biopsychology Flashcards
what is the nervous system divided into?
central nervous system and peripheral nervous system
what is the job of the central nervous system?
- involves the brain and spinal cord and cerebral cortex
- is in charge of reflex actions
what is the job of the central nervous system?
- involves the brain and spinal cord and cerebral cortex
- is in charge of reflex actions
- centre of conscious awareness
what is the peripheral nervous system divided into?
somantic nervous system and autonomic nervous system
what is the role of the somantic nervous system (voluntary)
- responsible for carrying sensori and motor information within spinal cord through nerves
- 31 pairs of spinal nerves
- 12 pairs of cranial nerves from brain
what is the role of the autonomous nervous system (involuntary) ?
- governs vital functions in the body e.g breathing, heart rate, digestion
what is the autonomous nervous system divided into?
sympathetic nervous system and the parasympathetic nervous system
what is the role of the sympathetic nervous system (action and stress) ?
- preparation for fight or flight
- weak reaction
- uses as much energy as possible
what is the role of the parasympathetic nervous system (calm and relaxation) ?
- maintains and conserves body energy functions
- strong reaction
what are some sympathetic behaviours?
- dilating pupils
- accelerates heartbeat
- inhibits digestion
- relaxes bladder
what are some parasympathetic behaviours?
- constricts pupils
-stimulates salivation - slows heartbeat
- contracts bladder
what is the role of the sensory neurons?
- carries impulses from the PNS, receptors e.g pain receptors in the skin to the CNS. They have long dendrites and short axons. The cell body is in the middle of the axon
what is the role of the relay neuron?
carries impulses from sensory neurons to motor neurons. They have short dendrites and short axons.
they make up 97% of all neurons
what is the role of the motor neurons?
carries impulses from CNS to the effector e.g muscles or glands.
They have short dendrites and long axons
what is the structure of a neuron?
- they vary in size from less than a mm up to a m
- the cell body (soma) includes a nucleus which holds all the genetic information for the body
- the dendrites carry nerve impulses away from neighboring neurons towards the cell body
- the axon carries impulses away from the cell body down the length of the neuron
- the axon is covered in a mylin sheath that protects the axon and speeds up chemical messages
- the myelin sheath is in gaps called “nodes of ranvier”
- t the end of the axon is the terminal buttons
what is electrical transmission?
when a neuron is activated by a stimulus, the inside of the cell becomes positively charged for a split second, causing an action potential. This created an electrical impulse that travels down the axon towards the end of the neuron
what is chemical transmission?
- neurons connect with each other through neural networks
- each neuron is separated from the next by a gap called the synapse
- signals within neurons are transmitted electrically
- however, signals between neurons are transmitted chemically across the synapse
-when electric impulses reach the presynaptic terminal, it triggers the release of neurotransmitters from the synaptic vessels
what are neurotransmitters?
- they are chemicals that diffuse across the synapse to the next neurone
- they are taken up by the dendrites of the post synapitc neuron
- they are then put back into electrical impulses
- direction of travel is only one way
- neurotransmitters have been identified in the brain, spinal cord and some glands
what is excitation?
when a neurotransmitter such as adrenaline, increases the positive charge of the postsynaptic neuron. This increases the likelihood that the postsynaptic neuron will pass on the electrical impulse
what is inhibition?
what a neurotransmitter, such as serotonin, increases the negative charge of the postsynaptic neuron. This decreases the likelihood that the postsynaptic neuron will pass on the electrical impulse
what is the effect of the hypothalamus?
stimulates and controls the release of hormones from the pituarity gland
what hormone is released from the pituitary gland and what is the effect?
growth hormones are released and it controls the release of all the other hormones as well as producing growth hormones
what hormone is released from the pineal gland and what is the effect?
melatonin is released and it releases higher levels when its dark and decreases production when it’s lighter
what hormone is released from the thyroid gland and what is the effect?
thyroxine is released and it controls metabolism
what 2 hormones are released from the adrenal gland and what is the effect?
