Respiratory pathophysiology Flashcards
Chemicals that contribute to increased airway resistance include:
a. nitric oxide
b. inositol triphosphate
c. vasoactive intestinal peptide
d. phospholipase C
e. leukotrienes
f. cyclic adenosine monophosphate
b. inositol triphosphate
d. phospholipase C
e. leukotrienes
All other thing being equal, the ___________ has the most significant contribute to airflow resistance.
radius of the airway
What physiologic systems determine airway diameter?
PNS (vagus nerve)
mast cells & non-cholinergic PNS
non-cholinergic PNS (nitric oxide)
SNS (circulating catecholamines)
What physiologic systems lead to bronchoconstriction?
PNS (vagus nerve)
mast cells & non-cholinergic PNS
What physiologic system lead to bronchodilation?
Non-cholinergic PNS (nitric oxide)
SNS (circulating catecholamines)
__________ supplies parasympathetic innervation to airway smooth muscle.
Vagus nerve (CN 10)
Stimulation of the ______ receptor produces bronchoconstriction
M3
_____________ & ______________ also release chemicals that promote bronchoconstriction
Mast cells & non-cholinergic c-fibers
There are no __________________ in airway smooth muscle
sympathetic nerve endings
B2 receptors embedded in airway smooth muscle are activated by
catecholamines in the systemic circulation
Non-cholinergic PNS stimulation produces ____________ which also promotes_______________
nitric oxide; bronchodilation
Smooth muscle contraction leads to
decreased airway diameter–> increased airway resistance–> reduce airflow
Smooth muscle relaxation leads to
increased airway diameter–> decreased airway resistance–> improved airflow
Mediators that lead to bronchoconstriction include
histamine
prostaglandins
leukotrienes
platelet activating factor
bradykinin
substance P
neurokinin A
calcitonin gene related peptide
Pulmonary medications can be broken down into
direct acting bronchodilators
anti-inflammatories
methylxanthines
Direct acting bronchodilators include
Beta 2 agonists
anticholinergics
Examples of direct acting bronchodilating anticholinergics include
atropine
glycopyrrolate
ipratropium
Examples of direct acting bronchodilating beta 2 agonists include
albuterol
metaproterenol
salmeterol
Anti-inflammatory drugs include
Cromolyn
leukotriene modifiers
inhaled corticosteroids
Examples of inhaled corticosteroids include
beclomethasone
fluticasone
triamcinolone
budesonide
flunisolide
Examples of leukotriene modifiers include
zileuton
montelukast
pranlukast
zafirlukast
Methylxanthines include
theophylline
Anesthetic agents with bronchodilating properties include
volatile anesthetics
ketamine
How do steroids work in the airway?
stimulates intracellular steroid receptors
regulates inflammatory protein synthesis leading to decreased airway inflammation and hyperresponsiveness
How do leukotriene modifiers work?
inhibits 5-lipoxygenase enzyme reducing leukotriene synthesis
How do anticholinergics work in the airway?
prevent Ach from binding to M3 receptors leading to decreased IP3 and decreased iCa2+
How does cromolyn work in the airway?
stabilizes mast cell membranes
How do beta 2 agonists work in the airway?
block cytokines, leukotrienes and histamine from leaving the mast cell and stimulate B2 receptors in the smooth muscle leading to increased cAMP & decreased Ca2+
Side effects of beta 2 agonists include
tachycardia, dysrhythmias, hypokalemia, hyperglycemia, tremors
Side effects of anticholinergics include
inhibits secretions–> dry mouth
urinary retention
blurred vision
cough
increased intraocular pressure with narrow angle glaucoma
Side effects of corticosteroides include
dysphonia
myopathy of laryngeal muscles
oropharyngeal candidiasis
possible adrenal suppression
Side effects of cromolyn include
negligible
Side effects of leukotriene modifiers include
negligible
How does theophylline work?
inhibits phosphodiesterase–> increased cAMP, increased endogenous catecholamine release
inhibits adenosine receptors
Side effects of theophylline are dependent on
plasma concentrations
At a plasma concentration of >20 mcg/mL of theophylline, side effects include
N/V, diarrhea, HA, disrupted sleep
At a plasma concentration of >30 mcg/mL of theophylline, side effects include
seizures
tachydysrhythmias
CHF
Which pulmonary function test is the MOST sensitive indicator of small airway disease?
a. forced expiratory volume in 1 second
b. forced expiratory flow 25-75%
c. forced vital capacity
d. diffusion capacity of carbon monoxide
b. forced expiratory flow 25-75%
_____________ measure how much air the lungs can hold at a single point in time
Static lung volumes
Examples of static lung volumes include
RV, ERV, Vt, IRV, FRC, IC, VC, TLC
__________ measure how quickly air can be moved in and out of the lungs over time
FEV1, FVC, FEV1/FVC ratio, and MMEF
____________ measures how well the lungs can transfer gas across the alveolocapillary membrane
Diffusing capacity
Examples of diffusing capacity include
diffusing capacity of carbon monoxide (DLCO)
A normal FEV1 value is
> 80% of the predicted value
A normal FEV1/FVC ratio value is
> 75-80% of the predicted value
Lung volumes and capacities are measured with
spirometry
The most sensitive indicator of small airway disease is
forced expiratory flow at 25-75% vital capacity (mild maximal expiratory flow rate)
A normal diffusing capacity (DLCO) is
17-25 mL/min/mmHg
