Midterm Flashcards
force that occurs as the result of lungs and body wall (ribs and intercostal muscles) constantly trying to pull away from one another
intrapleural pressure - ALWAYS negative
alveolar pressure starts out as equal to atmospheric (0 cm H2) and as the lungs increase in size, what happens to alveolar pressure?
decreases (to about -1 cm H2O) allowing air to flow into the lungs
amount of air you inhale and exhale at rest is referred to as what (~500 mL)
tidal volume
places where the airway does not contain alveoli (thus blood cannot pick up oxygen here)
anatomic dead space
what is the equation for alveolar ventilation
VdotA= (Vt-Vds) * f = (tidal volume- dead space) * frequency
how much air is inhaled every minute
minute ventilation
what is the name for the protective covering of the lungs
pleura (visceral and parietal)
what is the intrapleural pressure of the lungs relative to atmospheric pressure
below atmospheric pressure
what is the intrapleural pressure of the lungs relative to atmospheric pressure while the lungs are at rest
below atmospheric pressure (about -5 cm H2O)
as the thorax increases in volume during inspiration what happens to intrapleural pressure
decreases (to -8 cm H2O)
what muscles are involved in forceful exhalation
abdominals, internal intercostals
what muscles do we use to exhale when we are breathing normally
NONE- expiration is passive
what muscles do we use to exhale when we are breathing normally
NONE- expiration is passive
what happens to alveoli when alveolar pressure drops below atmospheric pressure
air flows into the lungs
how do you calculate minute ventilation? (Vdot)
Vdot= Vt * freq
When is alveolar pressure equal to atmospheric pressure in the respiratory cycle?
In between inhalation and exhalation
When is alveolar pressure at its maximum in the respiratory cycle?
Mid-exhalation
When is alveolar pressure at its minimum in the respiratory cycle?
Mid-inhalation
When is intrapleural pressure at its minimum in the respiratory cycle?
After inhalation
When is intrapleural pressure at its maximum in the respiratory cycle?
After exhalation
what are the boundaries of the thorax
ribs, vertebra, superior thoracic aperture (thoracic inlet), diaphragm
we can divide the thorax into what 3 compartments
2 pulmonary cavities and 1 mediastinum
what are the 3 parts of the sternum
manubrium, body of sternum, typhoid process
how many costal notches do you find on the sternum
7