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

PollutantsA chemical agent in the environmentthat 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

HeredityPassing 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 carrierparent while other cases require bothparents to be carriers

Nonspecific Lines

of Defense

Skin (1st 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 (1st line of defense)

Digestive Tract

Respiratory Tract

Urogenital Tract

Cells that kill invaders (2nd line of defense)

Macrophages

Monocytes

Neutrophils

Natural Killer Cells

Immunological function of proteins (2nd line of defense)

Complement system

Causes bacterial or fungal cells to lyseby flooding it with proteins designed to attack the invading cell

Interferons (alpha, beta, gamma)

The proteins function as a messengerthat protects normal cells from infectionwhen they are in the vicinity of infectedcells

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 macrophagesthat 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