Transcript How Contaminants Enter the Human Body

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Three different ways:
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Inhalation (breathing)
Ingestion (eating)
Absorption through skin
Breath in through nose and mouth
Pharynx
Trachea
Bronchial
Tubes
Lungs
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Diaphragm contracts
air sucked in
Diaphragm relaxes
lungs expand
air forced up and out
Bronchial tubes (bronchus)
Alveoli
capillaries
• Alveoli = site of gas exchange
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Oxygen (O2)
Carbon Dioxide (CO2)
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Carried to cells in body
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bronchioles
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Smoke, bacteria, dust
Nasal passage ways & bronchial tubes = mucus
and cilia
Mucus = traps inhaled particles
 Cilia = move particles in wave like motions to be
expelled through sneezing and coughing
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- Can only defend against
low doses ~ no defence
against VOC’s and pesticides
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Ingestion = process of eating and drinking
Digestion = break down of food into smaller
pieces in order to absorb chemical nutrients
Carbohydrates
 Proteins
 Fats
 Vitamins and Minerals
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Starts in mouth with chewing
 Teeth = break up food into smaller pieces
 Saliva = moistens and breakdown food
Swallow food
esophagus
stomach
small intestine (most nutrients absorbed)
Mixed with digestive substances from liver and pancreas
Liver = bile (breakdown and absorb fat)
 Pancreas = very important organ in digestion - breakdown
carbohydrates, proteins, fats
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Intestinal walls lined with villi
other side = capillaries
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Nutrients absorbed through small intestine walls
into circulatory system and distributed to rest of
cells in body
Food not absorbed in small intestine
passed to large intestine = water absorbed,
compacted into feces
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Vomiting
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Contents from middle of intestine up forced out
through mouth
Liver
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Filters blood ~ removes poisons that get across villi
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Skin = largest organ; first line of defence
against outside world
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Makes Vitamin D with sunlight ~ calcium
Structure:
 Epidermis
Dermis
Subcutaneous
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Epidermis:
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Dermis:
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Two layers (top = dead cells, bottom = new cells)
Contains nerve endings and capillaries, sweat glands
Subcutaneous
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Fat cells
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Keeps out water and contaminants
Can absorb chemicals in cleaning products and
in workplace, as well as oils, tars, alcohols,
pesticides
Harm layers of skin
Get into capillaries and carried to cells of body
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Heart, veins, arteries,
capillaries
Carries blood to cells of body
and transports nutrients and
wastes
Nutrients = carbohydrates,
proteins, fats, vitamins,
minerals
Wastes = carbon dioxide,
water, heat
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Fights pathogens when skin is
wounded (white blood cells)
Contaminants can get into
blood through wounds from
sharp objects, insect and
animal bites
Carries contaminants to
organs, tissues, systems