Pulmonary Path & Pharm Flashcards
Upper Airways
nose/pharynx
Central Airways
tracheo-bronchial
Peripheral Airways
alveoli (pulmonary)
Airway Pulmonary Function
-Gas exchange -Air conditioning -Defense
Gas exchange
-alveolar surface optimized for gas exchange -short transit distance -large surface area
Air conditioning
-inhaled gas prepared for internal environment -large airway surface area + rich blood supply–>very effective at increasing air temp/humidity 73deg/43% –> 90deg/98% humid
Defense
a. filtration: nose hairs filter out large particles b. mucociliary escalator: trachea down to bronchioles, particles trapped in mucus removed from airways by coordinated ciliary beating toward pharynx c. nerves/reflexes: modulate airway smooth muscle tone, mucus secretion, ciliary beat frequency (mucosal thickness), influcences rate and depth by afferent and efferent nerves
Spirometry
clinical measurement of pulmonary function -measures lung volumes and capacities
total lung capacity
volume of air in lungs at full inspiration
residual volume
volume of air remaining in lungs after maximal expiration
What would you predict to happen to residual volume in a pt experiencing severe bronchoconstriction?
bronchoconstriction in central airways will cause decreased airflow making it harder for air to get into peripheral airways, and exhalation will be harder too, causing an increase in residual volume b/c of gas trapping in lungs
Forced Expiratory Flow Measurements
-FEV-1: forced expiratory volume in 1 second -FVC: forced vital capacity
FEV-1
forced expiratory volume in one second -% predicted FEV-1 = FEV-1 normalized to age, gender, and body weight -estimate of severity of airway obstruction
FEV-1/FVC
useful measure of pulmonary function -estimate of airway obstruction that may not be fully reversible (especially when measured after a bronchodilator)
GOLD classification of COPD
-Mild: FEV-1/FVC 80% -Severe: FEV-1/FVC <30%
Peak Flow Measurements
-simplest measure of expiratory flow -may be used for self-eval and documentation of lung ventilatory function –>patient inhales completely to TLC and then exhales rapidly and completely into a peak flowmeter–> measures maximal (peak) flow rate of expiration
What would you expect to happen to peak expiratory flow rate of a pt experiencing bronchoconstriction?
Flow will decrease! Patients can have airflow obstruction and not realize it, so peak flow meter is good for monitoring peak flow and whether airways are opening up or not
Airway defenses
- Mucociliary clearance
- Ventilatory responses
Mucociliary clearance
- mucus + ciliated epithelium
- traps and removes inhaled material
Ventilatory Responses
- change in rate
- change in depth
- decreased lung penetration
- facilitates mucus removal (reflex parasympathetic nerve activation)
Airway Mucus
- secreted from mucosal and submucosal glands
- influenced by neural and inflammatory mediators
- gel-like material
~water (90-95%), proteins, phospholipids, mucins (elongated glycoproteins)
-nature of the mucus influences treatments (result of different mucins)
Mucins
multiple different mucins
- impart different physical properties to mucus
- proportions change in disease (normal, asthma, COPD, CF)
Interactions between Mucin molecules include:
- covalent
- ionic bonds
- hydrogen bonds
- van der Waals forces
- intermingling
- interaction w/ other molecules in mucus, e.g. DNA, F-actin
Airway mucus function
- serves hygienic function
- traps inhaled material deposited on central airway lumen
- cleared from airways by mucociliary escalatory and coughing
Mucus clearance from airways affected by its:
- viscoelasticity (thickness)
- tenacity/adhesiveness
Mucociliary Clearance
- mucus moved from airways towards pharynx by coordinated beating of cilia on epithelial cells
- mucus floats on a sol layer
Clearance affected by:
a. Mucus Viscosity: water content, mucus constituents, extent of cross-linking, pH/ion content
b. Mucus Volume: water content, gland function
c. Ciliary Beat Frequency: inflammatory mediators, nerves
What could an atropine-like drug do to mucociliary clearance?
Atropine blocks PNS so it would decrease mucociliary clearance, can lead to obstructive and bacterial proliferation and possibly infection
Cough
defensive reflex that clears larynx through main bronchi of:
-mucus, foreign particles, infectious organisms
Cough caused by:
-viral infections, asthma, heart failure, drugs, postnasal drip, bronchitis, pneumonia, allergy, lung cancer, foreign particles
Cough Reflex
cerebral cortex–>cough center-> cough receptor or ventilatory muscles
Cough Receptors and Stimuli
irritant: change in pH, change in tonicity irritant, cig smoke, mechanical stimulation, pulmonary congestion
C-fiber: bradykinin, capsaicin
stretch: mechanical stimulation
ventilatory muscles
intercostals, diaphragm, abs, laryngeal muscles
Uncontrolled, unproductive cough can cause:
-prevents sleeps, rib fractures, syncope, fatigue, pneumothorax, rupture of surgical wounds, muscle pain, urinary incontinence
Disease: change in cough sensitivity
increased coughing to normal stimulus
a. Peripheral Sensitization: increase cough RECEPTOR sensitivity
b. Central Sensitization: change in cough CENTER sensitivity
Mucus and Airway Disease
disease–> decreased mucus clearance by :
- increased volume of mucus secreted
- increased viscosity, harder to clear
- increased tenacity, stickier mucus
Decreased mucus clearance can result in mucus accumulating in the airways. What problems could this cause?
can cause airway obstruction, bacterial proliferation, and infection
Drugs used to treat airways disease target:
A.) Mucus Viscosity (mucolytic) B.) Mucus Hydration (expectorant) C.) Cough (antitussive) D.) Airway Smooth Muscle (Bronchodilator) E.) Inflammation (anti-inflammatory) F.) Neural Mechanisms (anticholinergic) G.) Upper Airway Congestion (vasoconstrictor) H.) Infection (antibiotic)
