Lecture 1: The pleura and the lungs Flashcards
At what week does the embryo begin to develop a respiratory system?
4-6 Weeks
What layer do the lungs and pleura develop from?
Endoderm layer
What is formed following development of out pouches?
Lung buds
What are the two layers of pleura?
Visceral and parietal
What are the 4 parts of the parietal pleura?
Costal
Mediastinal
Diaphragmatic
Costal
What is between the two layers of of pleura?
Thin layer of serous fluid - allows them to slide against each other - also creates surface tension to keep the lungs held against the thoracic wall
What are the two pleural cavity recesses?
Costomediatinal and costodiaphragmatic
Visceral pleura doesn’t go all the way down to the diaphragmatic pleura – but it can do if it needs to – there is extra space to allow this
What is the innervation of the cervical, costal, mediastinal and diaphragmatic layers of the parietal pleura?
Cervical - 1st intercostal nerve
Costal - intercostal nerve
Mediastinal - phrenic nerve
Diaphragmatic - lower intercostals and phrenic nerves
What is the innervation of the visceral pleura?
Autonomic from the pulmonary plexuses
What fissures are present in the right lung?
Horizontal (divides superior lobe into superior and middle lobe)
Oblique – front to back (divides into superior and inferior lobe)
How does the size and shape of the right lung differ from that of the left lung?
Larger and heavier, shorter and wider
What are the key features of the left lung?
Oblique fissure
Cardiac notch
Lingula
What structures enter the lung at the hilum?
Main bronchus (posterior) Pulmonary artery (superior) Pulmonary veins (inferior) Bronchial arteries and veins Pulmonary plexus of nerves Lymph vessels and nodes
What is the purpose of bronchial arteries?
Supply oxygen and nutrients to the lung and visceral pleura
Where do bronchial veins terminate?
The azygos vein
Where do the left and right bronchial arteries branch from?
Left - from descending aorta
Right - from intercostals
What spinal segments does the trachea run from and to?
From C6to T4/5
What is the name of the muscle posterior to the trachea?
Trachealis muscle
At what level does the trachea bifurcate?
Sternal angle - T4/5
What is the name of the internal bifurcation point of the trachea?
Carina
How does the right main broncos compare to that of the left?
Wider, shorter and more vertical
How many secondary (lobar) bronchi are there in the right and left lungs?
Right - 3
Left - 2
What is supplied by a tertiary bronchus?
A bronchopulmonary segment
How many bronchopulmonary segments are there in the right and left lungs>
Right - 10
Left - 8-10
What is the name of the largest subdivision of a lung lobe?
Bronchopulmonary segment
What is special about the bronchopulmonary segments?
They are separated by connective tissue so are surgically resectable
How many generations of conducting bronchioles are there?
20-25
What makes respiratory bronchioles characteristic?
Out pockets of alveoli
What are alveoli ducts?
Elongated airways lined by alveoli which lead to common spaces called alveolar sacs
Which type of pneumocytes secrete pulmonary surfactant?
Type 2
What % of pneumocytes are type 1 and type 2?
Type 1 - 95%
Type 2 - 5%
What is the effect of sympathetic stimulation on bronchial musculature and pulmonary vasculature?
Bronchial musculature – dilates
Pulmonary vasculature – constricts
What is the effect of parasympathetic stimulation on bronchial musculature and pulmonary vasculature?
Bronchial musculature – constricts
Pulmonary vasculature - dilates
What are the main regions of lymph drainage from the hilum?
Brochopulmonary nodes
Tracheobronchal nodes
Paratracheal nodes
