Week 11 finished Flashcards
What is the extent of the pleural cavity?
- Superior: The pleural cavities extend above rib 1 into the root of the neck superiorly. Here the pleura is reinforced by Sibson’s Fascia.
- Inferior: The pleural cavities end at a level just above the costal margin. *At these locations it is susceptible to injury during abdominal surgery.
- Medial: The are bordered medially by the mediastinum.
How is the thoracic cavity divided?
-Divided into 3 cavities: right and left pleural (or pulmonary) and mediastinum.
What is the lung pleura?
Each lung is invested by and enclosed in a serous pleural sac that consists of two continuous membranes: the visceral pleura, (which invests all the surfaces of the lungs forming a shiny outer surface) and the parietal pleura (which lines the pulmonary cavities).
-The pleural cavity (potential space between these two layers) contains a capillary layer of serous pleural fluid, allows the two layers to slide smoothly over each other. during respiration.
Anatomy of the pleura layers?
The visceral pleura (pulmonary pleura)- is adherent to the lung including in the horizontal and oblique fissures. It is shiny and slippery for movement against the parietal pleura.
The parietal pleura: covers the ribs, mediastinum and diaphragm; Thicker of the two pleura.
The parietal pleura is further named for the adjacent structures: mediastinal, costal, diaphragmatic, cervical pleura.
Nerve supply to the lung pleura layers?
Lungs and Visceral Pleura
o Parasympathetic – Vagus
o Sympathetic – Pulmonary Plexus – T1-6 via cardiopulmonary splanchnic
o Visceral pleura insensitive to pain
Parietal Pleura
o Costal aspect - Intercostal Nerves
o Mediastinum and Diaphragm – Phrenic Nerve
o Extremely Pain Sensitive
o Refers: thoracic or abdo wall or neck and shoulder, cervical spine (phrenic), diaphragm
What is pneumothorax and how does it occur?
The pressure in the pleural cavities (between visceral and parietal pleural layers) is subatmospheric. This helps to keep the lung distended during expiration.
- If a hole opens up through the thorax (wound) or the lung (rupture of pulmonary lesion, rib fracture), air is sucked into the pleural cavity because of the negative pressure.
- The surface tension adhering the pleural layers is broken and the lung will collapse (pneumothorax).
List the structures forming the root of the lung? and the role of each?
The root of the lung is a tubular collection of structures attaching the lung to the mediastinum. The hilum is the name given to the lung surface where the root is attached.
Each root contains:
• a pulmonary arteries (which carries deoxygenated blood from the right ventricle)
•two pulmonary veins (which deliver oxygenated blood to the left atrium)
•main bronchus (airway)
•bronchial vessels (arteries and veins provide nutrition to the root of the lung, support tissues and visceral pleura),
•nerves (innervate the lungs)
•lymphatics (drain lungs)
How many lobes does the Right and Left lung have? Name the fissures of the Right and Left Lungs.
The Right lung has three lobes: It has a horizontal fissure and a right oblique fissure. 3 lobes are: 1. Superior, middle and inferior lobes
The Left lung has two lobes: It has a left oblique fissure separating the 1. Superior 2. Inferior lobes.
Right lung shorter and wider due to the right dome diaphragm and the liver. However right lung overall is bigger due to the cardiac notch in the left and mediastinum is more left.
How can restriction at the thoracic inlet influence
lymphatic drainage from the lung?
The lymphatics from the lungs join the thoracic duct and the right thoracic duct meaning that all lymphatic fluid from the lungs must pass through the thoracic inlet before joining the venous system for return to the heart.
-Fascial restrictions of the thoracic inlet and pectoral fascia can cause lymphatic stasis of the upper limb.
What nerves supply the lungs? From what levels is the sympathetic innervation derived?
Posterior & Anterior Pulmonary plexus:
- Vagus nerve (parasympathetic; Parasympathetic stimulation bronchoconstricts, vasodilates and is secretomotor)
- T1-6 sympathetic via cardiopulmonary splanchnic nerves
What surface anatomy is used to identify the
extent of the normal lung fields?
Superior margin = Lung apices, cervical pleurae pass through the superior thoracic aperture deep to the supraclavicular fossa, and lateral to the tendons of SCM.
Anterior border= lie between 2nd and 4th costal cartilage. The anterior border than moves laterally and inferior to 6th costal cartilage.
Inferior border = midclavicular line of the 8th rib and the scapular line at the 10th rib, proceeding toward the 10th vertebra SP.
Oblique fissures= SP T2 to 6th costal cartilage anteriorly.
Horizontal fissure on right = from oblique fissure to the 4th rib and costal cartilage anteriorly.
Where would you place the stethoscope to
examine the lower lobes of the lung?
Posteriorly below rib 8– Left and Right
Laterally- below rib 5
Anteriorly- below rib 6
Apex -first intercostal space
Superior Lobes -Anterior above rib 4, posterior above rib 5
Middle Lobe Right – Anterior midclavicular line- ribs 4-6
How does parasympathetic stimulation of the lung affect the bronchioles and pulmonary arteries?
Effect of sympathetic stimulation (fibres are post-synaptic, their cell bodies are in the paravertebral sympathetic ganglia of the sympathetic trunks. :
- Inhibitory to the bronchial muscles= Bronchodilation
- Motor to pulmonary vessels =Vasoconstriction
- Inhibitory to the alveolar glands of the bronchial tree- type two secretory alveoli.
Effects of parasympathetic stimulation: (the parasympathetic fibres conveyed to the pulmonary plexus are presynaptic fibres from Vagus. They synapse with parasympathetic ganglion cells in the pulmonary plexus along the branches of the bronchial tree.
- Motor to the smooth muscle of the bronchial tree =Bronchoconstrictor
- Inhibitory to the pulmonary vessels = vasodilator
- Secretory to the glands of the bronchial tree = secretomotor
List the structures found in the mediastinum?
-Heart, oesophagus, proximal bronchial tree, thyroid, thymus, trachea
-Vessels – aorta, sup and inf vena cava, brachiocephalic veins, azygous veins, thoracic duct
-Nerves – cardiac plexus, phrenic, vagus, recurrent laryngeal, symp chains – Tx splanchnic nerves that go
to cardiac plexus
Superior mediastinum: contents “PVT Left BATTLE”
Phrenic nerve Vagus nerve Thoracic duct Left recurrent laryngeal nerve (not the right) Brachiocephalic veins Aortic arch (and its 3 branches) Thymus Trachea Lymph nodes Esophagus
