lungs anatomy Flashcards
What are the parts of the pleurae?
- Parietal pluera:
Cervical,
Mediastinal,
Costal,
Diaphragmatic - Visceral pleura: adherent to lungs
- Continuity btw parietal & visceral gives pulmonary ligament
- Pleural cavity: potential space containing pleural fluid
- Pleural fluid: lubricates pleural layers allowing sliding as lung inflates,
plus surface tension of fluid allows cohesion of lung surface to thoracic wall
=> ensures that lungs follow chest movements during breathing
What are the pleural recesses and what is their significance?
- Costodiaphragmatic recess: where costal & diaphragmatic pleura meet,
at inferior border of lungs - Costomediastinal recess: where costal & mediastinal pleura meet, at anterior border of lungs
Recesses form as lungs do not fully occupy pulmonary cavities during expiration
=> allow for expansion of lungs during inspiration
What is the structure of the bronchial tree?
1. Trachea forms from larynx at (…), supported by (…)
2. At (…), trachea bifurcates into right & left (…)
3. (…) separates the 2 main bronchi,
and is sensitive, triggers cough reflex
4. Primary (main) bronchi divide into (…), each supplying a lobe
5. Secondary (lobar) bronchi divide into (…)
6. Further division into conducting bronchioles, terminal bronchioles, respiratory bronchioles, alveolar ducts, alveoli
- Trachea forms from larynx at C6, supported by C-shaped rings of hyaline cartilage
- At sternal angle (T4), trachea bifurcates into right & left primary (main) bronchi
-
Carina separates the 2 main bronchi,
and is sensitive, triggers cough reflex - Primary (main) bronchi divide into secondary (lobar) bronchi, each supplying a lobe
- Secondary (lobar) bronchi divide into tertiary segmental bronchi
- Further division into conducting bronchioles, terminal bronchioles, respiratory bronchioles, alveolar ducts, alveoli
When foreign objects are aspirated into lungs, where are they more likely to enter?
Right main bronchus
as it is shorter and more vertical
What is a bronchoscopy?
Allows viewing of tracheobronchial tree
What are bronchopulmonary segments?
- 18-20 pyramidal-shaped subdivisions of a lobe, apices facing root of lung, bases at pleural surface
- Each supplied by tertiary segmental bronchi and tertiary branch of pulmonary artery
- Venous drainage not by specific vein
- Surgically resectable when tumours localise in 1 segment
3 surfaces
What are the surfaces of the lungs?
- Costal
- Mediastinal
- Diaphragmatic
defined by the structures they face
What are the borders of the lungs?
- Anterior
- Inferior
- Posterior
serve as transitions between surfaces
Where is the apex and base of the lungs?
- Apex: extends into root of neck
- Base: rests on diaphragm
What are the unique features of the left lung?
-
Deep cardiac notch
to make room for heart
which is more to the left side of the chest - Lingula (tongue-shaped process)
-> compensates for lack of middle lobe
What is the structure of the right lung?
- 3 lobes
(superior, middle, inferior) - Oblique fissure
- Horizontal fissure
What is the structure of the left lung?
- 2 lobes
(superior, inferior) - Oblique fissure
What is the pulmonary blood supply?
-
2 pulmonary arteries which divide to form
→ lobar arteries
→ tertiary segmental arteries - 4 pulmonary veins
What are the pulmonary lymphatics? - Tracheobronchial nodes surround roots of main & lobar bronchi
tracheal sides - Efferent vessels from tracheobronchial
parasternal
brachiocephalic nodes join to form bronchiomediastinal trunks - Bronchiomediastinal trunks drain into thoracic duct (L side) & right lymphatic duct (R side) - Bronchopulmonary (hilar) nodes at hilum of lung
How does a lung carcinoma affect the diaphragm? Lung carcinoma leads to swelling of supraclavicular lymph nodes
may affect phrenic nerve
paralyse diaphragm
What are the bronchial vessels? - Bronchial arteries - Bronchial veins - Drain directly into left atrium
creating a physiological shunt
diluting oxygenated blood of aorta
What is the neurovascular supply of the pleurae? Parietal pleura: supplied by nerves & vessels that supply cutaneous layer - Pain may be local or referred to same spinal dermatome Visceral pleura: supplied by nerves & vessels that supply viscera - Pain may be referred to C3-5 (shoulder & root of neck)
What is the autonomic nervous supply to the lungs?
What are the features labelled in the diagram? L: Lung R: Rib T: Trachea AK: Aortic knob A: Ascending aorta H: Heart (on LHS) P: Pulmonary artery S: Spleen Li: Liver (breast shadows may be vis)
What is the condition present in this X-ray?
