Tears

Definition

Tears are a liquid secretion produced by the lacrimal glands to lubricate the eyes and provide immune defense. They contain enzymes and antimicrobial proteins that protect against pathogens.

5 Must Know Facts For Your Next Test

1. Tears contain lysozyme, an enzyme that breaks down bacterial cell walls.
2. The tear film consists of three layers: lipid, aqueous, and mucous.
3. Tears help remove debris and microorganisms from the surface of the eye.
4. Antimicrobial peptides in tears, such as defensins, contribute to innate immunity.
5. The production of tears is part of both the body's innate and adaptive immune responses.

Review Questions

• What enzyme found in tears is responsible for breaking down bacterial cell walls?
• Name the three layers that make up the tear film.
• How do tears contribute to the body's immune defenses?

Related terms

Lysozyme: An enzyme found in tears that breaks down bacterial cell walls.

Lacrimal Gland: A gland located above each eye that produces tears.

Defensins: Antimicrobial peptides present in tears that help protect against pathogens.