BVS 511- APPLIED BIOMEDICAL SCIENCE

Immune System

Immunity: The ability to resist organisms or toxins that tend to damage tissues and organs

• Distinguishes “nonself” organisms and molecules from “self”

• Neutralizes threats to human body

Three Layers of Defense

1. Barriers

2. Innate Immune System

3. Adaptive immune system

Keratinocytes

• Produce cells of the outermost later of the epidermis (stratum corneum)

• Continuously dividing keratinocytes and sloughing of stratum corneum removes microbes attached to cutaneous surfaces

Stratum Corneum

Composed of dead, tightly layers and cornified squamous cells

• Creates watertight barrier that prevents dehydration

• Makes microbe-inhospitable dry environment on the surface skin

Constant sloughing the stratum corneum layer which removes microbes attached to cutaneous surfaces

Mucous Membrane

• Epithelium of mucous membranes lines ALL the body cavities that come into contact with environment

• (Ex respiratory, GI, Urogenital tracts)

Respiratory Tract

Mucus traps inhaled bacteria, fungi and other particles

GI tract

mucus and mucous membranes help protect epithelial cells