Basic background on genes
Genes are made up of chromosomes which are made up of DNA - Deoxyribonucleic acid. Every human has 23 pairs of chromosomes, 23 from mum and 23 from dad making a total of 46. This means that 50% of our genetic make-up is from dad and the other 50% is from mum.
We also share 50% of our genetic material with our sisters and brothers, and 25% with our maternal uncle or auntie.
Boys genes - XY
Girls genes - XX
Dominant gene - a strong gene, you will defiantly inherit this characteristic.
Recessive gene - two of these genes are needed in order to inherit the characteristic.
Key assumptions -
- The influences of genes on behaviour
- The influence of the nervous system on behaviour
1% of the population has Schizophrenia (SX) at any one time. If one parent has the illness then the offspring’s chance of developing SX increases to 10%.
The nervous system is made up of 6 parts:
However, for exam only need to remeber the brain and the spinal cord.
Neurons in the brain
Neurons in the brain are made up of:
- Myelin Sheath
- Synaptic bulbs
Neurons in the brain are arranged head to tail, however, one neuron does not touch the next, and there is a small gap between each neuron. This is called the synapse. Messages are passed from one neuron to the next using electricity and neurotransmitters.
How do they work?
Action potential (impulse) travels down the presynaptic neuron (the first neuron). Vesicles containing neurotransmitters move to the surface of the presynaptic bulb. The neurotransmitter is released into the synaptic cleft (the small gap between the neurons). The neurotransmitter is absorbed through the receptor of the post synaptic neuron (the second neuron).
The action potential carries on along the post synaptic neuron. Not all of the neurotransmitter is absorbed by the post synaptic neuron, some is broken down in the synaptic cleft by enzymes. Some is pumped back into the presynaptic neuron, where it is broken down and re-used, this is called re-uptake pump.
What are neurotransmitters?
Chemicals released by specific neurons in the brain to control behaviour.
Norepinephrine - is associated with alertness and energy
Dopamine - is associated with attention, motivation, pleasure and reward
Can these cause problems?
Excess Dopamine causes Schizophrenia which includes symptoms such as hallucinations. Too little of the neurotransmitters Serotonin is linked to depression.
Animal Lab Experiments and Normal Lab
Normal Lab experiment and Animal Lab experiment similarities:
- Both are conducted in artificial environments
- The independent variable is manipulated by the researcher
- The dependent variable is measured
- Quantitative data is collected
- Participants and animals are randomly allocated to conditions
Advantages of Animal Experiments
- Most animals are small and easy to handle, this means that they can be manipulated
- When studying genes it is easier to use animals as you can reproduce more than one generation in a short time, this means you can measure the effects of the drugs/treatment of genes in offspring.
- Some animals such as mice have similar brain function and chromosomal functions as humans, this makes it easy to compare animal results to humans.
- Using animals can have some benefit to them also, as we can learn more about the species and thus can develop and improve care for them in zoos or outside environments.
- When studying age is is easier to use rats for example as they only live for about 2 years and monkeys 15-20 years whereas we live 80+ years. Researchers can obtain results sooner as these animals have shorter life spans, also by the time the participant dies the researcher would of probably also.
Disadvantages of Animal Experiments
- Animals are not exactly the same as humans, despite having similar functions in the brain and chromosomes. It will be difficult to generalise the results as animals brains are not exactly identical to that of humans.
- In order to study genetic disease - such as Parkingsons, the disease has to be artificially reproduced in animals, this is not the same as a human developing it.
Guidelines for animal studies
There are many guideline for the use of animals in studies, here is a few:
- Caging and social environment must suit the species
- there should be a reasonable amount of time between experiments so animals have time to recover and rest
- if the animal is going to be deprived then the animal must be monitored and suffering must be kept to a minimum
- Anaesthetic must be given, blood pressure and heart rate must be monitored to understand the pain involved and researchers must take action to alleviate the pain or end the experiment
- no more animals should be used than necessary
- alternatives to animals should always be sought
- Restraints that animals cannot easily adapt to should only be used if there is no alternative
- living animals shall only be used when necessary
Bateson Cube 1988
This cube is used in order to see whether an animal study should be carried our or not. It is a model of cost-benefit analysis.
The cube evaluates on three criteria:
- The degree of animal suffering
- the quality of research
- the potential medical benefit
If the researcher does not meet high standards on each of these three then the study shall not be carried out.
Ethical advantages to using animals
- Animals can be used in the place of humans as some guidelines effect humans but not animals, for example Lesions - damage to the brain structure and Ablation -removal of part of the brain.
- Pro-speciesism suggests that we ought to do all we can to protect our own species.
- Drugs have been developed that may of not happened if animal testing was banned.
- The knowledge obtained can also benefit the species as we can learn more about them.
Ethical disadvantages to using animals
- Almost all animals feel pain.
- Animals in experiments are not in their natural environment and are in an unfamiliar one, and therefore could be distressed because of this.
- Animals should be treated ethically; they are not sufficently different from humans, they should not be treated like objects.