Pulmonary- anatomy, mechanics of breathing, and ventilation Flashcards
Borders of the bony thorax: anterior border- sternum
- lateral borders of trachea run perpendicular into suprasternal notch
- angle of Louis (sternal angle)bony ridge between manubrium and body,point of ant. attachment of 2nd rib and tracheal bifurcation
Borders of the bony thorax: lateral- rib cage
- ribs 1-6 (true ribs or costosternal ribs) have single ant. costochondral attachment to sternum
- ribs 7-10 (false ribs or costochondral ribs) share costochondral attachments before attaching ant. to sternum
- ribs 11-12 (floating ribs or costovertebral ribs) have no ant. attachment
Borders of the bony thorax: Posterior
vertebral column T1-T12
Borders of the bony thorax: shoulder girdle
- can affect the motion of the thorax
- provides attachments for accessory muscles of ventilation
Internal structures: upper airways
- nose or mouth: entry point. nose filters, humidifies, and warms air
- pharynx: common area used for both respiratory and digestive systems
- larynx: connects the pharynx to trachea, including the epiglottis and vocal chords
Internal structures: lower airways
- the conducting airways, trachea to terminal bronchioles, transport air only.
- the respiratory unit: respiratory bronchioles, alveolar ducts, alveolar sacs, and alveoli. Diffusion of gas occurs through all of these structures
Internal structures: lung structures
- R lung: 3 lobes divided by horizontal and oblique fissures, Each lobes divides into a total of 10 segments
- L lung: 2 lobes divided by oblique fissure line, total of 8 segments
Internal structures: pleura
- parietal pleura: covers inner surface of thoracic cage, diaphragm, and mediastinal border of the lung
- visceral pleura: wraps the outer surface of the lung, including the fissure lines
- intrapleural space- the potential space between the 2 pleurae that maintains the approximation of the rib cage and lungs, allowing forces to be transmitted from one structure to another
Muscles of Ventilation: primary muscles of inspiration
- produce a normal resting tidal volume
- diaphragm: made of 2 hemidiaphragms, each w/ a central tendon. When the diaphragm is at rest, the hemidiaphragms are arched high into the thorax, When contracting, the central tendon is pulled downward, flattening the dome, resulting n protrusion of the abdominal wall.
- additional primary muscles of inspiration are portions of the intercostals
Muscles of Ventilation: accessory muscles of inspiration
- used when a more rapid or deeper inhalation is required or in disease states
- scalenes and SCM raise upper 2 ribs
- levator costarum and serratus raise remaining ribs
- trapezius, pecs, and serratus can become muscles of inspiration by fixing the shoulder girdle
Muscles of Ventilation: expiratory muscles of ventilation
- resting exhalation is passive relaxation of inspiratory muscles and elastic recoil of lung. Normal abdominal tone holds abdominal contents below diaphragm, assisting return of diaphragm to dome position.
- Quadratus lumbrum, portions of intercostals, muscles of the abdomen, and triangularis sterni: expiratory muscles used when quicker and/or fuller expiration is desired (exercise or disease states)
Muscles of Ventilation: patients who lack abdominal musculature (ex: SCI)
- have a lower resting position if the diaphragm, decreasing inspiratory reserve
- the more upright the body position, the lower the diaphragm and the lower the inspiratory capacity
- the more supine the body position, the more advantageous the position of the diaphragm
- abdominal binders may be helpful for support of abdominal viscera, assisting ventilation. Do not constrict bony thorax w/ binder.
Mechanics of breathing: forces acting on rib cage- elastic recoil of lung parenchyma
pulls lungs and therefore visceral pleura, parietal pleura, and bony thorax into a position of exhalation (inward pull)
Mechanics of breathing: forces acting on rib cage- the bony thorax
it pulls the thorax, and therefore parietal pleura, visceral pleura, and lungs into a position of inspiration (outward pull)
Mechanics of breathing: forces acting on rib cage- muscle action
pulls either outward or inward, depending on muscles used
