Biopsychology

what is the nervous system

controls the body through neurones and tissues through sensory information which controls behaviour such as thinking and moving

what is the peripheral nervous system

• all the nerves outside the CNS

• function is to relay nerve impulses from the CNS to the rest of the body and vice versa

what is the autonomic nervous system

• involuntary actions that take place in the body such as digestion

• system is necessary as vital bodily functions would not be as efficient if they were voluntary

• sympathetic and parasympathetic nervous systems

what is the parasympathetic nervous system

• reverses the impact of the sympathetic nervous system after the emergency

• e.g. slowing heart rate down and reducing blood pressure

what is the sympathetic nervous system

• involuntary responses to help us deal with emergencies→ fight or flight response

• e.g. increasing heart rate and adrenaline

• slows bodily processes that are less important in emergencies- e.g. digestion

what is the central nervous system

• controls behaviour and regulates the bodies physiological processes

• brain receives information and sends it to the muscles and glands through nerves and the spinal cord

• brain and spinal cord

what is the spinal cord

• relays information between the brain and the rest of the body

• allows the brain to monitor and regulate bodily functions

• connected to the rest of the body through spinal nerves which connect muscles and glands

• enable simple reflex without brain involvement- fast response

what is the function of the brain

• divided into the cerebrum, cerebellum, diencephalon and brain stem

• all parts of the brain have different functions for the body such as speech and visual processing

describe the cerebrum

• largest part of the brain

• divided into 4 different lobes

• split in halves called cerebral hemispheres

• each half has specialised behaviours, though they communicate with each other

what does the frontal lobe do

thought and production of speech

what does the occipital lobe do

• processes visual images

what does the cerebellum do

• responsible for fine motor neurone skills and balance

• coordinates muscles to allow precise movements

• abnormalities here create speech and motor problems

describe the diencephalon

• includes the thalamus and hypothalamus

describe the thalamus

• relay station for nerve impulses coming from the senses and directing them to the right part of the brain to be processed

describe the hypothalamus

• regulates body temperature, hunger and thirst

• links the endocrine system and the nervous system

• controls the release of hormones

describe the brain stem

• regulates automatic functions essential for life

• e.g. breathing, heartbeat and swallowing

• motor and sensory neurones travel through here allowing impulses to pass between the brain and spinal cord

what do motor neurones do

form synapses with muscles and control their contractions

describe neurotransmitters

chemical substances that play an important role in the working of the nervous system by transmitting nerve impulses across the synapse

describe relay neurones

• most common type of neurone in the CNS

• allow sensory and motor neurones to communicate with each other

describe sensory neurones

carry nerve impulses from sensory receptors to the spinal cord and brain

what is a synapse

the conjunction of the end of the axon of one neurone and the dendrite or cell body of another

what is synaptic transmission

• refers to the process by which a nerve impulse passes across the synaptic gap from one neurone to another

• presynaptic neurone→ post synaptic neurone

what is a dendrite

branches that receive messages from other neurones

what are nodes of ranvier

gaps in the myelin sheath that speed up nerve impulses

describe the myelin sheath

fatty insulation around the axon that helps signals travel faster

what are schwann cells

cells that make the myelin sheath in the peripheral nerves

describe axons

long fibres that carries electrical impulses away from the cell body

describe terminal boutons

endings of the axon that release neurotransmitters to the next cell

describe the order of how neurones work

stimulus (sense organ)→ receptor→ sensory neuron→ relay neuron→ motor neuron→ effector→ response

what is the endocrine system

• Network of glands throughout the body that manufactures and secretes chemical messengers (hormones) into the blood stream

• Works with the nervous system to regulate physiological processes

• Uses blood vessels rather than nerves to deliver hormones to target areas of the body

