Biology B1

Blood pressure

• Systolic (arteries contract)
• Diastolic (arteries relax)

Factors that increase blood pressure:          Factors that decrease blood pressure:

• Being over weight                                   Regular exercise
• Stress                                                      Balanced diet
• High alcohol intake
• Smoking

Consequences of high blood pressure:       Consequences of low blood pressure:

•  Vessels can weaken and burst              Dizziness
• Lead to kidney failure                              Fainting

Health and Fitness

Being healthy means being free from disease and being fit is the amount of physical exercise you're capable of. Ways of measuring fitness:

• Strength
• Stamina
• Flexibility
• Agility
• Speed
• Cardiovascular efficiency

Smoking

Smoking causes:

• Cancer
• Heart disease
• Emphysema
• Birth weights
• Bronchitis

Smoking damages the cilia which line the airways. This prevents cilia from being able to remove mucus, tar and dirt from the lungs leading to a 'smokers cough'.

How smoking increases blood pressure:

• Carbon monoxide reduces the oxygen carrying capacity of red blood cells because it combines with haemoglobin preventing oxygen transport
• Nicotine increases the heart rate

Heart disease

Factors that increase heart disease:

• High blood pressure
• Smoking
• Too much salt
• High fat diets

A balanced diet

• Carbohydrates are made up of simple sugars.
• Fats are made up of fatty acids and glycerol.
• Proteins are made up of amino acids.

A balanced diet will depend on: Age; Gender; Activity; Religion; Personal choice; Medical reasons.

Storage of Molecules

Carbohydrates are stored in the liver as glycogen or converted into fats. Fats are stored under the skin and around organs as adipose tissue. Proteins are not stored.

Proteins

Kwashiokor is common in developing countries due to :

• Overpopulation
• Limited investment in agricultural techniques

First class proteins come from animals and contain essential amino acids. Second class proteins are from plants.

Malaria

A mosquito (the vector) sucks blood from a human. If malaria parasites are in the blood they mate and move from the gut to the salivary glands. The mosquito bites another person and the parasites move to their blood stream. Malaria parasites move to the liver where they mature and reproduce. They migrate to the blood and causes red blood cells to burst open.

Ways to reduce malaria:

• Sleeping under mosquito nets
• Using insect repellent
• Killing mosquitos with insecticides

Immunisation

Harmless pathogen is injected which carries antigens. Antigens trigger immune response by white blood cells which produce antibodies. Immunity remains.

Passtive immunity occurs when antibodies are directly injected straight into an individuals body when a quick response is needed.

Benefits and risks of immunisation:

• Protects against disease which could kill or cause a disability
• If everybody is vaccinated the disease will eventually die out.
• An individual could have a bad reaction
• No vaccination is 100% safe.

Testing new drugs

Antibiotics are used to treat diseases caused by bacteria or fungi, antiviral drugs are used to treat diseases caused by viruses.

Doctors must only prescribe antibiotics when necessary as some bacteria can become resistant to antibiotics such as MRSA.

A drug can be tested using:

• Computer models to…