Transcript disease - Alevelsolutions

DISEASE
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Pathogens
1. Pathogens is any organism that causes disease.
2. Pathogens include microorganisms and some larger organisms such
as tapeworms.
3. Pathogenic microorganisms include some bacteria, some fungi and
all viruses.
4. Pathogens need to enter the body to cause harm. How do they get
in?
Entry of pathogens – Gas exchange
1. Pathogens can enter the body by the Gas exchange system: by
breathing in air that contains pathogens you could be affected.
Most pathogens will be trapped in your mucus lining the lung
epithelium. These cells also have cilia (hair like structures) that beat
and move the mucus up the trachea to the mouth where its
removed. Some pathogens reach the alveoli where they invade and
cause damage.
Skin
• Damaged skin can allow pathogens to enter your bloodstream as well.
• The blood clots at the area of damage to prevent pathogens from
entering. Since this takes time pathogens may enter before the clot os
formed.
Digestive system
• Food can contain pathogens that will enter the stomach; most of
which will be killed by the acidic conditions of the stomach. Some
pathogens may survive, pass into the intestines where they can
invade cells of the gut wall and cause disease.
How do pathogens cause disease?
1. Production of toxins – many bacteria release toxins. Eg. the bacteria
that causes tetanus produces a toxin that blocks the function of
certain nerve cells, causing muscle spasms.
2. Cell damage – Pathogens can physically damage host cells by
• Rupturing them to release nutrients (proteins etc.) inside them
• Replicating inside the cells and bursting them when they are
released. Some viruses do this as well.
• Breaking down nutrients inside the cell for their own use. This starves
and kills the cell.
Lifestyle can affect your chances of disease!
• Coronary heart disease (CHD) is a disease that affects your….(you
guessed it) heart.
• This can come from a diet high in saturated fat or salt.
• Smoking, lack of exercise and excessive alcohol intake can lead to high
blood pressure, which can damage the heart and the blood vessels,
increasing the risk of CHD.
Cancer
• Cancer is the result of uncontrolled cell division. You increase your
chances of getting cancer by:
• Smoking – mouth, throat and lung cancer
• Excessive exposure to light – skin cancer
• Excessive alcohol intake – liver cancer
Exam question
answer
• Golgi apparatus
• Function is to process proteins
OR
• Mitochondria - function to release energy
Exam question 2
• What is the name of the process that allows oxygen to pass from an
alveolus in the lungs into the blood?
• Describe 2 ways in which the alveoli is adapted for efficient gas
exchange.
answers
• Diffusion
• Thin walls/cells
• Total surface area is large