• what functions in the body do hormones control

• metabolism

• puberty and reproduction

• responses to stress

• responses to environmental factors such as heat, cold and pain

where is the hypothalamus

in the brain

what is the function of the hypothalamus

• keeps the body in a state of homeostasis

• releases hormones to the pituitary gland which then controls other glands

• maintains daily cycles, e.g. sleep and breathing

• acts as a sensor

where is the pituitary gland

the brain

what is the function of the pituitary gland

• stimulates other glands to release their own hormones

• regulates testosterone, sperm, oestrogen production

where is the pineal gland

the brain

what is the function of the pineal gland

• regulates the body’s circadian rhythm

• secretes melatonin

• stops the secretion of melatonin during the day when it is light outside

where is the thyroid gland

the throat

what is the function of the thyroid gland

• controls the body’s metabolism

• releases thyroxine

• converts the nutrients you eat into fuel for energy

where is the thymus

chest

what is the function of the thymus

• protects the body from pathogenic threats such as viruses and bacteria

• produces thymosin

• stimulates production of white blood cells

where is the pancreas

belly button area

what is the function of the pancreas

• role in digestion

• produces enzymes to break down food we eat

• produces insulin and glucagon to regulate blood glucose levels

what happens in the body after eating

• blood sugar increase

• insulin released into bloodstream

• uptake of glucose from the bloodstream- stored as glycogen

• blood sugar levels decrease

what happens to the body after skipping a meal or strenuous activity

• blood sugar decreases

• glycogen releases glucose into blood stream

• blood glucose increases back to a normal

where is the adrenal gland located

above the kidneys

what is the function of the adrenal gland

• releases adrenaline

• help regulates essential functions such as metabolism, blood pressure and immune response

• fight or flight response

what is the function of the testes

• releases testosterone

• development of male sex organs

• voice lowering

• growth of facial and body hair

what is the function of the ovaries

• releases oestrogen and progesterone

• widening of hips and the development of breasts

• starts the menstrual cycle

• growth of body hair

what is an excitatory effect

• switches on and excites the nervous system

• increases the likelihood of a neuron firing

• increases the likelihood of a new action potential forming in the postsynaptic cell

• e.g. adrenaline and dopamine

describe the inhibitory effect

• switches off the nervous system

• e.g. serotonin and gaba

• decreases the likelihood of a neuron firing

• calms the mind and body

what is summation

• when a neuron adds up all the signals it receives to decide whether to fire

• acts like a voting system- if there is enough signals, it is exhibitory and the neuron will fire, if there is more no signals, there will be an inhibitory response and the neuron wont fire

what is temporal summation

• the same neuron sends signals quickly one after another

• so the strength builds up

• neurotransmitter doesnt have time to fade away so the effect builds up

what is spatial summation

• two different neurons sending the same signal at the same time-

• combined effect from all signals

describe the threshold in summation

• for an action potential to occur and be passed on, a transmitted neuron needs to exceed a threshold

• - more signals for one thing than another

what is acute stress

short term- e.g. being chased by a bear

what is chronic stress

long term

what is the fight or flight response

• reacting to a situation of danger where the body prepares to defend itself

why does the fight or flight response exist

• survival- primes the mind and body for extreme action

• not designed for modern world stress

describe the sympathetic physiological changes during acute stress

• heart rate increases

• blood goes to muscles

• pupils dilate

• release of glucose

describe the parasympathetic physiological changes during acute stress

• heart rate decreases

• blood goes back to the digestive system and less essential functions

• pupils constrict

describe the HPA axis

• sequence of bodily activity in response to stress

• involves the hypothalamus, pituitary gland and adrenal cortex

what occurs in the HPA axis

hypothalamus releases CRH→ goes to the pituitary gland and causes the release of ATCH→ goes to adrenal cortex and cortisol is released

when does the HPA axis occur

in chronic stress

what is the function of ATCH

stimulates the adrenal cortex to release stress related hormones→ e.g. cortisol

what is the function of cortisol

• quick bursts of energy and a lower sensitivity to pain

• impaired cognitive performance and a lower immune response

what is the function of the amygdala

• associates sensory signals with emotions associated with fight or flight→ e.g. fear or anger

• sends the distress signal to the hypothalamus

describe feedback

brings the body back to homeostasis using the parasympathetic nervous system

describe CRH

• causes the pituitary gland to release ACTH

• released into the blood stream as a response to the stressor

what is the function of the adrenal cortex

• releases hormones such as cortisol

• hormones released help the body to cope and sustain stress after the initial surge

what is the function of the adrenal medulla

• releases adrenaline into the blood stream during the fight or flight response

• e.g. increases HR, increases BP, sends blood to the muscles and raises blood sugar

evaluate the fight or flight response using gender bias

• tendency in research to only study men- ignores important factors such as genes that help curate the response during dangerous situations- such as the SRY gene only being present in the male y chromosome