Pneumothorax in R lung
- Collapsed lung (atelectatic)
- Air appears black
- No vascular markings
<- sign of collapsed lung
(and indicates NOT fully expanded lung)
as vascular markings are typically visible along lung parenchyma
- Deep sulcus (larger costodiaphragmatic recess)
due to accumulation of air pushing lung away from diaphragm
- Increased haziness on L lung
due to diversion of entire cardiac output
-> increased blood vol and thus vascular distension (i.e. increased diameter)
of blood vessels of L lung
What is a pneumothorax?
Air in pleural cavity
What is a hemothorax?
Blood in pleural cavity
What is a tension pneumothorax? Punctured skin & fascia forms a one-way valve
allowing air in but not out → thoracic pressure increases → compresses mediastinal structures
affects cardiovascular function Clinical symptoms: - Trachea shifted to side - Elevated JVP
What is the condition present in this X-ray?
Pneumonia
- Density in right upper lobe
<- consolidation (fluid, pus or inflammatory cells filling the alveoli)
- Horizontal fissure not shifted
-> indicates lack of large consolidation or lung collapse
bcos in those cases lung tissue shrinks
and pull fissure upward
SImilar to CXR findings for heart failure
B: 1
C: 1
D: 2
What is the condition present in this X-ray?
Pulmonary edema
- Bilateral pleural effusions (loss of sharp costodiaphragmatic recess)
- Cardiomegaly
- Upper lobe Diversion (thick vascular lines)
where blood is diverted to upper lobes due to increased pulmonary venous pressure
and fluid in lower zone
-> impair gas exchange
-> alveolar hypoxia
-> arteriolar vasoconstriction
- Interstitial/alveolar oeDema
(for interstitial, interstitial markings)
What is the condition present in this X-ray?
Hyperinflated chest (eg due to COPD)
- Ribs very horizontal (increased ant-pos diameter)
(often described as “barrel chest”)
- 10 ribs visible (normal 8-9)
other usual findings:
* hyperlucency (darker areas)
due to increased vol of air in lungs
* flattened diaphragm
due to force exerted by trapped air
What is the condition present in this X-ray?
Atelectasis of R lung
- Loss of air in alveoli
- Collapse of R lung
<- lung tissue becomes denser as there is now less air and more tissue
differences from collapsed lung in pneumothorax
* localised opacity (white area)
* mediastinum shifts towards collapse
as there is now a decrease in lung vol
-> less pressure exerted on mediastinum
What is atelectasis? Loss of air in alveoli Multiple causes: - Airways obstructed
blood flow continues and absorbs all O2 & N2 - Loss of surfactant - Loss of negative pleural pressure Note: pneumothorax features atelectasis but not synonymous
When do different parts of lungs mature?
- Lungs remain collapsed until birth
- Mature alveoli may not form until after birth
- Type 2 pneumocytes only mature and produce surfactant towards end of pregnancy
What is respiratory distress syndrome? - Premature infants often lack sufficient surfactant for adequate lung inflation - Maternal glucocorticoid treatment used to prevent RDS in preterm labour
What are the embryological components of the diaphragm? - Diaphragm develops form mesoderm - Central tendon: forms from septum transversum (mesoderm) which forms cranial to pericardial cavity
later lies between pericardial & abdominal cavities after cephalocaudal folding - Right/left crus (muscle): dorsal mesentry of esophagus (connects gut to back) - Musculature: develops from somites C3-C5 - Plueroperitonial membranes: close the left and right pleuroperitonial canal
form connective tissues around central tendon - Form large portions of early fetal diaphragm
only small portions of newborn diaphragm
What are the relations of the root/hilum of the lungs?
What is the suprapleural membrane? - Sibson’s fascia - Attached to: - C7 transverse process - 1st rib & costal cartilage - Mediastinal pleura
2 different parts
which parts of the sternum do the ribs connect to
- Ribs 1 and 2 connect to manubrium
- Ribs 2 to 10 (plus rib 2) connect to body,
but ribs 2-7 connect directly via costal cartilages,
while ribs 8 to 10 connect indirectly via costal cartilage of superior rib
(their costal cartilages fuse with costal cartilage of rib 7)
Ribs 11 and 12 do NOT connect to sternum at all
and what do they supply
which nerves and vessels are present in the thoracic outlet
i.e. bet clavicle and 1st rib
- subclavian artery and subclavian vein
=> provids vascular supply to shoulder and upper limbs - brachial plexus
=> nerves that supply fingers
what structures pass thorugh opening in diaphragm @ T8
Inferior vena cava
“vena cava (8 letters) passes through T8”
what structures pass thorugh opening in diaphragm @ T10
- oesophagus
- vagus nerve
“oesophagus (10 letters)
and vagus nerve (CN X)
passes through T10”
what structures pass thorugh opening in diaphragm @ T10
- Thoracic Aorta
- Thoracic duct
- Azygos vein
“Thoracic Aorta (13 letters, close to 12),
Thoracic duct and Azygos vein
passes through at T12”
