Structure of The Airway Flashcards
What structures form the conducting part of the respiratory tract? (6)
nasal cavity, pharynx, larynx, trachea, bronchi, bronchioles
What structures form the respiratory part of the respiratory tract?
respiratory bronchioles, alveolar ducts, alveoli
What are the structures of the nasal cavity? (5)
nose, septum, lateral walls with conchae, meats, airway
Where is entry into the nasal cavity?
the nares
What holds open the nasal cavity?
bone and cartilage
Where is the nasal cavity found?
above the oral cavity, between the two orbits, posterior to the nose and anterior to the nasopharynx
What is the nasal cavity lined with including the type of cells?
- highly vascularised mucosal membrane lined with respiratory epithelium
- pseudo stratifies ciliated columnar interspersed with goblet cells (secrete mucus)
What is the nasal septum?
midline structure that separates right and left nasal cavities
made of septal cartilage (anterior part) and bone (posterior part)
What are the nasal conchae (turbinate)?
curved shelves of bone found on the lateral wall of the nasal cavity
there are three - superior, middle, inferior
they provide turbulence and increase the surface area for air flow and heat exchange
What are the nasal meatus/?
nasal passage of the nasal cavity under/lateral to each concha (superior, middle , inferior)
What are the function of sinuses?
- lighten the skull
- produce mucus that moisturises the inside of the nose - assist in warming air - clearance of mucus is dependent on ciliary action
What are the 4 main sinuses?
- frontal
- sphenoid
- ethmoid
- maxillary
What are the three parts of the pharynx?
- nasal cavity (nasopharynx)
- oral cavity (oropharynx)
- larynx (laryngopharynx)
What is the function of the nasal cavity (nasopharynx)?
transport air - warm, moisturise and filter before air reaches lungs
What is the function of the oral cavity? (oropharynx)
transports air, food and fluid
- operated by epiglottis
What is the function of the larynx?
- allows air to pass without letting food block the airway
- contains the vocal cords
What is the structure of the larynx?
- members tube suspended between cartilages
- controlled by muscles
- diameter may be altered to allow the passage of air only - speech and raising into-abdominal pressure
- aryepiglottic fold forms the laryngeal inlet which is the protective sphincter
Where is the trachea?
- anterior to oesophagus
- medial to carotid arteries and internal jugular veins
- inferior to larynx
- thyroid glands surround upper portion
Describe the structure of the trachea?
c-shaped rings of cartilage supporting a fibro-elastic and muscular air-transport tube
- tracheal muscle (posteriorly positioned) can alter the tracheal diameter
What is the function of the trachea?
connects the larynx to the bronchi - for airflow
What is the position of the trachea?
palpable anteriorly above suprasternal notch
- starts at C6 and ends at T4/5
Explain the bronchi?
- each lung has one main bronchus (even though right lung has 3 lobes and left lung has 2)
- left lung has two lobar (secondary) bronchi - left superior lobar bronchus and left inferior lobar bronchus
- right lung has three lobar bronchi - right superior, right middle, right lower
- each lobar bronchi then divides into segmental bronchi
How do bronchi divide into bronchioles?
bronchi > conducting bronchioles > terminal bronchioles > respiratory bronchioles > aveoli
What supplies the bronchi with oxygenated blood?
bronchial arteries
What epithelium is present in the trachea?
pseudostratified ciliated columnar with goblet cells
What epithelium is present in the bronchi?
pseudostratified ciliated columnar - but cells are more flattened than in trachea
What epithelium is present in the bronchiole?
ciliated columnar - flatter than bronchi
What epithelium is present in the terminal and respiratory bronchioles?
non-ciliated cuboidal - thinner than in bronchioles - no goblet cells
What allows the alveoli to be good at gas exchange?
- thin membrane containing capillaries
- high surface area
What are the pleura?
a pair of membranes which line the thorax (cavity walls) and lungs - one continuous membrane
What is the pleural cavity?
space between the layers of pleura
- it contains fluid to libricate the pleural surfaces allowing for smooth, gliding movements during breathing
What is the visceral/pulmonary pleura?
pleura covering the lungs
What contributes to easy inflation of the lungs?
- slightly negative pressure in the pleural cavity
- lung is highly elastic - and partially inflated - so like a balloon less energy is required to inflate
What are the parietal pleura? name them
membranes which cover the cavity walls - depending on where the pleura is located a different name is used
- cervical, costal, mediastinal, diaphragmatic
Where does the cervical pleura lie?
?
Where does the costal pleura lie?
?
Where does the mediastinal pleura lie?
?
Where does the diaphragmatic pleura lie?
?
What happens if air gets into the parietal layer?
lung collapses due to loss of negative pressure - pneumothorax - air removed by inserting needle
What separates the two lungs?
mediastinum
Describe the structure of the left lung?
- slightly longer and narrower than the right lung
- two lobes - superior and inferior
- cardiac notch
- lingula
- oblique fissure
- apex and base
- hilum
What is the hilum?
“root of the lung”
- structures pass into and out of the lung - main bronchus, pulmonary artery, pulmonary veins)
What do the pulmonary arteries carry?
deoxygenated blood from the heart to lungs
What do the pulmonary veins carry?
oxygenated blood from the lungs to heart
Explain lung lymph drainage?
via a sub-pleural plexus and
plexus alongside the bronchi to the hilarity nodes
Describe the structure of the right lung?
- slightly wider but shorter than left - due to right dome of diaphragm being higher on this side
- 3 lobes - superior, middle, inferior
- horizontal/transverse fissure and oblique fissure (lower one)
- apex and base
- hilum
Describe the surface anatomy of the lungs?
- apex of lung and pleura are above the clavicle
- the pleura extend down to the costal margin - but lungs end 2 rib spaces higher
- during normal/quite respiration lungs do not extend to the lower parts of the pleural cavity
Explain the mechanisms of respiration?
- inhalation must increase the diameters of the thorax to create a negative pressure - which sucks air into the lungs via the trachea and larynx
- diaphragmatic contraction causes its descent - increasing its vertical diameter
- rib elevation (uses intercostal muscles too) pushes the sternum up and forward, and the ribs outward to increase anteroposterior and lateral diameters
- exhalation is by muscle relaxation and elastic recoil - passive
What is the function of intercostal muscles?
expand the size of the thoracic cavity during respiration - raise the ribs and push sternum upwards
What do the internal intercostals do?
depress the ribs pulling them inferiority as in deep exhalation
What so the external intercostals do?
elevate and lift ribs in deep inhalation
Explain the structure of the diaphragm?
- muscular at periphery
- tendinous centrally
- left and right domes
- motor ans sensory suppled by the phrenic nerve (C3,4,5 keep it alive)
Explain the function of the diaphragm?
during inspiration the domes of the diaphragm descend causing negative intrathoracic pressure but raising ire-abdominal pressure
