mechanics of breathing Flashcards
what is the purpose of respiration?
maintain an adequate oxygen level in the blood to support cellular life
is the mechanical act of breathing and is accomplished by expansion of the chest, both vertically and horizontally
external respiration or ventilation
accomplished through contraction of the diaphragm
vertical expansion
occurs as intercostal muscles lift the sternum and elevate the ribs, resulting in an increase in anteroposterior diameter
horizontal expansion
a slight negative pressure is created in the lungs in relation to the atmospheric pressure, resulting jn an inflow of air into the lungs
inspiration
mostly passive in nature and occurs with relaxation of the intercostal muscles and the diaphragm
expiration
change according to cellular demands often without awareness on the part of the individual
breathing patterns
the strongest stimulus to breath is an increase of carbon dioxide in the blood
hypercapnia
decrease in oxygen
hypoxemia
also increases respiration but is less effective than a rise in carbon dioxide level
hypoxemia
during ____ the diaphragm presses the abdominal organs downward and forward
inhalation
during ____ the diaphragm ruses and recoils to the resting position
exhalation
difficulty breathing
dyspnea
____ onset of dyspnea is usually indicative of lung changes such as emphysema
gradual
____ onset is associated with viral or bacterial infections, acute asthma exacerbation, acute myocardial ischemia/ infarction, pulmonary embolism
sudden onset
