Unit 1.1 Keeping Healthy

Diet - Healthy balanced diet has the right balance of food types;

·         Carbohydrates - a source of energy for life processes.

·         Protein - growth and repair - building cells.

·         Fat - a source of energy for life processes: fats are also needed to make cell membranes and to insulate our bodies.

·         Mineral ions and Vitamins - neede in small amounts for healthy functioning of the body.

Inbalanced diets

·         Too little food = underweight

·         too much food = overweight

A poor diet may also lead to deficiency diseases. For example, little vitamin D in the diet can lead to rickets, which affects the proper growth of the skeleton. 

Exercise

If someone’s diet consists of food with a lower energy content than the amount of energy their body uses, the person will lose body mass.

Metabolic Rate

·         The speed at which chemical reactions take place in the body(cells)

·         Factors that can vary Metabolic Rate;

o    age

o    gender

o    inherited factors

o    Proportion of muscle to fat

o    Amount of exercise and physical activity

·         If you take in more energy than you use = excess stored as fat.

·         If you take in less energy than you use = decrease of BMI  

·         Eating a too much food = overweight or obese.

·         Eating too little food = underweight or anorexic

·         (Both forms of malnourishment.)

 Problems

Obesity can lead to serious health problems:

·         Arthritis

·         Type 2 diabetes (High blood sugar levels which are hard to control)

·         High blood pressure

·         Heart disease 

·         Obese people are more likely to die young. 

Anorexia can lead to health problems:

·         Menstrual cycle stopping

·         Tiredness

·         Weak bones

·         Deficiency disease       

Losing Weight

·         Reduce amount of energy you have, by cutting back the amount of food you eat. (Cut down on energy rich foods)

·         Increase the amount of energy you use, by doing more exercise.

·         The best is to do both - reduce your energy intake and exercise more. 

 You need some body fat to cushion your internal organs.

Inheriting health

Inherited factors are factors which we inherit from our parents

·         Appearance

·         Health

·         Metabolic rate

·         Cholesterol

Controlling Cholesterol

Cholesterol is an inherited factor which affects ones health.

Forms of cholesterol:

·         Healthy: Needed for cell membranes and vital hormones

·         Unhealthy: Can cause health problems

If the balance of the two is wrong you can risk having heart disease

The liver deals with the fat in your diet. A balanced diet can keep the balance correct, however the inherited factors can still have a big impact.

Exercise and Health

People who exercise regularly are generally healthier than people who don't do much exercise.

Why exercise keeps you healthy:

·         Less likely to be overweight - you will be using more energy

·         More muscle tissue - will increase metabolic rate

o   Controlling weight = less likely to be affected by: Arthritis, Diabetes and High Blood pressure

·         Cholesterol levels are affected by exercise. Exercise makes the good cholesterol go up and the bad cholesterol go down. This lowers the risk of heart disease and other health problems

Pathogens

-Are tiny micro-organisms that make us feel ill.

• Usually bacteria and viruses, which both once inside our body reproduce rapidly

Bacteria eneter our bodies the move inbetween our cells and release toxins. (damages our cells - making us feel ill)

Viruses enter our bodies and inject their DNA into our cells. The reproduce inside our cells untill our cells busrt. (damages our cells - making us feel ill)

1.4 Pathogens and Disease

Ignaz Semmelweiss (1818-65)

The doctor that discovered that disease were being transmitted through humans.

He demonstrated that hand-washing could drastically reduce the number of women dying after childbirth. This work took place in the 1840s, while he was Director of the maternity clinic at the Vienna General Hospital in Austria.

Stopping Pathogens

Our bodies prevent pathogens from getting into our bodies in two ways;

• Our skin - covers our whole body
• Mucus - Pathogens get trapped in the mucus then our stomach acids break them down.

Immune System

A system, including the thymus and bone marrow and lymphoid tissues, that protects the body from foreign substances and pathogenic organisms by producing the immune response.

White Blood Cells (WBC) are part of our immune system. They doo three things;

• Produce anti-toxins to counteract the toxins of pathogens
• Produce anti-bodies to help destoy particular pathogens
• Ingest pathogens - digest and destroy them.

Drugs

Painkillers - don't actually kill or affect pathogens they just relieve pain.

Antibiotics kill infective bacteria in the body.

• Penicillin is an example. Discovered in 1928 by Alexandra Flemming

Bacteria

Treatment = antibiotics

Bacteria live inbewteen body cells making them easier to treat than viruses.

Viruses

Treatment = vaccine

Reproduce inside our body cells. The virus inject its DNA into our cells and in the cells they reproduce untill the the cell bursts.

Usually our immune system overcomes the viral pathogens

Culturing microorganisms

The action of antibiotics and disinfectants can be investigated using cultures of microorganisms (populations of microorganisms that have been grown for a purpose). It is important that the cultures are uncontaminated by other microorganisms, so sterile conditions are needed:

• the Petri dishes, nutrient agar jelly and other culture media must be sterilised
• the inoculating loops used to transfer microorganisms must be sterilised (usually by passing the metal loop through a Bunsen burner flame)
• the lid of the Petri dish is sealed with sticky tape to stop microorganisms from the air getting in and contaminating the culture.

Growing Cultures

To grow cultures in a lab you must need;

• Liquid/gel containing nutrients - a culture medium. Contains carbs as energy source and other minerals. (Common medium used is called agar jelly)

• Warmth and Oxygen.

• Kept incubated at 25 degrees in school labs and at 35 degree in industry.(for safety - in school pathogens able to grow at 25 degree can't harm humans)

Pure Cultures

• Kill all bacteria on equipment. Metal loops through flame, boiling solutions + agar.
• Prevent microorganisms from air getting into the equipment.

• Some pathogens , particulaly viruses, can mutate (change) resulting in a new from called a mutation.

• Few people are immune to these changes so disease can spread quickly.

• Diseases that spread within a country are called an epidemic. Those that spreadacross counries are called pandemics.

MRSA

MRSA is the acronym for 'methicillin-resistant Staphylococcus aureus'. It's very dangerous because it's a strain of bacterium that is resistant to most antibiotics. To slow down or stop the development of other strains of resistant bacteria, we should always:

• avoid the unnecessary use of antibiotics
• complete the full course.

If you are immune to something this means you are not affected by a disease. 

How do we become immune?

The dead or inactive form of a pathogen is inserted in to your body. white blood cells produce antibodies which will recognise the antigen(protien shape). white blood cells known aslymphocytes help to protect you aginst disease such as producing anti-toxins which deactivate the antigen making it harmless .Lymphocyes produce antibodies and anti-toxins.  white blood cells know as phagocytes engulf (surrounding the bacteria) and then ingest the bacteria so you don't get the disease.

All vaccines have advantages and diadvantages.

Example;

• Measles
  • Causes long term damage to the body. (even death)

Some vaccines have side effects which may be mild or serious.

• Overuse of antibiotics leads to development of other bacteria strains.
• Doctors don't prescribe antibiotics for minor illnesss such as sore throats anymore.