Nervous system: provides the biological basis for psychological experience
Nervous system is divided into central nervous system and peripheral nervous system
Central nervous system compromises the brain and the spinal chord
Peripheral nervous system is the nerves outside the brain and the spinal chord
Central Nervous System
Central nervous system: concerned with all life functions and psychological processes
The brain controls many of the body's functions including sensation, thought, movement, awareness, and memory.
Brains main job is to ensure that life is maintained. involved in higher functions and psychological processes
Different parts of the brain. Some more primitive and concerned with vital functioning other parts involved in higher order thinking. Like planning
Central Nervous System 2
Spinal cord receives and transmits info to and from the brain to teh PNS. Fluctuates the transferal of messages to and from the brain to pns. Also involved in reflex actions
The spinal cord connects to the brain via the brain stem and then runs down through the spinal canal located inside the vertebra.
The spinal cord carries information from various parts of the body to and from the brain. Some reflex movements, responses are controlled by spinal pathways without involvement from the brain.
Involved in reflex actions such as the startle response.
Peripheral Nervous System
PNS includes all of the nervous system throughout the rest of the body
Extends beyond CNS and transmits messages to whole of body from brain and messages from whole of body to brain
PNS is divided into the somatic system and the autonomic system
Autonomic system: transmits and receives info from internal organs to sustain life processes
Somatic system: transmits and receives info from the senses like visual and auditory info. to and from central nervous system. Also directs muscles to react and move.
Peripheral Nervous System 2
Autonomic system is divided into sympathetic system and para sympathetic system.
Parasympathetic nervous system: conserves the bodes natural activity levels by decreasing activity or maintaining it.
Sympathetic nervous system: increases bodily activities
endocrine system= all of the hormones and all of the glands that release that hormone.
The endocrine system is made up of glands that produce and secrete hormones, chemical substances produced in the body that regulate the activity of cells or organs.
endocrine system has a series of glands which release chemicals (hormones)throughout the body via the blood and other bodily fluids.
endocrine responses are slower than autonomic nervous system as hormones travel via blood= slower
Endocrine System 2
pituitary gland = ‘master gland’. controls whole of endocrine system. also monitors it.
during a stressful situation, pituitary gland releases ACTH(the main stress hormone) this hormone travels through the blood to reach the adrenal glands. adrenal medulla then releases adrenaline.
specialist glands in the body which form part of this system.
adrenal gland= adrenaline
Endocrine System 3
behaviour is thought to be influenced by hormones. each hormone thought to affect behaviour in a different way.
pituitarygland - some of hormones released important for regulating endocrine system. ‘master gland’
Adrenal gland - important part of the fight-or-flight response as it facilitates the release of adrenaline
Overies - facilitate the release of oestrogen and progesterone
Testes- facilitate the release of testosterone
The hormone oxytocin, released by the pituitary gland, is thought to be important for reproductive behaviour. High levels of oxytocin encourage strong bonding between couples. This is also the case for mother/child bonding
Fight or flight response generated from the autonomic nervous system. specifically sympathetic branch
It is a reflex response designed to help an individual manage physically when under threat
Also activated at times of stress because body percieves stress to be a threat.
Fight-or-Flight helps individuals to react quicker than normal
It facilitates optimal functioning so that the individual can fight threat or run away from it.
Fight-or-Flight response. 2
The Fight-or-Flight response involves two elements that work simultaneously. Fast autonomic response and a slow endocrine response.
It occurs in a series of steps:
Hypothalamus recognises that there is a threat
It then sends a message to the adrenal gland (adrenal medulla)
This triggers the release of adrenaline to teh endocrine system and noradrenaline in the brain.
This then prompts physical changes such as,
Increased heat rate, faster breathing rate, muscle tension, pupil dilation, the production of sweat, reduced functioning of teh digestive and immune systems.
Physical changes help individual to fight or run away from potentially threatening situation.
Fight-or-Flight response. 3
When a stressor is detected by Hypothalamus, Autonomic nervous sytem is initiated. Pituitary gland is also stimulated which then triggers the endocrine response.
