INNATE IMMUNITY

KEY TERMS

• Immunology: study of the body’s reactions to foreign substances (antigens)

• Serology: study of the immune (non-cellular) components in serum, particularly antibodies ; This tests the serum

• Immunity: the body’s ability to resist/fight off infection; act of staying healthy

• Antigen: any substance that’s capable of drawing out an immune response & the formation of antibodies

• Innate (Natural) Immunity: an individual’s ability to resist infection using the basic body defenses they are born with

• Adaptive (Acquired) Immunity: an individual’s ability to resist infection using pathogen-specific defenses after a previous exposure

• External Defenses: function as a barrier to keep foreign substances (microbes and pathogens) from entering the body

• Internal Defenses:

INNATE VS. ADAPTIVE IMMUNITY

Innate Immunity

• rapid response

• Non-specific reaction — goes for all types of antigens encountered

• Has no memory — no prior exposure

• Involves both external and internal defenses

Adaptive Immunity

• Acts slower, but lasts longer

• A more specific, tailored response

• Has memory

• BOTH INNATE & ADAPTIVE IMMUNE RESPONSES ARE ESSENTIAL FOR US TO BE ABLE TO EFFECTIVELY RESIST INFECTION.

• THEY’RE INTERDEPENDENT PROCESS, IF SOMETHING GOES WRONG IN EITHER BRANCH, OUR IMMUNE SYSTEMS WILL BE WEAKED AND MORE SUSCEPTIBLE TO INFECTION.

BODY DEFENSES

External Defenses — 1st line of defense of innate immune response

• Structural barriers — ex. Skin, mucous membranes

  • Skin is very effective of keeping pathogens from entering our body

• Secretions — ex. Lactic acid in sweat, fatty acids in sebaceous glands

  • Keeps skin at acidic pH (approx. 5.6) so no microorganisms grow

• Mechanisms unique to each organ system:

  • Respiratory tract — mucous, cilia, coughing, sneezing

  • Genitourinary tract — urine, vaginal secretions

  • Gastrointestinal tract — hydrochloride acid in stomach (pH approx. 1.0)

  • Tears & saliva — enzymes

  • Normal bacterial flora