Biology B1

Biology B1

Fitness and blood pressure
1. Fit and healthy
  1. Healthy means being free of diseases
  2. Fit is how well you can perform physical tasks
  3. Fitness
    1. Can be measured through...
      1. Strength
      2. Speed
      3. Agility
      4. Flexability
2. Blood pressure
  1. Blood is pumped around your body by contractions of your heart
    1. It leaves your heart and then flows around your body through arteries
      1. It then flows back to your heart through veins
  2. Healthy blood pressure should be about 135 (systolic) and 85 (diastolic)
  3. Factors that increase your blood pressure...
    1. Smoking
    2. Being overweight
    3. Too much alcohol
    4. Being under lots of stress
  4. Low blood pressure
    1. It causes poor circulation which means that tissues don't get enough food and oxygen
    2. You could end up feeling dizzy and fainting
High blood pressure and heart disease
1. Smoking
  1. Smoking raises blood pressure
  2. Chemicals
    1. Carbon monoxide
      1. It combines with the haemoglobin in red blood cells, and so reduces the amount of oxygen they are able to carry
    2. Nicotine
      1. Increases heart rate
2. Poor diet
  1. Saturated fats
    1. Cholesterol is a fatty substance
    2. You need some cholesterol for making cell membrains
    3. Too much forms plaques on the artery walls which narrows the arteries and restricts the flow of blood
  2. High salt levels
    1. You need some salt but too much can cause high blood pressure
    2. It causes damage to the arteries, which can lead to a heart attack
3. Narrow arteries
  1. The heart gets blood from the coronary arteries
    1. If these become narrowed the heart gets less oxygen
      1. A thrombosis (blood clot) restricts blood flow
        If a blood clot happens in a narrowed artery, the blood flow might be cut off completely
        This causes a heart attack
Eating Healthily
1. Balanced diet
  1. Carbohydrates
    1. Provide energy
  2. Fats
    1. They provide energy, act as an energy store and provide insulation
  3. Protiens
    1. They are needed for growth and repair of tissue
  4. Vitamins and Minerals
    1. They have various functions
      1. Vitamin C prevents scurvy
      2. Iron is needed to produce haemoglobin
  5. Water
    1. To prevent dehydration
2. Needs may vary
  1. Age
    1. Children need protein for growth
    2. Old people need calcium to protect against bone diseases like osteoporosis
  2. Physical activity
    1. More active people need more carbohydrates for energy
  3. Gender
    1. Females need iron to replace iron lost during the menstrual cycle
3. Different diets
  1. Religious reasons (e.g. Hindus don't eat cow because they are sacred)
  2. Personal reasons (e.g. Vegetarians don't eat meat because they think that it is cruel)
  3. Medical reasons (e.g. some people may be allergic to some foods)
Diet problems
1. Not enough protien
  1. Causes kwashiorkor
    1. A common symptom is a swollen stomach
  2. In developing countries many people have diets that are too low in protein
    1. Overpopulation - there just isn't enough protien-rich food for everyone
    2. Money - there isn't enough money to invest in proper agriculture
  3. E.A.R.
    1. EAR (g) = 0.6 x body mass (kg)
    2. Estimated average daily requirement of protein
    3. It is just an estimate
    4. EAR varies with age, (e.g. children need more protein because they are still growing
    5. Pregnant women need extra protein to help their baby grow
2. Eating disorders
  1. Anorexia nervosa
    1. It leads to self-starvation
  2. Bulimia nervosa
    1. It involves binge eating followed by self-induced vomiting
3. BMI
  1. BMI isn't always reliable, muscle weighs more than fat so people with lots of muscle may come out with a high BMI
  2. BMI = Body Mass Index
  3. BMI = body mass (kg) over height (m) squared
  4. Weight descriptions
    1. Below 18.5 - underweight
    2. 18.5 - 24.9 - normal weight
    3. 25 - 29.9 - overweight
    4. 30 - 40 - moderately obese
    5. Above 40 - severely obese
  5. BMI is used to decide if someone is underweight, normal, overweight or obese

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	Created by Lara Coffin almost 11 years ago