Respiration's First Defenses Flashcards
When you have a cold and get “congested,” what does that actually mean?
The turbinates swell.
this tends to happen one side at a time - a mysterious process called the nasal cycle
Why do you need to be careful placing an NG tube in someone who’s had sinus surgery?
The remaining bone is thin… and you could put the tube through the back of a sinus and into the brain.
It’s important to warm and humidify air breathed in.
Yes.
Why is turbulence created by the turbinates good?
It encourages particulate matter to drop out in the mucus.
It makes it easier to smell, too.
Sniffing directs more air flow toward the olfactory bulbs.
That makes sense.
95% of pollen-sized particles are deposited in the anterior nasal cavity.
(but only 60% of 2 micron particles are trapped)
Useful.
smaller stuff gets deeper into lungs
Do we know what the paranasal sinuses are actually for?
Not really.
They might lighten the skull, add resonance to the voice, and/or provide a crumple zone…
2 layers of mucus?
Is the thickness variable?
Gel (mucus) and sol (aqueous).
The thickness of the mucus layer is variable, but the sol layer must be kept constant for cilia beating to work.
Does the cilia beat frequency vary?
It sure does. At the faster mucus is moving, the easier it is for it to move.
What’s interesting about the direction in which cilia beat?
Why is this important?
They know what direction to beat… in the sinuses, eg. this is toward the opening in a defined pattern.
Making a hole at the bottom of a sinus won’t help it drain. Rather, the existing hole should be enlarged.
Secretory IgA is important.
It protects against viruses and bacteria.
If deficient -> recurrent sinusitis.
What kind of defensins are secreted in the airway epithelia?
What do they do?
Beta defensins.
Direct antimicrobial activity by forming pores in bacteria.
How is lactoferrin microbicidal?
Inhibits microbial growth by sequestering iron.
Lysozyme is particularly good against what kind of bugs?
Gram-positive bacteria - as it breaks down peptidoglycan.
Do surfactants have antimicrobial activity?
Yes, the hydrophilic ones, SP-A and SP-D help pathogens get cleared.
