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Fitness and Health

Systolic Pressure:Max pressure the heart produces Diastolic Pressure: between beats 
Increase blood pressure:Stress, high alcohol intake, smoking, being over weight
Decrease blood pressure:Balanced diet+ regular exercise
What can high blood pressure cause? Blood vessels to burst, stroke, damage to kidneys
What can low blood pressure cause? Dizziness, fainting, poor circulation
Fitness=ability to do physical activity
Health=being free from diseases caused by bacteria etc.

Smoking: carbon monoxide decreases the oxygen carrying capacity in the blood, it combines with haemoglobin,preventing it from combining with oxygen, causes the heart rate to increase
Diet and Heart Disease:
Heart disease is caused by a restricted blood flow to the heart muscle, the risk can be increased by: high levels of saturated fat in the diet(build up of cholesterol),high levels of salt in diet

The narrowing of arteries caused by plaques in the coronary artery can reduce blood flow to the heart muscle. The plaques increases the chances of thrombosis and blood clots also  

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Human Health+Diet

A balanced diet:
Carbohydrates made up of simple sugrs and stored in the liver as glycogen or converted to fats 
Proteins made up of amino acids, essential for growth and repair, cannot be stored
Fats made up of fatty acids and glycerol,stored under the skin and around organs as apidose tissue

Protein Intake: EAR=0.6 x body mass in kg
Too little protein in the diet can cause the condition: kwashiorkor
The EAR may be affected by body mass, age, pregnancy, breast feeding(lactation)
First class proteins:From meat and fish, contain all the essential amino acids
Second class proteins:From plants, do not contain all the essential amino acids

BMI=mass in kg
      (height in m)2
30=obese 25-30=overweight 20-25=normal 20-=underweight  

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Staying Healthy

  • Malaria is cause by a protozoan called plasmodium, which feeds on red blood cells,carried by mosquitoes(vectors-not affected by disease) and transmitted by a mosquito bite
  • Parasite: an organisms that lives off/in another organisms causing it harm, knowing it's lifecycle can stop the spread of malaria, drain the water and spray insectsides 
  • Pathogens(cause disease) produce symtoms by damaging the cells or producing waste called toxins, the body protects itself by producing antibodies which lock onto antigens on the surface of pathogens, killing it 
  • Passive immunity: vaccinations, quick but has a short term effect, active immunity: body produces antibodies, slow process, long lasting 
  • The process of immunisation: injecting a harmless pathogen with the right antigens, white blood cells produce the right antibodies, memory cells remains in the body providing immunity
  • Antiviral drugs:against viruses, slow down the pathogens development 
  • Antibiotics: against bacteria and fungi, kills pathogen  
  • A placebo pill is harmless, used as a comparison in drug testing 
  • A blind trial: the patient doesnt know whether they are recieving a placebo or the drug 
  • A double blind trial: the doctor or the patient doesnt know which drug is being used 
  • Excessive use of antibiotics has led to resistant forms of bacteria e.g. resistant MRSA 
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The Nervous System

Eyes: Cornea and lens refract light, retina: contains light receptors, which are sensitive to different colours

Binocular vision:helps to judge distance by comparing images in each eye, the more different the nearer the object is

Acccommodation:altering the shape on the lens to focus on near or distant objects 

Distant:cilary muscles relax, suspensory ligament contract-lens becomes less rounded
Near:cilary muscles contract, suspensory ligament relax-lens becomes more rounded 

Faults in Vision:
Red-green colour blindness is caused by lack of specialised cells in the retina
Long sight:eyeball is too short, lens is too thin,image is focused behind the retina-convex
Short sight:Eyeball is too long, lens is too round,image is focused infront of the retina-concave

Nerve Cells-neurones, nerve impulses pass along the axon,gap between neurones=synapse

Reflex arc:stimulus-receptor-sensory neurone-CNS-motor neurone-effector-respons
Spinal reflex:receptor-sensory neurone-relay neurone-motor neurone-effector 

Neurone adaptions:long, have dendrites to pick up impulses,insulator sheath
Arrival of an impulse triggers the realese of a transmitter substance which diffuses across the synapse, the transmitter substance binds with receptor molecule in membrane of next neurone

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Drugs and You

Why do drugs have a classification? To show how dangerous the drug is and to decide what the penalty would be.

Types of drugs:

  • Depressant(alcohol)-block the transmission of nerve impulses across the synapse by binding with the receptor molecules in the memberane of the next neurone 
  • Painkillers(paracetamol)
  • Stimulant(caffeine,nicotene)-casue more neurotransmitter substances to cross the synapse 
  • Performance enhancers(anabolic steroids)
  • Hallucinogens(LSD)

Effects of smoking:
Cilla(tiny hairs) are found epithelial lining of the trachea, bronchi.
A smokers cough- result of dust and particulates collecting and irritating the epithelial lining and mucus not being moved by the cilia 
Effects of alcohol:
Cirrhosis of the liver-liver gets damaged when it break down toxic chemicals  

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Staying in Balance

Homeostatis:keeping a constant internal environment involves balancing bodily inputs/outputs
Negative feedback systems are used to cancel out a change for example a decreasing temperature level.
High Temperature:
Can cause: heat stroke and dehydration
To avoid: sweating increases-increases heat transfer from the body to the environment,the evaporation of sweat requires body heat to change the liquid sweat into water vapour. Vasodialation:widening of blood vessels this causes more blood flow near the surface of the skin, resulting in more heat transfer 
Cold Temperature:
Can cause: hypothermia
To avoid: vasoconstriction: the narrowing of blood vessels meaning there is less blood flow near the surface and less heat transfer 
Blood temperature is monitored by the hypothalamus gland
Controlling Blood Sugar Levels: The hormone, insulin control blood sugar levels 
Type 1: pancreas doesn't produce any insulin-fixed by doses of insulin
Type 2: body doesnt react to insulin or produces too little-fixed by diet
Insulin regualtes blood sugar levels by converting excess glucose into glycogen-stored in liver 

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Controlling Plant Growth

Phototropism: a plants growth response to light  Geotropism: a plant growth response to gravity
Shoots are positively phototropic and negatively geotropic
Roots are negatively phototropic and postively geotropic 

Auxins:group of plant hormones that move through the plant in solution
They are made in the roots and shoot tip
When the shoot tip is removed the shoot does not grow
Different amounts of auxins are found in different parts of the shoots when the tip is exposed to light. More auxins are found in the shady parts of the shoots, a higher amount of auxins will increase the length of cells. Therefore the increase in cell length on the shady side of the shoot causes curvature of the shoot towards the light.

Commercial Uses of Plant Hormones:

  • selective weedkillers 
  • rooting powder
  • delay or accelerate fruit ripening  
  • to control dormancy in seeds 
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Variation and Inheritance

Some characteristics can be dominant or recessive, dominant alleles are expressed when present but in the absence of the dominant allele, the recessive allele is expressed. 
Allele:different version of the same gene

  • Human cells have 23 pairs of chromosomes
  • Sex chromosomes: XX-female XY-male
  • Genetic variation is casued by: mutations,rearrangement of the genes during formation of the gametes, fertillisation 

Monohybrid Cross: involves one pair of characteristics controlled by a single gene, one allele being dominant and the other recessive. Homozygous:having identical allele Hetrozygous:different alleles Genotype:genetic make up Phenotype: the alleles expressed 

Inherited Disorders: casued by faulty genes,most of which are recessive  
Ethical Issues rasied:

  •  in deciding to have a genetic test 
  • by knowing the risks of passing an inherited disorder on(may stop you from getting married)
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