Physiology Book Notes Flashcards
in the airways, sympathetic adrenergic neurons activate ________ on bronchial smooth muscle, leading to their _______ and _______
activated by ______
B2 receptors
Relaxation and dilation
epinephrine
in the airways, parasympathetic cholinergic neurons activate _______ receptors, leading to _______ and _______ of airways
muscarinic receptors
contraction and constriction
pouchlike evaginations of the walls of the respiratory bronchioles, the alveolar ducts, and the alveolar sacs
alveoli
Type __ pneumocytes synthesize pulmonary surfactant
type II pneumocytes
changes in pulmonary arteriolar resistance are controlled mainly by
O2, a local factor
inspiratory reserve volume
additional volume that can be inspired above tidal volume (~3000mL)
expiratory reserve volume
additional volume that can be expired below tidal volume (~1200mL)
residual volume
volume of gas remaining in the lungs after a maximal forced expiration (~1200mL)
inspiratory capacity
composed of the tidal volume plus the inspiratory reserve volume
physiologic dead space
total volume of the lungs that does not participate i ngas exchange
includes anatomic dead space
minute ventilation
total rate of air movement into and out of the lungs
alveolar ventilation
total rate of air movement into and out of the lungs but correcting for the physiologic dead space
the higher the alveolar ventilation, the more ___ is pulled out of the blood and the lower the ____ and ____
CO2
PACO2 and PaCO2
if CO2 production doubles, like during strenuous exercise, the ventilation must
also double, sto maintain a constant PACO2
when alveolar ventilation is halved, the decrease in PAO2 will be slightly _____ than the increase in PACO2 due to the ______
slightly greater
respiratory exchange ratio of 0.8
FEV1 refers to
the volume of air that can be forcibly expired in the first second
obstructive lung diseases, like asthma, COPD affect the FEV1/FVC ratio by
lowering both FEV1 and FVC
FEV1 is decreased more - increased RESISTANCE to expiratory air flow
restrictive lung diseases, like fibrosis, affect the FEV1/FVC ratio by
lowers but FEV1 and FVC
FVC decreased more
FEV1/FVC ratio will be increased
hysteresis accounts for the difference in lung volume during inspiration and expiration: lung volume is ______ during expiration than during inspiration
lung volume is greater during expiratino than during inspiration because compliance is higher during expiration than during inspiration
when the volume of the lungs is at FRC, the collapsing pressure of the ____ and the expanding pressure of the ____ equally oppose each other
collapsing pressure of lungs
expandnig pressure of chest wall
at volumes less than FRC, the collapsing pressure becomes ____ ____ the expanding pressure
the collapsing pressure becomes less than the expanding pressure
tendency to expand increases
airway pressure is negative
at volumes greater than the FRC, the collapsing pressure becomes _____ ____ the expanding pressure
the collapsing pressure becomes greater than the expanding pressure
lung and chest-wall system wants to collapse
airway pressure is positive
emphysema is associated with what change in compliance and why
loss of elastic fibers in the lungs, increasing the compliance
decreases collapsing force of lungs, increasing FRC
due to their higher FRC, patients with emphysema tend to
breathe at higher lung volumes and have barrel-shaped chests
fibrosis is associated with what change in compliance and why
decreases compliance - due to being a restrictive disease
(stiffening of lung tissues)
tendency of lungs to collapse is greater than tendency of chest wall to expand
new lower FRC is established
large alveoli have ____ collapsing pressure
small alveoli have ____ collapsing pressure
large have small collapsing while small have high collapsing pressure
surfactant has what effect on lung compliance
increases lung compliance, reducing work of expanding the lungs during inspiration
surfactant synthesis begins at week
24
infants born before 24 weeks will never have
surfactant
sites of highest airway resistance in the airways
medium-sized bronchi
