central nervous system (CNS) Flashcards
what is the central nervous system made up of
brain and spinal cord. surrounded and protected by cerebral spinal fluid which supplies nutrients and cushions the CNS from movement of the skull and spinal column
what is a neuron (purpose of and describe)
transmits info
network of neurons and the connections between them make up the central nervous system. they do not touch each other so there is a synapse between them. then transmit nerve impulses along the length of an individual neuron and across the synapse
what is the synapse
the junction between the axon of one neuron and dendrite of another. known as the synaptic gap
what are neurotransmitters
chemical released when one neutron crosses the synaptic gap and is received by special receptor sites on the next neuron
what are receptors
receptors are a certain shape prepared to receive a neuron transmitter from another neuron. if the neurotransmitter fits it is passed on. if it doesn’t the message is blocked
what are hormones
chemicals released into the blood stream. produced by glands in the endocrine system. affect physiological and behavioural functions. hormones that affect behaviour act upon specific receptor sites in the brain. involved slow and longer acting responses
what are genes
contained on chromosomes found within the nuclei of cells
made up of DNA
carry information from one generation to the next
influences development by triggering the productions of enzymes and proteins that are involved in the production of specific cells
what is the sympathetic nervous system
responsible for preparing body for fight or flight
what is the automatic nervous system
controls the body involuntary movements and controls the organs of the body
what is the peripheral nervous system
all of the nervous system outside the CNS
what is the somatic nervous system
controls voluntary movement and transmits signals to and from sense and muscles
what is the parasympathetic nervous system
responsible for restoring the body to resting levels
what are dendrites
finger like structures surrounding a cell body
what is an axon
long extension from the cell body of a neuron
what is an axon hillock
specialised part of the cell body of a neuron connecting to the axon
what is the myelin sheath
cell that surround and protect axons forming an insulation layer
what are the nodes of ranvier
areas around an axon where the myelin sheath thins
what are the synaptic buds
small structures at the end of an axon that contains neurotransmitters that carry the neurones that carry the neurones messaged into the synapse
what is GABA
inhibitor of messages and calming
what is norepinephrine
gives attentions and prepares for fight or flight
what is acetylcholine
memory and learning
what is dopamine
pleasure feelings and addiction
what is glutamate
cognitive functioning and dangerous if too much
what is serotonin
happiness and good mood - low levels gives depression§
what is reuptake
neurontransmitter is absorbed back into the presynaptic neuron
what is the excitatory postsynaptic potential
makes the neurones more likely to fire an action potential
what is action potential
electrical impulse in a neuron
how do neurones work
1) nerve impulses travel down an axon
2) nerve impulses reaches synaptic terminal
3) this triggers the release of neurotransmitters
4) the neurotransmitters are fired into the synaptic gap
5) if successfully transmitted the neurotransmitter is taken up by the post synaptic neuron
6) neurotransmitters binds with receptors on the dendrite of the adjacent neuron
7) the message will continue to be passed in this way via electrical impulses
what is the effect of caffeine
suppresses the actions of adenosine, so increases neural activity so temporary increases in mental alertness and thought processing and reduces drowsiness and fatigue. does not directly increase energy metabolism and will in long term suppress it. reduces blood flow to brain and can lead to headaches
what is the effect of nicotine
binds to and activates receptors called the cholinergic receptors. normally activated when they bind to acetylcholine (maintain healthy respiration, heart function and muscle movement). nicotine has a similar structure to acetylcholine, it disrupts normal functioning.
pain, anxiety and other negative symptoms are relieved and positive sensations are increased
what is the effect of amphetamines
stimulants. increase the activity of dopamine and norepinephrine. cause the release of dopamine and blocks reuptake. inhibits the storage of dopamine in vesicles and inhibits the destruction of dopamine by enzymes. short term effects are an increased heart rate and reduced appetite, long term effects are weight loss an tremors.
what are the strengths of this synaptic transmission explanation
method has scientific credibility, brain scanning is a strong method as it can be reliable if more than one person checks the data
evidence from people showing certain behaviour who have low levels of certain neurotransmitters in the brain. supports the idea that synaptic transmission is how messages pass in the brain
patients with parkinsons disease are offered a drug called L-dopa they can experience hallucinations (symptom of schizophrenia - high levels of dopamine, synaptic transmission can help to explain various disorders)
weaknesses of the synaptic transmission explanation
cannot generalise animals to humans as there are differences
argument relating to cause and effect - do genes cause the abnormal levels of neurotransmitters or does it begin when neurochemical activity changes
quite simplistic - Allen and Stevens fond that less than half the neurotransmitters in transmission arrived from the presynaptic neurones being picked up by the post synaptic neurones - more complex
