonary artery (superior) Pulmonary veins (inferior) Bronchial arteries and veins Pulmonary plexus of nerves Lymph vessels and nodes
Pulmonary Circulation
De-oxygenated blood from right ventricle enters lung via left or right pulmonary artery
Branches follow bronchopulmonary segments
Oxygenated blood returns to left atrium via left or right superior or inferior pulmonary veins
Bronchial circulation
Bronchial arteries supply oxygen/nutrients to lung and visceral pleura
Left arteries branch from descending aorta
Right arteries branch from intercostal arteries
Bronchial veins terminate in the Azygos veins
Trachea
Flexible tube – from larynx, runs from C6 to T4/5
Composed of c-shaped cartilage rings
Posteriorly - Trachealis muscle
Bifurcates at level of sternal angle
Lined by mucous membrane and cilia
Internal point of bifurcation
= CarinaPrimary Bronchi
One for each lung
Passing into lung at Hilum/Root
Right main bronchus is wider, shorter and runs more vertically
Contains cartilage
Secondary Bronchi
Secondary (Lobar) bronchi supply one lobe each hence:
3 in the right lung
2 in the left lung
Tertiary Bronchi
Each Tertiary bronchus supplies a bronchopulmonary segment.
Bronchopulmonary segments
The largest subdivision of a lobe
Supplied by a single tertiary bronchus
Receives a single branch of the pulmonary artery
Separated by connective tissue
Surgically resectable/ removable in isolation
Bronchioles
20-25 generations of conducting bronchioles
No cartilage in walls
Terminal bronchiole gives rise to several generations of respiratory bronchioles
Respiratory bronchioles characterized by out pockets of alveoli
Alveoli
Alveolar ducts are elongated airways lined by alveoli which lead to common spaces called Alveolar sacs
Each alveolus is surrounded by capillaries
Two cell types: Type 1 pneumocytes (95%) & Type 2 pneumocytes (5%)
Innervation of lung - Sympathetic
Sympathetic – from sympathetic trunk
Bronchial musculature – dilates
Pulmonary vasculature – constricts
Innervations of lung - parasympathetic
Parasympathetic – from vagus
Bronchial musculature – constricts
Pulmonary vasculature - dilates
Lymph drainage
Superior tracheobronchial node Bronchopulmonary (hilar) nodes Trachea (paratracheal) node Inferior tracheobronchial (carinal) node Bronchopulmonary (hilar) nodes