Physical changes prompted because...
Increased heart rate - to speed up the blood flow to vital organs and improve spread of adrenaline around body.
Faster breathing rate- to increase oxygen intake
Muscle tension- to improve reaction time and speed
Pupil dilation- to improve vision
Production of sweat- to facilitate tempreature regulation
Reduced functioning of digestive and immune systems - to save energy for prioritised functions such as running.
Fight-or-Flight response. 4
Sypathetic branch in Fight-or-Flight response prepares body for action
Parasympathetic branch restores body back down to normal.
Symphathetic INCREASES bodily activities
Parasymphathetic DECREASES bodily activities
Biological structures EVALUATION
Assessing extent to which biological structures affect behaviour can be difficult
Can be argued that they are tools to make behaviour happen and not the cause
Cause and effect not established in most research because much of research is corrolational
Means that only teh relationship between biological influence and the behaviours can be investigated
People respond to stressors in different ways according to personality types
Biological structures that underpin behaviour can be seen as REDUCTIONIST
It attempts to reduce human behaviour and cognitive processes down to biological processes
It is too simplistic. Within biological processes there is a further reduction down to a specific component. Like the level of a hormone.
Physical nature of bodily systems means that research is scientific. measures are objective. This increases the reliability of the results.
Connection between biological structures and human behaviours HAS been established
A neuron is a specialised nerve cell that receives, processes, and transmits information to other cells in the body.
A neurone is specialised for communication
Fixed number of neurons, which means they do not regenerate.
Around 100 billion neurons in the brain and 1 billion neurons in the spinal cord
In all neurons, dendrite/receptor cell recieves signal and it then travels through the neuronto the pre- synaptic terminal.
All neurons have axons, myelin sheath, axon terminals, a nucleus and dendrites
Motor neurons relay impulses from the CNS to the muscles. this helps both organs including glands and muscles function
Motor neurons are multipolar, send and receive messages from many sources = much variation anatomically
Dendrite cell receives signal. Travels through neurone to the pre synaptic terminal
Sensory neurons tell rest of brain about the external and internal environment
They do this by processing info taken from 1 of 5 senses.
They relay impulses from these sense organs to the CNS
Sensory neurons only transmit messages so are unipolar
Relay Neurons/ Inter connector neurons
Relay neurons carry messages from one part of cns to another.
Relay neurons connect motor and sensory neurons.
Relay neurons send and receive messages from many sources so are multipolar.
Synaptic transmission= process by which nerve impulses are carried across small gap ( the synapse )between one neurone and another
Synapse= specialised gap between neurons through which the electrical impulse from the neurone is transmitted chemically.
Nerve impulse= an electrical signal which is carried by chemicals called neurotransmitters
Synaptic Transmission 2
Electricalnerve impulse travels down the neurone and prompts release of neurotransmitters at the pre-synaptic terminal
Neurotransmitters chemicals then released into synaptic fluid in synapse.
Adjacent neurone takes up neurotransmitters from the fluid and converts them into an electrical impulse
This impulse then travels down neurone to next pre-synaptic terminal.
Neurotransmitters= chemicals in the brain
Neurotransmitters like dopamine and seretonine.
It occurs at HIGH SPEED
Excitation and Inhibition
Not all messages prompt activation in same way.
This depends on 'action potential' of the post-synaptic neuron and the message type recieved.
Only certain neurotransmitters can unlock a message channel in certain receptors in post-synaptic neuron
When right neurotransmitter meets right receptor, specific ion channel in membrane is opened up.
Ions then flow through membrane into neuron along specific pathways.
Flooding of ions can cause a potential in dendrites
These potentials are excitatory or inhibitory
Exhitatory potentials- make it more likely for neurons to fire. If a synapse is more likely to cause post-synaptic neuron to fire it = excitatory synapse
Inhibitory potentials - make it less likley to fire. If message is likely to be stopped at post-synaptic neuron = inhibitory synapse