Mechanisms of ventilation Flashcards
(33 cards)
What is the upper tract of the respiratory system
nasal cavity, pharynx, larynx
What is the lower tract of the respiratory system
trachea downwards
What keeps the trachea open at all times
rings of cartilage
Right lung structure
3 lobes: superior, middle, inferior
2 fissures: horizontal, oblique
Left lung structure
2 lobes: superior, inferior
1 fissure: oblique
Difference between right and left bronchus
left is shorter, more horizontal and wider
Respiratory tract from nose to trachea
nasal cavity superior an dinferior concha opening of pharyngotympanic tube Pharynx: naso, oro, laryngo epiglottis larynx trachea (oesophagus)
Epiglottis role
covers the laryngeal inlet so food passes into the oesophagus and not the trachea
How do we breathe?
diaphragm contracts and flattens, increasing thoracic volume and decreasing pressure
air is drawn into the lungs from outside
air passes into terminal bronchioles/alveoli to oxygenate blood
diaphragm relaxes, lungs recoil, thoracic volume decreases, intrathoracic pressure increases and air expelled
What is the most important muscle in respiration?
diaphragm
What innervates the diaphragm?
phrenic nerve (C3-5)
Attachments of diaphragm
anterior: xiphisternum and costal margin
lateral: ribs 6-12
posterior: T12
Accessory muscles of respiration
intercostal muscles sternocleidomastoid scalenus anterior pecs trapezius
How do the icms assist respiration?
contraction of obliquely angled external and internal fibres raises each rib toward the rib above to rasie ribcage
innermost and inner depresses each rib to the rib below, lowering the rib cage
How does the sternocleidomastoid muscle assist respiration?
attaches to manubrium and clavicle and mastoid process on the skull
raises sternum
How does scalenus anterior assist respiration?
prevent rib 1 and 2 from descending
How does do the pecs and trapezius assist respiration?
fix the pectoral girdle to raise rib cage
Movement of the ribs and sternum when breathing
sternum: pump
ribs: bucket handle
lower ribs expand ribcage most for sternum to move
Where are the apex of the lungs and what are they covered by?
above 1st rib
covered by suprapleural membrane (so lungs don’t dip in and out of neck)
What allows the thoracic cavity and lungs to expand?
surface tension between the parietal and visceral pleura
Difference between adults and babies breathing
babies can only breathe via abdominal breathing
newborn ribs more horizontal - no pump/bucket movement
weak icms, use only diaphragm
Dangers of relying on the diaphragm for breathing
high risk for respiratory failure if it is unable to contract
Difference between adults and children breathing
nasal breathers until 4-6 wks shorter neck and narrower airways larger tongue smaller lung capacity, underdeveloped chest muscles higher respiratory rate
Dangers of breathing as a child
narrower airways: more susceptible to blocked airways and respiratory distress
larger tongue: obstruct when unconscious