Lungs Flashcards
Where is the trachea found?
Above the suprasternal notch starting at C6 and ending at T4/5
What is the trachea?
C-shaped rings of hyaline cartilage that hold the trachea open that support a muscular and fibro-elastic air-transport tube
What alters the tracheal diameter?
Trachealis muscle
How many lobes does the left lung have?
2
How many lobes does the right lung have?
3
What is the difference in composition of the right bronchus to the left bronchus?
The right bronchus is more vertical, shorter and wider
What is the consequence of the difference in shape of the right bronchus to the left?
Foreign bodies are more likely to enter the right lung
What supplies the bronchi with oxygenated blood?
Bronchial arteries
What are the names of the different lung lobes?
Right superior lobar bronchus Right middle lobar bronchus Right inferior lobar bronchus Left superior lobar bronchus Left inferior lobar bronchus
What can lobar bronchi be divided into?
Segmental bronchi
Describe the continuation of bronchi to form alveoli
Bronchi divide into smaller branches becoming conducting bronchioles then terminal bronchioles and respiratory bronchioles continually decreasing in diameter before forming alveoli
Describe the histology of the trachea
Pseudostratified, ciliated, columnar epithelia with goblet cells that secrete mucus
Describe the histology of the bronchi
Pseudostratified, ciliated, columnar epithelia but decreased in size compared to trachea and contains cartilage plates
Explain the composition of the bronchiole
Very thin lumen. Epithelium changes to become ciliated columnar and there is a surrounding band of smooth muscle, cartilage and glands disappear and the bronchiole is held open by surrounding lung tissue
Explain how asthma works in relation to the bronchiole
The smooth muscle in the bronchiole wall may excessively narrow the lumen
Explain the histology of the terminal and respiratory bronchioles
The epithelium becomes non-ciliated, cubiodal and the goblet cells disappear. Alveoli bud off from respiratory bronchioles and gas exchange begins to occur
Where are alveoli found?
Outpocketings of respiratory bronchioles, alveolar ducts and alveolar sacs
What separates alveoli?
Septae which is a thin membrane containing capillaries, it is the air-blood barrier for gas-exchange
What are pleura?
The membrane that lines the lungs within the cavity and the cavity walls
What is the pleural cavity?
Space between layers of pleura. Contains fluid that lubricates the pleural surfaces to allow friction free movement between surfaces
What is visceral pleura?
Pleura covering the lungs
What is parietal pleura?
Pleura covering the cavity walls
What separates lungs?
Mediastinum
Explain lung lymph drainage
Occurs by the sub-pleural plexus and a plexus alongside the bronchi to hilar lymph nodes
What is the hilum?
The root of the lung where structures pass into and out of the lung
Explain blood flow in the lungs
Deoxygenated blood enters the lungs via pulmonary arteries and oxygenated blood leaves via pulmonary veins
Explain the surface anatomy of the lungs
Superiorly, the lungs and pleura sit above the clavicle
Inferiorly, the lungs extend down the costal margin but end 2 ribs higher
Purpose of internal intercostal muscle?
Depress the ribs pulling them down in deep exhalation
Purpose of external intercostal muscle?
Elevate and lift ribs in deep inhalation which assists expansion of thoracic cavity
What is the anatomy of the diaphragm?
Muscular periphery and tendinous centrally, has 2 domes
What supplies the diaphragm motorally and sensorally?
The phrenic nerve C3,4,5
What occurs in the diaphragm domes during inhalation?
The domes descend causing negative intra-thoracic pressure but raising intra-abdominal pressure
What happens during a pneumothorax?
When air enters into the pleural cavity
What must be done to resolve a pneumothorax?
Air must be removed to allow the lung to expand again. a needle is inserted just above the rib to avoid damage to the neurovascular bundle that runs inferior to each rib.
