unit 3 Flashcards
what are the two parts of the nervous system
the central nervous system and the peripheral nervous system
some examples of functions of the nervous system
- analysing sensory information
- storing information
- making decisions
what is the CNS made up of
the brain and spinal cord
what is the PNS made up of
the somatic nervous system and the autonomic nervous system
what does the somatic nervous system contain (voluntary)
sensory and motor neurons
what do sensory and motor neurons do
- sensory neurons take impulses from sense organs to the CNS
- motor neurons take impulses from the CNS to the muscles and glands
what does the autonomic nervous system consist of (involuntary)
the sympathetic and parasympathetic systems
what does the sympathetic system do
speeds up heart rate and breathing rate while slowing down peristalsis and production of intestinal secretions
-the parasympathetic system changes these in the opposite way
what happens in a converging neural pathway
impulses from several neurons travel to one neuron
-this increases sensitivity to excitatory or inhibitory signals
what happens in a diverging neural pathway
impulses from one neuron travel to several neurons so affecting more than one destination at the same time
what happens in a reverberating pathway
neurons later in the pathway link with earlier neurons, sending the impulse back through the pathway
-this allows repeated stimulation of the pathway
what is the cerebral cortex
the cerebral cortex is the centre of conscious thought
-it also recalls memories and alters behaviour in the light of an experience
what does cerebral cortex contain
there is localisation of brain functions in the cerebral cortex, it contains sensory areas, motor areas and association areas
-there are association areas involved in language processing, personality, imagination and intelligence
where is the information from the right visual field and controls of the right side of the body dealt with
the left hemisphere
where is information from the left visual field and controls of the left side of the body dealt with
the right hemisphere
where does the transfer of information between the cerebral hemispheres occur
the corpus callosum
what three things does memory involve and what three things does it include
encoding, storage and retrieval of information
and
past experience, knowledge and thoughts
where does information entering the brain pass though and enter
passes through the sensory memory and enters the STM
how is information transferred from the STM to the LTM
rehearsal, organisation and elaboration
what does the sensory memory retain
all the visual and auditory input received for a few seconds
does the STM have a big capacity
no, it has a limited capcity
how many pieces of information can the STM hold
7 items
what is the serial position effect
Items at the start of a long list are remembered through rehearsal and those at the end are remembered because they are still in the STM, and the ones in the middle are lost
how can the capacity of the STM be improved by
chunking
what happened to information if they aren’t transferred to the LTM
it is lost by displacement or decay
what is displacement
when information is pushed out of the STM by new information
does the LTM have a limited capacity
no it had an unlimited capacity and can hold information for a long time
what is ROE
R- rehearsal (shallow form of encoding information into the LTM)
O- organisation (when information is organised into logical categories)
E- elaboration (deeper form of encoding which leads to improved information retention)
what is retrieval aided by
use of contextual cues
what are contextual cues
relating information to the time and place it was initially encoded into the LTM
what is the structure of neurons
dendrites - cell body- axons
what do dendrites do
receive nerve impulses and carry them towards the cell body
what do axons do
carries nerve impulses away from the cell hodu
what does the cell body contain
a nucleus and cytoplasm, the cytoplasm contains organelles such as mitochondria to provide energy for impulses and ribosomes which synthesises proteins for the synthesis of neurotransmitters
what are the axons surrounded by
the myelin sheath
what is the myelin sheath
a layer of fatty material that insulates the axon and increases the speed of nerve impulse conduction
what is myelination
the extent to which an axon is covered in myelin (this continues from birth to adolescence)
what diseases can damage the myelin sheath
multiple sclerosis (MS) which results in a loss of muscular co-ordination
what do glial cells do
- support neurons
- produce the myelin shesth
what are the types of neurons
- sensory neuron
- inter neuron
- motor neuron
what is the space between the ends of neurons knows as
a synapse
how are impulses related across synaptic clefts
by chemicals called neurotransmitters
2 examples of neurotransmitters and how and why are they are removed
-acetylcholine (enzyme degradation)
-noradrenaline (re-uptake)
they are removed to prevent continuous stimulation of postsynaptic neurons
what is the neuron before the synaptic cleft known as
the pre-synaptic neuron
what is the neuron after the synaptic cleft known as
post-synaptic neuron
where are neurotransmitters stored
in vesicles in the axon endings of the presynaptic neuron
action of neurotransmitters
- A nerve impulse passes through a neuron and reaches the end of the presynaptic neuron
- Neurotransmitters are released from vesicles into the cleft on arrival of the impulse
- Neurotransmitters diffuse across the synaptic cleft
- Neurotransmitter binds to receptors on the membrane of the postsynaptic neuron
what do receptors found on the postsynaptic neuron determine
whether the signal is excitatory (causes an increase in action) or inhibitory (causes a decrease in action)
what is the sufficient number of neurotransmitter molecules known as
the threshold
what are weak stimuli known as
sub-threshold stimuli and are too weak to cause the transmission of a nerve impulse
what can synapses do with weak stimuli
filter them out
what is summation
a series of weak stimuli which trigger an impulse
what are endorphins
endorphins are neurotransmitters which act like natural painkillers by stimulating neurons which are involved in reducing the intensity of pain