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Ch. 5 - Fighting Disease
Transcript of Ch. 5 - Fighting Disease
5.1 - Infectious Disease
Who is Joseph Lister?
5.2 - The Body's Defenses
How are your body's defenses keeping you health like a battle scene or a war?
5.3 - Preventing Infectious Disease
5.4 - Noninfectious Disease
Why are people living longer than they used to?
5.5 - Cancer and the Environment
How does this war help maintain homeostasis?
Barriers That Keep Pathogens Out
Your body has three lines of defense:
Mouth & Stomach
The Inflammatory Response
The inflammatory response is the 2nd line of defense your body has. It is when fluid, and white blood cells leak from the vessels into nearby tissues to fight pathogens.
White Blood Cells
- there are different types, that do different things, but they all fight disease. Phagocytes are the ones involved in the inflammatory response.
- blood vessels in the infected area widen to allow for more blood flow, this results in the area being red, swollen, and warmer than usual.
- some pathogens don't grow as well or even at all at higher temperatures
The Immune System
Your body's 3rd line of defense is the
Lymphocytes can distinguish between different pathogens.
- identify pathogens, each kind of T cell recognizes a different pathogen using markers called
- produce proteins that destroy pathogens, these proteins are called antibodies, each kind of B cell produces one kind of
AIDS - Acquired Immunodeficiency Syndrome
HIV - Human Immunodeficiency Virus
HIV is the only virus we know of that actually attacks the immune system, it attacks and destroys T cells.
More than 40,000,000 people worldwide have HIV, over 3,000,000 of them are kids under the age of 15!
HIV is spread through bodily fluids.
How would you design an experiment to find out which type of cleaner is more effective at killing bacteria?
- the body's ability to destroy pathogens before they can cause disease
- production of antibodies in response to the presence of a pathogen
After T cell and B cell fight of a pathogen they remember that pathogens antigen, so they can quickly fight it off next time.
- the process by which harmless antigens are deliberately introduced into a person's body to produce active immunity
- usually consists of pathogens that have been weakened or killed but can still trigger an immune response
- a chemical that kills bacteria or slows their growth without harming body cells
- when antibodies are given to a person to help fight the pathogen
Passive immunity may only last for a few months, whereas active immunity lasts a long time.
A baby can acquire passive immunity from their mother before they are born.
Louis Pasteur - proposed that infectious disease in humans are caused by microorganisms
Alexander Fleming - observed that bacteria growing on lab plates where killed when fungi grew on the same plate, from this he discovered penicillin
- diseases that are not caused by pathogens in the body
- disorder in which the immune
system is overly sensitive to a foreign substance
- any substance that causes an allergy
- a chemical that is responsible for the symptoms of an allergy
- a disorder in which the respiratory passages narrow significantly
- chemical that enables body cells to take in glucose from the blood and use it for energy
- condition in which the pancreas either fails to produce enough insulin or the body's cells fail to properly use insulin
Type I - begins in childhood, must get injections
Type II - usually develops during adulthood, may be able to control symptoms through diet, weight control, and exercise
- is a disease in which cells multiple uncontrollably, destroying healthy tissue
- abnormal tissue masses formed from cells that have divided over and over
Cancer cells can be carried by blood or lymph vessels to the rest of the body.
Causes of Cancer:
- substances or factors in the environment that can cause cancer
Surgery, drugs (chemotherapy), and radiation are all used to treat cancer.
Percivall Pott hypothesized that the soot ground into the skin of chimney sweeps contained carcinogens.
Linking Cancer to the Environment
The carcinogens found in soot are the same substances found in tar from smoking cigarettes.
To reduce the risk of cancer carcinogens need to be removed from the environment or people need to be protected from them.
Environmental Carcinogens Today
Three important carcinogens found in our environment today are: ultraviolet light, vinyl chloride, and arsenic.
- some UV rays are absorbed by the ozone layer but not all, overexposure to UV light can cause skin cancer
- mostly used to make PVC (which is used in everything from pipes and packaging to car parts, causes cancer of the liver, brain , or lungs
- naturally occurs in soil and rock, was once used in pesticides but now used to treat wood, can cause cancer of the liver, bladder, kidneys, and lungs
Understanding Infectious Disease
- organisms that cause disease
- disease caused by the presence of a living thing within the body, usually pathogens that cause harm
Louis Pasteur and Robert Koch both greatly helped our understanding of infectious diseases.
Kinds of Pathogens
Four main groups of pathogens:
- single celled microorganisms that can cause harm directly or by producing toxins (poisons) ie. clostridium botulinum
- much smaller than bacteria, can only reproduce inside living cells
- mold and yeasts, grow in warm, dark, moist places and can cause diseases such as athletes foot and ringworm
- diseases such as malaria and African sleeping sickness are caused by protists
How Pathogens are Spread
Pathogens can spread through:
infected people - physical contact, indirect contact
soil, food, or water - ingesting contaminated food or water...
contaminated objects - touching any object that has been handled by an infected person, tetanus can be contracted if you step on a contaminated object
infected animals - a bite from an infected animal (dogs, cats, mosquitoes) can pass the pathogen on to you
He developed new surgical techniques and the idea of antiseptic.