Barrier Function

Definition

Barrier function refers to the ability of the skin and eyes to act as a protective barrier against external threats, such as pathogens, chemicals, and physical damage. This function is crucial in maintaining the body's homeostasis and preventing the entry of harmful agents into the body.

5 Must Know Facts For Your Next Test

1. The skin's barrier function is primarily provided by the stratum corneum, which acts as a physical and chemical barrier to prevent the entry of harmful substances and the loss of water from the body.
2. The tear film in the eyes contains antimicrobial enzymes and proteins that help protect the eyes from infection and environmental threats.
3. Mucous membranes in the eyes, nose, and mouth trap and expel foreign particles, pathogens, and other harmful agents, preventing their entry into the body.
4. The normal microbiota of the skin and eyes play a crucial role in maintaining the barrier function by competing with pathogenic microorganisms and producing antimicrobial compounds.
5. Disruption of the barrier function, such as through skin damage or eye irritation, can lead to increased susceptibility to infection and other health problems.

Review Questions

• Explain the role of the stratum corneum in the skin's barrier function.
  • The stratum corneum is the outermost layer of the skin and serves as the primary physical and chemical barrier. It is composed of dead, flattened skin cells (corneocytes) and lipids that work together to prevent the entry of harmful substances, such as pathogens and chemicals, while also preventing the loss of water from the body. The unique structure and composition of the stratum corneum, including the presence of natural moisturizing factors and antimicrobial peptides, are essential for maintaining the skin's barrier function and overall health.
• Describe how the tear film and mucous membranes contribute to the barrier function of the eyes and other body cavities.
  • The tear film that covers the surface of the eye contains a variety of antimicrobial enzymes and proteins, such as lysozyme and lactoferrin, which help protect the eye from infection and environmental threats. Additionally, the mucous membranes lining the eyes, nose, and mouth trap and expel foreign particles, pathogens, and other harmful agents, preventing their entry into the body. The constant production and movement of mucus, along with the presence of immune cells and antimicrobial compounds, are crucial for maintaining the barrier function of these body cavities.
• Analyze the role of the normal microbiota in supporting the barrier function of the skin and eyes.
  • The normal microbiota, or the community of beneficial microorganisms, that reside on the skin and in the eyes play a vital role in maintaining the barrier function. These microorganisms compete with pathogenic microbes for resources and attachment sites, preventing their colonization and invasion. Additionally, the normal microbiota produce antimicrobial compounds, such as bacteriocins and organic acids, that inhibit the growth of harmful microbes. By supporting the skin and eye's natural defenses, the normal microbiota contribute to the overall barrier function and help protect the body from external threats. Disruption of the normal microbiota, through factors like antibiotic use or skin/eye irritation, can compromise the barrier function and increase the risk of infection and other health problems.

Related terms

Stratum Corneum:

The outermost layer of the skin that serves as the primary physical and chemical barrier, composed of dead, flattened skin cells and lipids.

Tear Film: The thin layer of fluid that covers the surface of the eye, providing lubrication, immune protection, and antimicrobial properties.

Mucous Membranes:

The moist, protective linings of various body cavities, including the eyes, nose, and mouth, which trap and expel foreign particles and pathogens.