Pulmonary Pathology and Diseases

Question 0

what comprises the peripheral airways?

Answer 0

Alveoli

where gas exchange occurs

Question 1

what comprises the central airways?

Answer 1

trachea, bronchi, bronchioles

Question 2

What determines where inhaled medication deposits?

Answer 2

particle size

10 microns goes to the central airways (bronchial constriction treatment)

Question 3

what happens when you inhale a drug and it is deposited in the peripheral airways?

Answer 3

systemic absorption:
short transit distance between the gas in the alveoli and the pulmonary capillaries - no barrier for absorption into blood stream
particle size of 1 micron or smaller can get to alveoli.

Question 4

How does the pulmonary system condition inhaled air?

Answer 4

air inside the alveoli is very humid (almost 100%)
inhaled gas is prepared for the internal environment through the nose or mouth - warms and humidifies it
large airway surface area plus rich blood supply –> very effective at increasing air temperature and humidity

Question 5

what are the mechanisms of defense?

Answer 5

filtration: nose hairs get rid of large particulates, mucus helps as well
Mucociliary escalator: trachea down to bronchioles - particles trapped in mucus are removed from airways by coordinated ciliary beating towards pharynx (where you swallow it or spit it out)
Nerves/reflexes: modulate airway smooth muscle tone, mucus secretion, ciliary beat frequency, mucosal thickness.
When you inhale dust or an irritant, airways will close down so that those particles don’t get into your lungs –> protective mechanism
influence ventilation rate and depth: nerves/reflexes promote more rapid, shallow breathing when you inhale a particle so you don’t inhale particle as deeply

Question 6

What are the pulmonary nerves comprised of?

Answer 6

Afferent nerves (sensory): C-fibers, irritant receptors --> can be stimulated by things like citric acid
Efferent nerves (motor nerves): Cholinergic --> PNS nerves, Nitrergic --> dialator, Tachykinergic --> substance P

Question 7

Are there any sympathetic nerves in airway smooth muscle?

Answer 7

Nope.
adrenergic beta 2 receptor activators like albuterol work because epinephrine comes from the adrenal medulla into the blood stream

Question 8

How do we measure pulmonary function?

Answer 8

Spirometry:
measures lung volumes and capacities (the volume of air that a patient is breathing in and out)
Total Lung Capacity: volume of air in lungs at full inspiration. Fundamental to flow rates (residual volume + vital capacity)
Force vital capacity: breathe in as fully as possible & then breathe out as quickly and as fully as you can
Residual Volume: volume of air remaining in lungs after maximal expiration