The nervous system
They are specialised for communication between other neurons, muscles and organs in the body.
When two neurones connect, this is called a synaptic transmission.
A synapse is a specialised cell that allows electrical messages to transfer to an adjacent neurone. Neurones don’t actually touch at the synapse, electrical impulses jump between cells at what is called the synaptic cleft.
Too much hormones transmitted by the neurones are called excitatory neurons. If it is too slow then this is called the inhibitory neurons.
Neurotransmitters are known to have an effect on behaviour and mental processes.
Sensory, motor and interconnecting neurons
There are three different types of neurons which send certain messages across the body.
Type of neurone
They receive messages from the senses (the external environment) and send them to the Central Nervous System- the spine (CNS).
They receive messages from the brain and the spinal cord and take them to appropriate organs and muscles.
These are found in the eyes, the brain and the spinal cord. They receive messages from the sensory neurons and pass messages onto other connecting neurons or motor neurons.
The nervous system diagram
The brain stem controls basic (e.g. sleeping and walking) and bodily (e.g. heart rate and breathing) functions.
The cerebellum, this controls balance and movement. If this is damaged then more than likely people will be clumsy with poor coordination.
The cerebral hemispheres are used for a much higher function, such as vision and memory.
The spinal cord receives messages to and from the brain which connects to the nerves in the peripheral nervous system.
The peripheral nervous system
SOMATIC NERVOUS SYSTEM: This transmits information from the five senses through the receptors to the central nervous system (CNS). It receives information from the central nervous system (CNS) instructing muscles to act.
AUTONOMIC NERVOUS SYSTEM: This governs the smooth muscle of the internal organs and controls the involuntary functions of the body.
Blood vessels of internal organs.
The Brain in more depth
Cerebellum controls balance and movement. Damage to this would lead to clumsiness and poor coordination.
Cerebral hemispheres coordinate higher functions such as vision and memory.
At the FRONT there is the frontal lobe which is used for motor processing. It involves higher thought processes such as movement and reasoning.
Damage would result in a lack of insight, lack of involuntary reflex and inability to adjust behaviour.
Broca’s area (closest to the frontal lobe) is used for speech production and converts memories and thoughts into speech.
The Brain in more depth continued...
Damage would result in a language disorder such as aphasia, where the speech is not fluent and slow.
Parietal lobe – maybe referred to as the somatosensory area. This processes sensations from the skin and muscles.
Damage would lead to an inability to recognise whole objects by sight and a delay in reactions. E.g. sensory neuronàspineàparietal lobeàaction.
Temporal love which is the auditory area and it is important for hearing, language and memory.
Damage would lead to a specific weakness in language and memory will be affected.
Wernicke’s area (located near the ear) shows functions such as speech comprension and recognition.
Damage would result in a difficulty in understanding speech.
Occipital lobe is known as the visual area. This is where the process of visualisation occurs.
Damage would cause visual sensory neglect in the visual field of the opposite side.
Fight or flight response
The sympathetic branch of the autonomic nervous system stimulates fight or flight response to threatening situations and the parasympathetic branch returns the body to its normal state.
The fight-or-flight response (also called the fight, flight, freeze, or fawn response in post-traumatic stress disorder, hyperarousal, or the acute stress response) is a physiological reaction that occurs in response to a perceived harmful event, attack, or threat to survival.
Adrenaline and Stress
Hypothalamus secretes CRFàthis stimulates pituarity gland to release ACTHàcarried around the blood stream where it stimulates the adrenal medulla which releases adrenaline.
Stress is a biological and psychological response experienced on encountering a threat that we feel we do not have the resources to deal with.
A stressor is the stimulus (or threat) that causes stress, e.g. exam, divorce, death of loved one, moving house, loss of job.
Sudden and severe stress generally produces:
- Increase in heart rate
- Increase in breathing (lungs dilate)
- Decrease in digestive activity (don’t feel hungry)
- Liver released glucose for energy
Advantages & Disadvantages of a Post mortem scan
Post mortem: a neurobiological research method in which the brain of a patient with a disorder/abnormality is examined after death.
+ It can establish cause of death and show abnormalities that may have affected their lfife.
It is hard to establish cause and effect.
Obtaining a brain following a person’s death is difficult.
Many people don’t consent to the medical studies.
- Don't know if they had earlier damage.
Advantages & Disadantges of an EEG scan
EEG: Electrodes are attached to the scalp and connect to a recording device. This then translates the electrical activity of the brain to a trace.
+ Helps to understand their activity in an epileptic fit.
+ They are alive.
-It doesn't tell you the precise function of the neurons involved.
Advantages & Disadvantages of a PET scan
PET: Glucose is needed by all the neurones to provide energy for bodily function. The more active the cell, the more glucose was absorbed. They injected the radioactive glucose into the bloodstream.
+ Location of brain activity is precise.
+ Allows researchers to view brain activity when the patient is alive.
-Invasive as it introduces substances to the body.
Advantages & Disadvantages of a CAT and MRI scan
CAT: Measures tissue density and detects any difference in this.
+ Shows where major damage is; e.g. a tumour.
+ It is non-evasive.
MRI: Uses a magnetic field which causes the nuclei of the brain cells to line up.
+ It is non-evasive.
+ Monitoring a live brain.
The biological approach
ASSUMPTIONS: Biological processes: genes, neurochemistry and the nervous system.
GENETIC BASIS OF BEHAVIOUR: Twin + family studies.GENOTYPE + PHENOTYPE: interaction between nature + nurture
EVOLUTION + BEHAVIOUR: natural selection of genes based on survival value and, ultimately, reproductive success.
Scientific methods: precise
techniques, such as scanning
techniques, family studies, drug trials
Casual conclusions: drugs may only
be associated with symptom
reduction, not causes
The endocrine system
endocrine system= instructs glands to release hormones directly into the bloodsteam
glands & hormones: Hormones are chemical substances that circulate in bloodstream + only affect target organs. Glands synthesise substances e.g. hormones. Pituitary is master gland.
fight or flight: Sympathetic arousal adrenal gland to adrenaline.
genotype: genetic make-up
phenotype: the way genes are expressed through physical, behavioural and psuchological characteristics.
The biological approach
What is bio-approach?
- Looks at biological theories of gender development, key issues of interest
- Combines psychology & biology to provide psychological explanation for human behaviour from basic differences between male and female. Such as language, memory & perception.
- Nature vs Nurture
- Nature: our beh. is determined by our biological genetic make-up
- Nurture: Influences of the environment
- Identical twins come from the same egg – Non identical twins don’t.
- Monozygotic (MZ) (Identical) have the same DNA
- Dizygotic (DZ) (Non-Identical) have different DNA
- Look at twins through to see what traits they have by looking at concordance rates)
- E.G. There is a high concordance rates for MZ twin’s
Biological factors in gender development
- 23 chromosomes from each parent
- 22/23 determine our physical appearance
- Final pair determines our gender
- In females, the final pair of chromosomes is: **
- In males, the final pair of chromosomes is: XY
- Foetus inherits the X chromosome from mother and Y chromosome from father.
- 6 weeks into development the gonads (sex organs) develop, but at this point there is still no difference.
- A gene in the Y chromosome called SRY produces a “testis-determining factor” which turns the developing gonads into testicles rather than ovaries
- Default setting for all foetuses is to develop into a female unless there is a Y chromosome.