Diet and Exercise
Diet
Regular exercise and a balanced diet are needed to keep the body
healthy.
Insufficient food leads to a person being underweight and prone to
illness.
Too much food and not enough exercise leads to a person being overweight
and get other illnesses.
Nutrient
Carbohydrates- Source of Energy
Fats- Source of Energy + for insulation
Proteins- for Growth and repair, Building cells in our body
Mineral ions + Vitamins - For healthy functioning of the body
Imbalanced Diet- Causes a person to be malnourished,
Too little food - underweight
Too much food - overweight
May also lead to deficiency diseases
Exercise
Metabolic rate Speed in which chemical reactions happen in our body.
Affected by:
- Proportion of muscle and fat
in the body
- Amount of exercise
- A higher muscle : fat ratio
= higher Metabolism
- Exercising= higher
Metabolism
Other factors that affect health include:
Inherited factors e.g. blood cholesterol level
Pathogens
Pathogens are micro-organisms that cause diseases.
Bacteria
Microscopic living cells which can multiply rapidly in the body.
They release toxins that make us feel ill.
Diseases caused by Bacteria include: Food poisoning, cholera and
typhoid.
Viruses
They are smaller than bacteria and have a protective protein coat that
surrounds a genetic material.
They reproduce inside host cells and damage them when they do this.
They multiply inside the host cell and filling and burst it opens
passing out into the blood.
Diseases caused by viruses include: Flu, colds, measles, mumps and rubella.
White blood cells
They can either ingest pathogens, destroying them
Or
Produce antibodies to destroy specific pathogens
Produce antitoxins to counteract the toxins released by
pathogens
Lymphocytes release antibodies bind to antigens on pathogens which
clumps them or damage/destroy them
Each lymphocyte produces a specific type of antibody which fit in a
certain antigen.
When a lymphocyte releases the correct antibody, they reproduce very
quickly and make many antibodies.
Phagocytes ingest pathogens.
Vaccination
Causes body to produce enough white blood cells to protect against a
pathogen.
Antibiotics are effect against bacteria but do not work for viruses.
Vaccines contain:
Live pathogens which are harmless
Harmless fragments of the pathogens
Dead pathogens
These all act as antigens,
They stimulate white blood cells to produce antibodies against the
pathogen.
If the person gets infected with the real pathogen, their body can
respond faster.
Hygiene
In the 19th century, Ignaz Semmelweiss realised the doctors should wash
their hands before examining patients which greatly reduced the number of
deaths
Medicines
Painkillers relieve the symptoms of diseases but don’t kill pathogens
E.g. Paracetamol.
Antibiotics kill bacteria or stop their growth, does not work against
viruses, Penicillin was the first antibiotic discovered by Alexander Fleming.
Antibiotic resistance
Bacteria strains can develop resistance to antibiotics, this happens
because of natural selection.
In a large population of bacteria,
Antibodies kill individual pathogens of the non-resistant strain
Resistant individual pathogens survive and reproduce.
Population of resistant pathogens increases
MRSA is a one of them. To avoid this happening we should avoid the
unnecessary use of antibiotics and complete the full course of prescription
given by the doctor.
Growing micro-organisms
We can investigate actions of antibiotics and disinfectants using
cultures of micro-organisms (Population of micro-organisms that have been grown
for a purpose)
Important that cultures are not contaminated by other micro-organisms so
sterile conditions are needed:
Petri dishes, agar jelly must be sterilised
Inoculating loops sterilised (passed through Bunsen burner flame)
Safety
Dangerous to incubate cultures close to 37 degrees Celsius as it might
allow growth of pathogens harmful to health. Max used in schools is 25 degrees Celsius.
Higher temperatures are used industrially to speed it up.
No comments:
Post a Comment