Lungs, Pleura and Ventilation Flashcards
Diaphragm: describe the attachments and relations of the diaphragm and the structures that pass through and behind it. Explain the movements of the diaphragm, its motor and sensory innervation and pleural and peritoneal coverings Ventilation: explain the movements involved in normal, vigorous and forced ventilation and describe the muscles responsible for these movements Lungs: demonstrate the surface markings of the pleura, lobes and fissures of the lungs and explain their clinical significan
What is the structure of the diaphragm?
Has a sheet-like central tendon with skeletal muscle radiating laterally to the costal margin (called the costal part of the diaphragm). The pericardial sac is found anteriorly. Has right and left dome – right dome is larger. The left and right crus are muscular extensions that firmly anchor the diaphragm to the vertebral column. Attached across the entire inferior thoracic aperture.
Where does the dome of the diaphragm bulge?
The dome (red line) bulges high inside the rib cage – so some high abdominal organs (enclosed partly in the rib cage) such as the liver, are covered by diaphragm, pleura and lung.
What does the diaphragm directly separate between the abdomen and thorax?
Left lung from left lobe of the liver, stomach and spleen. Right lung from right lobe of liver.
What does the diaphragm do in ventilation?
It is the main inspiratory muscle. Contraction of the diaphragm increases the vertical dimension of the thoracic cavity. When it contracts, the diaphragm presses on the abdominal viscera (meaning internal organs) which descends. Further descent is stopped by is stopped by the abdominal viscera, so more diaphragm contraction raises the costal margin. Increased thoracic capacity produced by diaphragm and rib movements in inspiration reduces intrapleural pressure, with entry of air through respiratory passages and expansion of the lungs.
Where do the contents of the mediastinum pierce the diaphragm?
Vena cava (8 letters) – T8. Through the central tendon. Oesophagus (10 letters) – T10. Through the costal region of the diaphragm (muscular). Descending aorta (12 letters) – T12. Through the costal region of the diaphragm (muscular).
How is the diaphragm innervated? What do these nerves do?
PHRENIC NERVES. Motor nerves to the diaphragm – C3, 4, 5 keep the diaphragm alive. So is parasympathetic. They are also sensory to the central tendon of the diaphragm, and peritoneum of central diaphragm.
What is the position of the trachea?
Extends from vertebral level C6 to T4/5.
What is the anatomy of the trachea?
Held open by C-shaped cartilage rings (the cartilage ring opens posteriorly at the oesophagus – see photo!), lowest cartilaginous ring is a hook called a carina (which is in line with the sternal angle) that creates ridge between the left and right bronchus as the trachea bifurcates (like the keel of a ship). Below this is a cluster of lymph nodes.
What is the position of the primary bronchi?
Formed at T4/5.
What is the anatomy of the primary bronchi?
Right wider and more vertical than the left because of the carina which is in line with the sternal angle – hence things are more likely to be lodged in this bronchus naturally.
What are the secondary bronchi?
Also called lobar bronchi. Formed within the lungs. Supply the lobes of the heart. 3 lobes in right, so 3 lobar bronchi. 2 lobes in left, so 2 lobar bronchi.
What are tertiary bronchi?
Also called segmental bronchi. Supply the bronchopulmonary segments – self-contained independent units of lung tissue.
What does the bronchial tree describe?
Branching pattern of trachea into main, lobar and segmental bronchi.
What is the structure of the larynx?
The cricothyroid ligament is a flat band of connective tissue. The conus elasticus are the lateral portions of this ligament. The cricothyroid ligament is what is pierced in a cricothyrotomy to access the airways.
What is the anatomy of the bronchopulmonary segments?
10 independent segments of each lung. So, even though there are different number of lobes in each lung, there are the same number of segments. They are the smallest, functionally independent regions of the lung – with own blood and air supply (each have a tertiary bronchi), such that they can be removed without affecting anything upstream!
What is position of the apex and base of the lungs in the thorax?
APEX: found at the thoracic inlet oblique, rising 3-4cm above level of first costal cartilage. BASE: concave, and rests on the convex surface of the diaphragm. It has 3 borders – anterior, posterior and inferior; and 3 surfaces – costal (ribs), medial (mediastinal), inferior (diaphragmatic).
What are the blood vessels that pass through the hilum called? (x4)
Bronchial arteries: supply oxygenated blood to the lungs. Bronchial veins: remove deoxygenated blood from the lungs. Pulmonary arteries: supply deoxygenated blood to the lungs to collect oxygen. Pulmonary veins: remove oxygenated blood from the lungs.
What is the anterior and posterior part of the lungs? What are they separated by?
Posterior part of the lung is in contact with the thoracic vertebrae (called paravertebral gutter) – The posterior part is notably thick because we are very front heavy, so it is like a counterbalance – shifts our centre of balance. Anterior part is deeply concave as it accommodates the heart. The cardiac impression is larger on the left than on the right because of the position of the heart. Anterior and posterior is separated by the blue line.
