LUNG ANATOMY Flashcards
Where is the superior thoracic aperture located?
Posteriorly to T1 and laterally to 1st pair of ribs, anteriorly to superior border of manubrium
Where is the inferior thoracic aperture located?
Posteriorly to T12, posterio-laterally to 11th/12th pair of ribs, anterior-laterally to continuous costal cartilages of ribs 7-10, anteriorly xiphisternal joint, inferiorly to the diaphragm
Movements of rib cage
During forced respiration, the rib cage will elevate and widen to increase the inspiration volume
External intercostal muscles are most active during inspiration
Internal intercostal muscles are active during expiration
What does the sternum consist of?
Manubrium, body and xiphoid process
Which ribs are attached to the sternum?
1-7
What blood supply to the alveoli is from the pulmonary veins and arteries?
From the heart:
Deoxygenated blood from the right ventricle enters the pulmonary artery
Oxygenated blood from the pulmonary vein flows into the left ventricle.
How does venous drainage of thoracic wall occur?
This occurs mostly through the azygos veins
They are posterior of the IVC
How many lobes does the right lung have?
3 (upper, middle, lower)
How many lobes does the left lung have?
2 (upper, lower)
What are the lobes separated by?
Oblique fissures (also horizontal fissure on the right)
Where is the trachea located?
Superior of the thorax, inferior of the larynx
Where does the trachea bifurate?
Carina
What does the trachea separate into?
Left and right main bronchus and enter the lung at the hilum
Each main bronchus separates into lobular bronchi
Each lobular bronchi separate into segmental bronchi
What is the trachea and bronchi composed of?
16-20 incomplete rings of hyaline cartilage
Incomplete posteriorly as in contact with oesophagus so accommodates swallowing
Cartilaginous rings prevent the trachea from collapsing
What is the trachea and bronchi lined with?
Ciliated columnar epithelium and goblet cells
What are the lungs lined by?
Visceral pleura and the parietal pleura
What is inside the pleural cavity?
Serous pleural fluid - allows 2 layers to slide over eachother during respiration
Each bronchiole is formed of what?
2-11 alveolar ducts with 5-6 alveolar sacs
Respiratory zone is not ciliated, debris is removed by macrophages
What are the alveolar sacs surrounded by?
Elastic fibres
Expand during inhalation
Recoil during expiration
Type I pneumocyte
simple squamous cell – thin to enable gas exchange
Type II pneumocyte
secretory cell to produce surfactant.
Surfactant
Decreases surface tension to stop collapse at the end of expiration
How much does diaphragm move in quiet respiration vs expertise conditions?
1cm and 10cm
Pulmonary ventilation-exhalation
Diaphragm moves up + intercostal muscles relax:
reduces lung volume,
pressure in the lungs greater than outside.
Air pushed out of lungs to the area of lower pressure.
Accessory muscles during forced expiration
What percentage of air intake reaches alveoli and what percentage stays in the airways?
70% vs 30%
Bronchiodilation is done by?
Sympathetic nervous system
Bronchoconstriction is done by?
Vagus nerve
What happens in an individual with asthma?
Bronchiolar smooth muscle contracts and thick secretions narrowing the airway, restricting airflow to alveoli
Signs and symptoms of asthma?
Severe dyspnoea
Wheezing
Acute respiratory failure, hypoxia and death are possible
What is the primary cause of COPD?
Smoking
What does COPD stand for?
Chronic obstructive pulmonary disorder
Diagnosis of COPD
Clinical examination
Barrel chest
Lung function tests
Treatment of COPD
Psychosocial interventions
Bronchodilators
What side does congestive heart failure occur?
Left
What is Atelectasis?
Obstruction of the bronchus.
As the air behind the obstruction is absorbed into the pulmonary blood supply,
the lung behind the obstruction collapses,
Fluid from the pleural space fills the gap.
can be segmental, lobular or affect the entire lung.
What is plural effusion?
Caused by an excess of pleural fluid which eventually collapses the lung.
Heart failure, infection or even physiological mechanisms triggered by the tumour itself.
