phagocytosis, inhibition of tumors, manufacture of interferon
Volume of air that is inhaled or exhaled during quiet breathing AVERAGE IS 500 mL (+/- 100 mL)
Total amount of air moved in or out for one minute
Forced Vital Capacity
deep breath in and blow out as hard and fast as you can
Peak Expiratory Flow
maximum flow at which a patient can exhale during a forced exhalation. Expressed as L/sec or LPM
that portion of ventilation that does not participate in gas exchange - wasted ventilation. (Ventilation without Perfusion)
volume in the conducting airways, including nose, [harynx, etc. AVERAGE IS 1 mL/Lb OF BODY WEIGHT!
PErfusion without ventilation
that portion of gas available for gas exchange.
volume of gas that ventilates unperfused alveoli. If this becomes high, usually indication of pathologic state like a pulmonary embolus
sum of the anatomic and alveolar deadspace. Total amount of wasted ventilation NORMAL IS 20%-40% OF TOTAL VENTILATION
Respiratory Centers (Medullary Centers)
located in medulla oblongota, responsible for normal breathing
in pons, pneumotaxic - regulates apneustic centers, sets a balance between inspiration and exhalation. Stimulated by medullary inspiratory centers. Ends inspiration with negative feedback to stimulate expiration
Promotes continuous inspiration. controlled by pneumotaxic center and stretch reflex in lung (Hering-Breuer) when uncontrolled, creates looong inspiratory time
stretch reflex - located in smooth muscles in conducting airways - stimulated by inflation of the lung, then inhibits further inhalation because feels stretch
J Receptors - located in tissues between alveoli and pulmonary capillaries - stimulated by pulmonary edema, microembolism, rapid, shallow respiratory rate (restrictive)
in trachea, bronchi, and bronchioles - produce deep breath, bronchospasm, and cough
CO2 Effects on Ventilation
Stimulates central chemoreceptors, which send impulses to inspiratory center, which promotes stimulation of diaphragm, which sends impulse to phrenic nerve to take a deep breath.