What is the structure of the left lung?
Two lungs. Superior (lies above fissure and contains the apex and MOST OF THE ANTERIOR PART OF THE LUNG) and inferior. Separated by oblique fissure.
What is the structure of the right lung?
Three lobes: superior, middle, inferior. Oblique fissure separates inferior lobe from the other 2 (same landmarks as in the left). Horizontal fissure separates superior from middle lobe. Note in the photo how different lobes are once again covering more of the anterior part of the lung than the posterior part.
What is the structure of the root of the lung (hilum)?
Contains primary bronchus (which bifurcates before/during entry), pulmonary artery, two pulmonary veins, bronchial arteries, bronchial veins, pulmonary plexus of nerves, lymph vessels and nodes. The lymph vessels and bronchial vessels are very small. Need to know arrangement. The photo shows the left lung. In the right lung, the bronchi are more superior and have bifurcated. The pulmonary arteries have also bifurcated and lie anterior to the bronchi. The pleural refection occurs at the hilum where the pulmonary ligament attaches to the lung. The pulmonary ligament is the pleural and visceral layer. Above the hilum in the right lung, the groove is of the azygous arch.
What is the anatomical region occupied by the inferior surface of the lung?
Inferior margin of the lungs travels around the thoracic wall following a VI, VIII, X contour i.e. rib VI in the mid-clavicular line, rib VIII in the midaxillary line, and vertebra TX posteriorly.
What is the surface anatomy of the oblique and horizontal fissures?
In the posterior view: the oblique fissure is located in the midline near the spine of vertebra TIII/TIV. It moves laterally in a downward direction, crossing the fourth and fifth intercostal spaces and reaches rib VI laterally. In the anterior view, the horizontal fissure (which is pretty anterior) on the right side follows the contour of rib IV and its costal cartilage to the mid-axillary line. The oblique fissures follow the contour of the rib IV and its costal cartilage.
What happens to the chest wall in ventilation?
Bucket handle movement – ribs move superiorly and anteriorly in a handle-like movement – swinging out anteriorly THEN superiorly – increases antero-posterior dimension of the thoracic cavity. At the same time, ribs are everted (turned outwards), increasing transverse diameter of thoracic cavity = lateral expansion. Internal and external intercostal muscles stiffen the rib cage to increase efficiency of the diaphragm.
What happens to the costal margin during the chest wall movement of inspiration?
Inspiration raises the costal margin which widens the pleural cavities by raising drooping lateral parts of the ribs. Raising costal margin also raises the anterior ends of the ribs, and tilting the sternum upwards to increase antero-posterior diameter of pleural cavities.
How are the lungs innervated?
Supplied by visceral afferents and efferents distributed through the ANTERIOR AND POSTERIOR PULMONARY PLEXUS. These lie anteriorly and posteriorly to the tracheal bifurcation. The branches of these plexuses ultimately originate from the sympathetic trunks AND vagus nerves. Visceral efferents from the vagus nerve constricts the bronchiole; efferents from the sympathetic trunk dilates the bronchioles.
How is the pleural cavity formed embryogenically?
Pleural cavities inside chest walls are lined by parietal pleura. Lung buds grow into the parietal pleura medio-laterally, within a covering of visceral pleura. The two pleural cavities are separated completely by the mediastinum.
What is the surface anatomy of the pleura?
Superiorly, the parietal pleura projects above the first costal cartilage above the medial 1/3 of the clavicle and the sternoclavicular joint.
Anteriorly, the costal pleura approaches the midline posterior to the upper portion of the sternum i.e. just behind the bone at the sternal angle.
Posteriorly the left parietal pleura does not come as close to the midline as it does on the right side because of the heart bulge on the left side. Parietal AND visceral stops moving posteriorly at the 6th CC (xiphoid process).
Inferiorly, the parietal pleura reflects onto the diaphragm and courses around the thoracic wall following an VIII, X, XII contour i.e. rib VIII in mid-clavicular line, rib X in midaxillary line, vertebra TXII posteriorly. The lung does not completely fill the area surrounded by the pleural cavities – the visceral pleura is found at the inferior margin of the lungs and travels around the thoracic wall following a VI, VIII, X contour i.e. rib VI in the mid-clavicular line, rib VIII in the midaxillary line, and vertebra TX posteriorly.
How is the lymphatic system of the lungs drained? Anatomical positions and route?
Tracheobronchial nodes. Found around the bronchi and trachea. From within the lung, so emerge through the hilum. Unite with vessels from parasternal and brachiocephalic nodes, anterior to brachiocephalic veins. These drain into the brachiomediastinal trunks (left and right).
What is the anatomy of the lymphatic system of the lungs? Pathological relevance of one?
ONLY NEED TO KNOW BRIEFLY. Enlargement of the inferior tracheobronchial (carinal) nodes causes a change in the SUB-CARINAL angle – so used pathologically to indicate possibility of lung cancer.
