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

2. 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

3. 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

4. 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

5. 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

6. 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

8. 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

9. Neurotransmitters: a review

10. 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

11. 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.

12. Scenario: group work
WA Health Dept. Records show that the numbers of young people years old taken to emergency departments in the metro area after taking drugs or alcohol has increased significantly fro 2008 to 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%

13. 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)

14. 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.

16. 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