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B1.1 Keeping Healthy
B1.1.1 Diet and Exercise
A combination of a balanced diet and regular exercise is needed to help keep the body
A healthy diet contains the right balance of the different foods you need and the right
amount of energy.
These foods should provide…
Exercise increases the proportion of muscle to fat.
Inherited factors can influence our health.
We can inherit genes from our parents which can influence our metabolic rate.
We can also inherit genes which influence our cholesterol level.
Cholesterol is a substance that our body creates from fat that we…
B 1.1.2 Infectious Disease
Our bodies provide an excellent environment for many microbes which can make us ill once
they are inside us. Our bodies need to stop most microbes getting in and deal with any
microbes which do get in. Vaccination can be used to prevent infection.
The immune system
The body has different ways of protecting itself against pathogens.
White blood cells defend our internal environment from pathogens
These form part of our immune system.
There are various types of white blood cells:
Cells that ingest and destroy microorganisms
Cells that produce antitoxins that destroy toxins…
This idea was not readily accepted people were not aware of microorganisms.
Nowadays, it is standard practice for people to wash hands after treating patients, to
prevent disease being transmitted to other patients.
Using drugs to treat disease
Some medicines, including painkillers, help to relieve the symptoms of infectious…
What can be done?
Doctor's should only prescribe antibiotics when necessary and not for viruses.
It is important that if you are prescribed antibiotics you take the whole course.
o A lot of people will stop taking the antibiotic when they feel better.
o If you do this, you…
To study microorganisms, they need to be cultured.
They need to be provided with the conditions they need to reproduce quickly:
Bacteria and fungi can be grown in special media called agar.
This provides them with:
o Protein or amino…
In school and college laboratories, cultures should be incubated at a maximum temperature
This greatly reduces the likelihood of growth of pathogens that might be harmful to humans.
In industrial conditions higher temperatures can produce more rapid growth.
B1.2 Nerves and Hormones
The nervous system and hormones enable us to respond to external changes. They also help
us to control conditions inside our bodies. Hormones are used in some forms of contraception
and in fertility treatments. Plants also produce hormones and respond to external stimuli.
Receptors and the stimuli they detect include:
o receptors in the eyes that are sensitive to light
o receptors in the ears that are sensitive to sound
o receptors in the ears that are sensitive to changes in position and enable us to keep
o receptors on…
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