How and Why do we get sick? The Non-specific Lines of defense

How and Why do we get sick? The Non-specific Lines of defense

Disease A possible disruption in homeostasis A lack of stability within the body May be caused by heredity, microorganism, macroorganism, pollutants, organ malfunction, or harmful life choices

Causes of Disease Microorganisms (protists and bacteria) Macroorganisms (parasites and fungi) Viruses Organ Malfunction Harmful Lifestyle Pollutants Heredity ***Any microorganism (including viruses) or macroorganism that causes disease is a pathogen

Micro and Macro Organisms Microorganisms are living things that cannot be viewed with the naked eye **Bacteria and Protists (euglena, ameba, and paramecium) are examples Macroorganisms are living things that can be viewed with the naked eye ** Fungi and parasites (various worms) are examples The disorders may be airborne or infectious/ communicable (passes on from person to person)

Viruses Are nonliving microorganism type particles that cause disease (pathogen) May be RNA or DNA in type Are usually airborne and/or infectious

Harmful lifestyle The abuse of drugs (legal or illegal) Stress Lack of exercise Poor eating, hygiene, and sexual experiences *** These all have the potential to cause disruptions in your body s stability or homeostasis

Pollutants A chemical agent in the environment that may upset the stability or overall homeostasis of your body May be found in the air, food, water, or land May cause a variety of diseases

Heredity Passing on defective genes from one generation to the next will classify a disease as inherited or hereditary Many times the parent will not have the actual disease but will have the defective gene (a carrier) In some cases all you need is one carrier parent while other cases require both parents to be carriers

Nonspecific Lines of Defense

Skin (1 st line of defense) Defends the body against invasion Prevents excessive loss of water Is nearly impenetrable

Reinforcements for skin protection Sweat glands Oil glands Multiple layers Epidermis Dermis Subcutaneous Tissue

Lines of Defense not protected by the skin (1 st line of defense) Digestive Tract Respiratory Tract Urogenital Tract

Cells that kill invaders (2 nd line of defense) Macrophages Monocytes Neutrophils Natural Killer Cells

Immunological function of proteins (2 nd line of defense) Complement system Causes bacterial or fungal cells to lyse by flooding it with proteins designed to attack the invading cell Interferons (alpha, beta, gamma) The proteins function as a messenger that protects normal cells from infection when they are in the vicinity of infected cells

Inflammatory Response Is a localized nonspecific response to an infection The infected or injured cells release a chemical signal that acts as an alarm of sorts The affected area becomes red, warm, and swollen

Temperature Response Interleukin-1 is released by macrophages that encounter invading microbes Is carried to the brain by the blood Directs the neurons of the hypothalamus to raise the body s temperature several degrees above normal to produce a fever Fever stimulates phagocytosis and causes the spleen and liver to store iron

Summary Causes of disease First lines of defense Second lines of defense Inflammatory response Temperature response