• hard to study and draw accurate conclusions- form of beta bias

evaluate the fight or flight response with the idea that men and women respond differently to stress

• taylor et al 2000

• women have a tendency to tend and befriend → protect themselves and their offspring and forming protective alliances

• suggests that fight or flight isn’t a universal response→ shows that there are gender differences which must be considered

evaluate the fight or flight response using freeze

• freezing is also considered a stress response

• e.g. deer in headlights

• animals might freeze whilst evaluating what they should do next to best protect themselves

• shows fight or flight isnt a universal response

evaluate the fight or flight response using the modern world

• current stressors (e.g. exams and financial problems) dont require the same level of energetic response

• this can lead to physical damage to blood vessels and heart disease showing it cause more damage than good

• shows that there is a genome lag and the environment as a society has changed faster than our biological makeup

what are EEGs used to study

• sleep

• emotional reactions/lack of

• epilepsy

what are ERPs used to study

• cognitive tasks

• decision making

what are FMRIs used to study

• brain injury

• cognitive tasks

• dementia

• schizophrenia

what are post mortems used to study

• brain injury

• dementia

• schizophrenia

what is the procedure that William scoville performed

• a bilateral medial temporal lobe resection

• removed the hippocampus and surrounding structures

describe the amnesia types found by scoville

severe anterograde amnesia

• inability to create new memories

limited retrograde amnesia

• losing memory prior to surgery

what were the key findings from scoville

• relationship between the hippocampus and memory retention

• procedural memory remained intact

• episodic and semantic memories were heavily impacted

what is procedural memory

motor skills

what was scovilles analysis

• brain was preserved and sliced

• confirmed that the role of the hippocampus in consolidating declarative memory and providing 3D mapping of the damaged structures

• medial temporal lobes are crucial for memory formation- and helps distinguish between implicit and explicit memory systems

what are the strengths of post mortem

• physical evidence- not just a theory

• able to view the whole brain including deeper structures→ which EEG cannot view

what are the limitations of post mortem

• brain cells are dead so it cannot show brain activity→ no temporal validity

• cannot compare to what the brain looked like before

• lack of causation

• cannot generalise conclusions to all brains

what are the variables impacting causation in post mortems

• length of time the post mortem was done after death

• other brain illnesses

what are the ethical issues of post mortems

may not be possible to get fully informed consent

what do FMRIs measure

• increased blood flow to certain parts of the brain when it is being used

• areas of the brain light up on the screen when more o2 is being used

• blood oxygen levels detected

what does BOLD stand for in FMRIs

blood oxygenated level dependant

what is the process of an FMRI

• participant alternates between a period of doing tasks and a control state (e.g. eyes closed)

• FMRI data then used to identify the brain areas where there is a matching pattern of change

• data can be used to conclude areas that are activated by the stimulus

what are the strengths of FMRIs

• non-invasive

• doesn’t expose the brain to any harmful radiation

• objective and reliable way of investigating psychological phenomena

• good credibility

what are the limitations of FMRIs

• no a direct measure of neutral activity

• only measures activity in one area so cannot tell us how the different regions communicate with one another

• only takes images every 2 seconds- not very frequent

what do ERPs measure

• small voltage changes in the brain triggered by events or stimuli

• may require many presentations of the stimulus and then responses are averaged together

what is a cognitive ERP

• ERP's generated after the first 100 milliseconds reflect the manner in which the subject evaluates the stimulus

• demonstrates information processing 

what are sensory ERPs

 

• Waves occurring within the first 100 milliseconds after presentation

• reflects initial response to the physical characteristics of the stimulus 

what are the strengths of ERPs

• continuous measure of processing in response to a stimulus

• more precise way of investigating the brain compared to an EEG

• can measure the processing of stimuli even without a behavioural response

• can covertly measure the processing of a stimulus

what are the limitations of ERPs

• so small and difficult to detect from other electrical activity in the brain

• requires a large number of trials to gain meaningful data

• only sufficiently strong voltage changes are detected

• electrical activities deep in the brain are not recorded

what is the process of an EEG

• electrodes placed on the scalp detect small electrical charges from activity in the brain cells

• when the signals from electrodes are graphed over a period of time, the representation is an EEG

what are the 4 basic wave patterns of an EEG

• alpha waves

• beta waves

• delta waves

• theta waves