- adrenal cortex produces cortisol - increases in response to stress to regulate blood pressure, poor immune function
- adrenaline - releases in emergency situations
what 2 hormones are released from the ovaries and what is the effect?
oestrogen and progesterone are released and secrete hormones that mature the body for puberty e.g menstruation
what hormone is released from the testes and what is the effect?
testosterone secretes hormones that mature the body for puberty e.g characteristics like a deepened voice
what is the somatosensory cortex?
located in the parietal lobe: responds to heat, cold, touch, pair and our sense of body movement
what is the motor cortex?
in the frontal lobe: responsible for controlling voluntary movements. both hemispheres have one - controlling muscles- damage can result in impaired movement
what is the occipital lobe?
primary function is vision
what is the temporal lobe?
auditory ability and memory
what is broca’s area?
on the frontal lobe of the left hemisphere and is responsible for thought into speech
what is Wernicke’s area?
located on temporal lobe and understanding and producing speech
what is Localisation of Function?
the theory that different areas of the brain are responsible for specific behaviours, processes, or activities - follows the idea that if a certain part of the brain is affected - only the function of that one area will be affected
what is the structure of the hemispheres of the brain?
-Divided into 2 symmetrical halves (left and right hemisphere)
-Some physical and psychological functions are dominated by one in particular (lateralisation)
-Activity on left side of body is controlled by right hemisphere and vice versa
strength of localisation - links to mental disorders
- Darin Dougherty et al (2002) reported on 44 people with OCD who had undergone a cingulotomy
- a post-surgery follow up after 32 weeks showed that 30% of the participants had success and 14% had a partial response
strength of localisation - brain scans
- steven peterson et al (1988) used brain scans to look at activity in the Wernicke’s area during listening tasks and Broca’s area during reading tasks
- this provides evidence for localisation
weakness of localisation - Language Localisation Questioned
- Language may not be localised to just Broca and Wernicke’s areas
-Advances in brain imaging techniques, like fMRI, mean neural processes in the brain can be studied with more clarity than before
-It seems language function is distributed more holistically - so-called language streams have been identified across the cortex
-Rather than being confined to a few key areas, language may be organised more holistically in the brain, contradicting localisation theory
strength of localisation - phineas cage
-Most of his left frontal lobe damaged in accident but he survived the damage but he turned from someone who was calm to quick-tempered and rude
-Suggested the frontal lobe may be responsible for regulating mood
-Unique cases of neurological damage like this tend to support localisation theory but it is difficult to make meaningful generalisations from the findings of a single individual and conclusions depend on the subjective interpretation of the researcher
what is lateralisation?
the two hemispheres work separately and have their own separate functions
how is lateralisation different to localisation?
- localization is how much any one function is located in a specific area of the brain
-lateralisation is how much anyone function is located more in one hemisphere than the other
what are some examples of lateralisation?
- brain damaged individuals
- non brain damaged individuals
- methods such as the WADA test
what is the corpus callosum?
a bundle of nerves that allows the hemispheres to send information to the other
what is the split-brain research for lateralisation?
A series of studies which began in the 1960s (and are still ongoing) involving epileptic patients who had experienced a surgical separation of the hemispheres of the brain to reduce severity of their epilepsy. This allowed researchers to investigate the extent to which brain function is lateralised
what is a Commissurotomy ?
Severing of the corpus callosum that links the two hemispheres
Evaluation of research using split brain patients
-Its highly controlled lab research so lacks ecological validity
-Limited sample size
-Participants had epilepsy (lack of generalisability)
Left Hemisphere Functions
- Language, speech and comprehension
- Recognition of words, letters and numbers
- Analysis and calculations
- Time and sequencing
Left Hemisphere Functions
- Language, speech and comprehension
- Recognition of words, letters and numbers
- Analysis and calculations
- Time and sequencing
Right Hemisphere Functions
- Recognition of faces, places and objects
- Context / perception
- Spatial ability
- Creativity
Sperry and Gazzaniga (1967)
-11 patients whose corpus callosum had been severed
-They were presented with images to either the left or right visual field
-A range of tasks were used and patients had to respond with either their left (right hemisphere) or right hand (left hemisphere)
-Found the patient could say what they saw in their right visual field, because this hemisphere is responsible for language but not in their left visual field, because this hemisphere cannot process language
-Patient could draw this image with their left hand - did not require language
Strength of lateralisation:
Multitasking
-Increases neural processing capacity (ability to multitask)
-Rogers et al (2004) found in a domestic chicken, brain lateralisation is associated with an enhanced ability to perform 2 tasks simultaneously (finding food and being vigilant for predators)
-Using one hemisphere to complete tasks leaves the other hemisphere free to engage in other functions
-Provides evidence for the advantages of brain lateralisation and demonstrates how it can enhance brain activity in cognitive tasks