1. Skin and Mucus: Pathogens-Away! By: Piggy G, Tiny, Reeses, and Pikachu

2. Pathogen:  living organism that causes a disease includes: viruses, bacteria, protozoa, fungi, and worms (exposure doesn’t always result in disease)  Definition: An agent of disease. A disease producer. The term pathogen most commonly is used to refer to infectious organisms. Less commonly refers to a noninfectious agent of disease such as a chemical. compounded from patho- meaning disease + -gen indicating a producer.patho-......Hence, a disease producer. Transmitted though: inhalation, physical contact, burrowing through skin, body fluids, ingestion...etc.

3. Various Pathogens

4. Active vs. Passive Immunity  active immunity Naturally acquired occurs when the person is exposed to a live pathogen, develops the disease, becomes immune as a result of the primary immune response Artificially acquired active immunity can be induced by a vaccine, a substance that contains the antigen (vaccine stimulates a primary response against the antigen w/o causing symptoms of the disease)  Passive immunity Artificially acquired passive immunity is a short-term immunization by the injection of antibodies that are not produced by the recipient's cells Naturally acquired passive immunity occurs during pregnancy, in which certain antibodies are passed from the mother into the fetal bloodstream.

5. Skin  Skin: outer barrier to infection  first line of defense is nonspecific Epidermis: upper layer (dead cells)  Good barrier against most pathogens because cells aren’t alive  composed of multiple layers of tightly packed cells, which few pathogens can penetrate on their own  natural shedding of dead skin cells removes many attached microorganisms  epidermal dendritic cells that actively patrol the skin to phagocytize (engulf and digest) pathogens. Dermis: lower layer (live cells)  beneath epidermis, contains protein fibers called collagen  Collagen is a tough fibrous protein, gives skin the strength and pliability to resist abrasions that could introduce microorganisms

6. ...More Skin (2 layers, 2 slides – get it? Haha!)  Chemical Components of the Skin's Defense:  Perspiration Secreted by the skin’s sweat glands, contains salt and enzymes; few microbes can live in a highly saline environment, like skin’s surface; lysozymes in sweat are a type of enzyme that can destroy the cell walls of bacteria  Sebum Sebum secreted by skin’s sebaceous (oil) glands; oil helps keep skin pliable, less likely to break/tear; lowers pH of the skin to acidic level that inhibits the growth of many types of bacteria

7. Mucus mucous: mucous membrane is a part of bodily defense like skin, but lines the inner surface of the body; protects the body against the acids and ph changes inside our body; since it is a thick layer it also act as shock absorber mucus: lines passageways stickiness traps pathogens preventing them from reaching cells they could infect secretes lysozyme which kills pathogens

8. Mucous-secreting membranes line all body cavities open to the outside environment  Unlike the skin’s surface epidermal cells, the epithelial cells on the outermost layer of mucous membranes are alive  tightly packed together, preventing entry of pathogens into the body  Epithelial cells continually shedding; the discarded cells carrying away any attached  (think about the inside of your nose...) See? Mucus is good! -->