Lecture 6: Lungs and pleura Flashcards
What are the divisions of the thoracic caivty?
- Right hemithorax (R lung) - Left hemithorax (L lung) - Mediastinum -> Heart and related structures
What lines the chest cavities?
Pluera! (also opportunity for pathologies
What are the pleura of the chest cavity?
Visceral pleura (outer surface lungs) Parietal pleura (Lining pulmonary cavity) ENDOTHORACIC FASCIA Pulmonary ligament
What is the endothoracic fascia?
- Adheres costal parietal pleura to thoracic wall - Continuous with fibrous supraplueral membrane
What is the pulmonary ligament?
Sleeve of pleura hanging down from lung root
What innervates the visceral pleura? whats its sensitivity to pain?
ANS - T1-4 sympathetic - Vagus (CN X) (Insensitive to pain, this is referred)
What innervates the parietal pleura? Whats its sensitivity to pain?
- Intercostal nerves - Phrenic nerve (C3-5 keeps the diaphragm alive) Sensitive to pain, localised pain
What keeps the diaphragm alive?
C3,4,5 keep the diaphragm alive
For the surface markings of pleura and lungs what are the landmarks in relation to?
The landmarks are in relation to the ribs not the vertebral level
What are some surface markings of the lungs?
Lungs (up in 2’s) (This is where the base is found depending on which angle you are on) - Midclavicular line rib 6 (Front) - Mid-axillary line rib 8 (Side) - Scapular line rib 10 (Back)
What are some surface markings of the pleura?
Pluera (up in 2’s) (This is where the pleura base should be depending on what angle you are on) - Mid-clavicular line rib 8 (Front) - Mid axillary line rib 10 (Side) - Scapular line rib 12 (Back)
What are the recesses of the lung and what does this mean?
- Costodiaphragmatic recesses (Post-lower ribs) - Costomediastinal recesses These are potential spaces…
Discuss the importance of the costodiaphragmatic recesses;
- A potential space filled on inhalation - Fluid can accumulate and blunt the costodiaphragmatic angle // prevent lung expansion
What are the lobes and fissures of the left lung?
- Sup and inf. lobes - Oblique fissure
What are the lobes and fissures of the right lung?
- Sup, middle and inferior lobes - Oblique and transverse fissures
Whats of note about fissures?
They can fuse with age but remain functionally seperate
Describe the surfaces of the lung
Describe the bronchopulmonary segmentation beginning with the trachea;
Trachea -> Main bronchi -> Lobar bronchi -> Segmental bronchi (x10)
At what level is the carina found?
T4/5 // transthoracic plane
What is of notable difference between the main bronchi?
Different angles // right is larger and aspiration pneumonia is more common here, it is also on a different angle
What are the ANS pulmonary plexuses?
There are: - ANT and POST plexus around carina, post larger Comprised of Parasymp (VAGUS) and Symp (T2-4) (Thoracic ganglia)
What are the somatic plexus of the pulmonary space? and what do they do>
- Intercostals = Pain in body wall and parietal pleura = Motor to intercostals - Phrenics (C3-5) = Diaphragm control (mixture of ANS and Somatic b/c can occur autonomically and consciously)
What are the notable lymphatics of the lungs?
1) Paratracheal nodes 2) Thoracic duct and right lymphatic duct 3) (Bronchopulmonary) hilar nodes 4) Carinal nodes
Where does chest / lung pain present?
Phrenic nerve = C3-5 dermatome Intercostals nn = Specifically localised ANS T1-4 = Referred to T1-4 dermatomes T4 = nipples
Describe the flow of blood through the lungs from the heart, commenting on blood oxygenation;
Deoxygenated blood leaves right ventricle -> Pulmonary trunk -> Pulmonary arteries (x2) = Oxygenated in lung tissues -> Pulmonary veins (x4) -> Into left atrium and onto systemic circulation
What supplies the lung tissues with blood and nutrients?
Bronchial arteries (x2 LHS and x1 RHS) Come off aorta…
Whats of note about the anatomical route of the left main bronchus?
It crosses 3 structures
What are bronchopulmonary segments?
10 segments per lung - Smallest functionally independant region of a lung Each segment has; - A segmental bronchus - A pulm. artery - Bronchial art. branch Veins and lymphatics can be seen along edge of these segments Separated by thin CT
What happens in a patient with a patent ductus arteriosus?
Blood travels from aorta -> ductus arteriosus -> pulmonary trunk -> Lungs Depending on patency size - Can increase BF to lungs = pulm. hypertension / oedema - Decrease systemic blood flow = organ damage - Increase heart work
What can a patent foramen ovale lead to?
- Potentially silent (~25%) BUT could lead to; - Lower than normal O2 levels in arterial blood - Pulm. hypertension (Thicking of pulm art. -> RHS hypertrophy -> HF or reversal of patency flow and cyanosis)
What are the unique features of the fetal bypass system?
Lungs filled with fluid therefore pulmonary circulation has high resistance, in addition to; - Ductus arteriosus which redirects pulmonary trunk blood to the aorta - Foramen ovale which shunts blood from RA -> LA - Blood is oxygenated in the placenta, this returning blood drives straight to the LA to give highly oxygenated blood to the head. - Returning deoxygenated blood from the legs flows into the RA->RV - Some mixing of blood occurs in the aorta b/c of the ductus arteriosus
