Unit Three NeuroBiology Flashcards
describe the structural division of the nervous system
CNS- brain + spinal cord
PNS- somatic nervous system. autonomic nervous system.
describe the function of the somatic nervous system
controls mainly voluntary conscious actions
contains sensory + motor neurons
what is a sensory neuron
they take impulses from the sense organs to the CNS
what is motor neurons
take impulses from the cns to muscles and glands
describe the function of the autonomic nervous system
consists of sympathetic and parasympathetic systems
controls involuntary unconscious actions
describe the function of the sympathetic nervous system
(fight or flight)
increases heart rate
increases breathing rate
slows down peristalsis
slows down production of intestinal system
describe the function of the parasympathetic nervous system
( rest and digest)
decreases heart rate
decreases breathing rate
increases peristalsis
increases production of intestinal system
describe antagonistic
they have opposite effects
converging pathways
in converging neural pathway, impulses from several neurons travel to one single neuron.
this increases sensitivity to excitatory or inhibitory signals
eg. night vision
diverging pathways
in a diverging neural pathways impulses from one single neuron travels to several neurons so affecting more than one destination at the same time
increases coordination and fine motor control
eg. surgery
reverberating pathways
neurons later in the pathway links back with earlier neurons , sending the impulse back through the pathway this allows repeated stimulation of the pathway
eg. breathing
describe the cerebral cortex
center of conscious thought
recalls memories and alters behaviour due to experiences
brain functions in the cerebral cortex are localised
describe the structure and function of the corpus callosum
a band of fibres that connects both hemispheres of the brain and allows for information to be exchanged
describe the left cortex/cerebral hemisphere
controls the right visual field and controls the right side of the body
has speech area
describe the right side of the cortex/ cerebral hemisphere
controls the left visual field and controls the left side of the body
what is the function of the occipital lobe
sight
what is the advantage of a cortex which is extensively convoluted
to maximise surface area on the brain to make space for cells to connect
what areas is the cortex divided into
sensory, association, motor
what is the role of sensory areas
to receive nerve impulses from sense organs
process sensory organs
what is the role of association areas
processing language, personality, imagination and intelligence
what is the role of motor areas
send nerve impulses to he muscles+ glands
generate movement signals
define memory
memory is the storage, retention and retrieval of information including past experiences knowledge and thoughts
define short term memory
all information entering the brain passes through sensory memory and eters short term memory
describe sensory memory
sensory memory retains all the visual and auditory input recieved only for a few seconds. only selsected images and sounds are then encoded into short term memory
define long term memory
information is then either transferred to long term memory or discarded
what is the capacity of most people’s short term memory and how long does it typically last
7-9 pieces of information for 20-30 seconds at a time
How does chunking help with short term memory
Grouping to make single items together to improve capacity
How does rehearsal help with memory
A shallow form of encoding information into long term memory
What is the serial position effect
The tendency of a person to recall items that come first and last best and forget the intermediate items
What is working memory
Short term memory being able to process data, to a limited extent as well as store it
Can preform simple cognitive tasks
How are memories lost from stm
By displacement(replaced by new items entering)
Or decay (degradation)
Describe Organisation in memory
Involves placing the information into related groups/categories
Elaboration meaning
Involves adding extra information to add meaning
Elaboration is regarded as deeper form of encoding
This leads to improved information retention
Contextual cues
Relating to the time and place when information was initially encoded into long term memory
How does the brain go about retreiving information
Aided by the use of contextual cues
Describe the function of a nerve cell(neuron)
Neuron’s are adapted to carry electrical impulses
Describe the function of a glial cell
Produce the myelin sheath and support neurons
Describe the cell body
Structure- contains a nucleus and cytoplasm
Function - controls all cell activity
Describe axons
Structure- single nerve fibre
function- transmits electrical signals down the length of the neuron
What is the function of interneurons
To send signals
Describe the function of myelin
Surrounded by a myelin sheath
This insulates the axon and increases the speed of impulse conductions
How does. Myelination effects development
Responses to stimuli tin the first two years of life are not as rapid or coordinated as those of an older child or adult
Describe multiple sclerosis
Destroys the myelin sheath using a gradual loss of coordination
What is the function of a synapse
Connects neurons together
What is the function of neurotransmitters
Converts electrical signal to a chemical a signal to diffuse through the gap
How are neurotransmitters stored
In vesicles in the axon endings of the presynaptic neurons
What happens to the neurotransmitters when the nerve impulse reaches the presynaptic terminal of a nerve fibre
When an electrical impulse arrives at the axon ending the neurotransmitters are released into the cleft
How does the post synaptic membrane respond to the neurotransmitters
Diffuse across the cleft and bind to the receptors on the membrane of the postsynaptic neuron
This triggers an electrical impulse in the postsynaptic neuron
How is removal of neurotransmitters achieved
Acetylcholine is an enzyme that breaks down neurotransmitters
how is the neurotransmitters remove from the synaptic cleft
A hormone noradernaline takes the neurotransmitter back u by the presynaptic membrane
Explain how a weak excitatory signal does not cause the neuron to fire
A minimum number of neurotransmitter molecules must attach to receptors on the post synaptic membrane in order to reach the threshold required to transmit the impulse
How do endorphins trigger the experience of pleasure or satisfaction
Increased levels of endorphins also stimulate the feelings of pleasure obtained from activities such as eating, sex and prolonged excersise
What conditions trigger endorphins release
(Feis)
Severe injury
Prolonged exercise
Stress
Certain foods
What is an agonist
Drugs which mimic the shape of a neurotransmitter
What is effected when drugs are taken
mood, cognition,preception, behaviour
What is a presynaptic neuron
Neuron carrying signal before synapse
What is a post synaptic neuron
Neuron that carries signal after synapse
Neurotransmitter meaning
Protein that crossed the synapse and bind to receptor on postsynaptic membrane
Receptors description
Can be inhibitory or excitatory bind to neurotransmitter
What is a Threshold
The number of neurotransmitters required to generate a signal
Summation
Several weaker signals combining to reach threshold
Describe antagonists
A drug that binds to a receptor but causes no action. Blocking any neurotransmitters
Reuptake inhibitors
Allows the effects of some neurotransmitters to last longer as they prevent reabsorption of the neurotransmitter
Describe inhibitors of neurotransmitters
Inhibit enzymes that break down neurotransmitters in the synaptic cleft
Describe excitatory and inhibitory receptors
Excitatory- increases contraction of muscle fibres
Inhibitory- decreases contraction of muscle fibres
