Biological influences Factors that affect thought, feelings and behaviour Psychology Unit 3

Factors that affect thought, feelings and behaviour Genetics Heredity (nature) – involves the passing of characteristics from biological parents to offspring via genes at conception Influences many characteristics such as blood type, eye & hair colour, likelihood of developing certain diseases … Also influences the developmental rate of our brain and nervous system, brain chemistry and production of hormones All of these factors influence our behaviour

Genetics terms Heredity Biological characteristics passed on from parents to offspring through DNA Zygote Fertilised ovum: the result of the union of a sperm and egg cell Chromosomes 46 chromosomes in the human body: the full complement of DNA Genes The basic hereditary unit of DNA

Genetic terms Mitosis Cell division Results in the exact replication of a cell, the 2 daughter cells each containing the same DNA Meiosis The production of gametes ie. sperm and egg cells Each gamete contains 23 chromosomes, half the amount in other cells. The process produces unique gametes through crossing over and random variation

Hormones Hormones are chemical messengers secreted by endocrine glands. They travel through the bloodstream and affect other organs (including brain) When they act on the brain they regulate, influence and affect many different parts of the body, our emotions and even our behaviour Example: our interest in food, the female ovarian and menstrual cycle, our moods, our growth rate, our metabolism Hormones are slow-acting, compared to the nervous system

Specific endocrine glands Pituitary gland regulates many other glands in the body – the ‘master gland’ produces growth hormone, involved in puberty Adrenal glands produce adrenaline and noradrenaline – fight or flight response results in increased heart rate, blood pressure and breathing rate. also act as neurotransmitters also known as epinephrine and norepinephrine Thyroid gland produces thyroxin regulates metabolism

Psychoactive drugs Drugs Psychoactive drugs are chemical substances that affect the nervous system and brain activity They alter thoughts, feelings, perceptions and behaviours They generally target specific neurotransmitters They may be recreational or prescription drugs

Neurotransmitters: a review

Classification of recreational drugs Page 176 of textbook Depressants ‘Downers’ Calm the activity of the nervous system and slow body functions Stimulants ‘Uppers’ Excite the nervous system and arouse body functions Hallucinogens Change our perceptions and give us sensory images without input from the senses

Classify these recreational drugs Stimulant, depressant, hallucinogen Effect alcohol amphetamines caffeine cocaine ecstasy heroin ice (methamphetamine) LSD marijuana nicotine Alcohol Depressant Depresses the functioning of the cerebral cortex Effect More willing to be silly or aggressive, share our emotions; engage in behaviours that we wouldn’t if sober Disinhibition Amphetamines, methamphetamine, cocaine, ecstacy Stimulants Amphetamines, methamphetamine Increase levels of dopamine and norepinephrine in the brain Methamphetamine much stronger in its affect Cocaine Increases levels of dopamine, triggers pleasure centre Ecstacy Also a mild hallucinogen Euphoria and exhilaration; increased metabolism, heart rate, body temperature and sex drive; dilated pupils; drinking extreme amounts of water (ecstacy) Amphetamines used to treat ADD and ADHD Heroin (opioid from poppy seed) Intense pleasure; pain relief; relaxation, drowsiness and clumsiness; confusion; slurred/slow speech; slow breathing & heart rate LSD (ergot fungus), marijuana (plant) Hallucinogens Affect serotonin activity in the prefrontal cortex Rapid emotional shifts, from fear to euphoria; increased blood pressure, heart rate & body temperature; dizziness, sleeplessness; numbness, weakness & tremors All recreational drug suppress appetite.

Scenario: group work WA Health Dept. Records show that the numbers of young people 14-17 years old taken to emergency departments in the metro area after taking drugs or alcohol has increased significantly fro 2008 to 2013. The number of 14 year olds has increase by 21%, the number of 15 year olds by 39%, 16 year olds by 26% and 17 year olds be 21%

Questions: group work What could be a possible hypothesis to explain the observed increase in the number of young people being taken to hospital emergency departments as a result of their intake of drugs or alcohol? Describe how each of the following drugs might affect the person’s body chemistry and therefore change their behaviour, in the short term as well as the long term Marijuana Ecstacy Methamphetamine (ice)

Prescription drugs: Anti-depressants Two main categories of anti-depressants: Increase the amount of norepinephrine (noradrenaline) and serotonin released at the synapse. Inhibit the enzyme that breaks down the neurotransmitters or block the re-absorption of the neurotransmitters into the pre-synaptic knob.

Prescription drugs: antipsychotics Work to damp down responses to irrelevant stimuli that cause hallucinations, delusions and the disordered thoughts of schizophrenics Most attempt to block synaptic receptors in the brain’s dopamine pathways