Lung Defenses and Airway Surface Liquid

Main airway epithelial function

Create barrier and move mucus

Goblet cell function

Produce mucus

Major mucus component

Mucins

Mucin characteristic

Highly glycosylated

Mucin charge

Negatively charged

Mucin function

Trap pathogens

Submucosal glands contain

Mucoid cells and serous cells

Serous cell function

Secrete isotonic fluid

Human airway aqueous layers

Mucus layer and airway surface liquid

Mucus layer function

Trap inhaled bacteria and particles

ASL function

Support ciliary beating

Periciliary layer abbreviation

PCL

Airway defense mechanism

Mucociliary clearance

Defensins

Small antimicrobial peptides

Defensin size

12-50 amino acids

Defensin charge

Positively charged

Defensin property

Hydrophobic residues present

Defensin activity

Kills microbes

Defensin resistance

Microbes rarely develop resistance

Defensin activity sensitivity

Salt-sensitive

High salt effect on defensins

Inactivates defensins

ASL contents

Proteases, antiproteases, antibiotics, antibodies, oxidants, antioxidants