ERV, additional expiration volume expelled after the tidal volume
IRV + VT + ERV , the maximum air that you can inhale and exhale in one cycle.
Forced Expiratory Volumes
a healthy person can forcefully expel 80% of the air in their lungs in 1 sec. And
within 2 sec, they can expel over 90%.
In 3 sec. 98% or more is expelled.
What is the primary driver of respirations?
What is functioning for rate of breathing?
Medulla – Dorsal Respiratory Group – always functioning for rate of breathing
What changes depth/rate of breathing?
Pons – Pneumotaxic Center – changes depth and modifies rate of breathing.
1. Carotid bodies – glossopharyngeal nerve, CO2, O2 and pH
2. Aortic bodies – vagus nerve, CO2, O2 and pHpCO2 – small increases quickly trigger deeper and faster breathing. hypercapniapO2 – requires large decreases, to 40 mm Hg, to cause increases in breathing. hypoxia
3. Stretch receptors – monitor the expansion of the lungs, protective reflexes.
inflation reflex, prevents overstretch of the lungs
allergen hypersensitivity reaction, IgE and Mast Cells = histamine release in bronchioles
chronic condition, variety of causes including smoking, coal mining etc
Decreases surface area and elastic fibers, increases diffusion barrier for gases
patients have both obstruction of the airways anddecreased diffusible alveolar surface area.
Expiratory wheeze due to bronchiolar constriction AND alveolar crackles due to lung tissue inflammation.
Long/Short acting Brochiodilators
Albuterol – short acting, ‘rescue inhaler to stop bronchiole spasms. Beta-agonist (Symp. NS)
Salmeterol- long acting, used for maintenance to bronchiole spasms Beta-agonist.
reduces mucus & dilates bronchioles.
long acting tablet, broncho-dilator esp. night asthma.