NS functioning Flashcards
what do motor neurons do?
efferent neurons transmit neural messages about motor movement from the CNS to the PNS
what do sensory neurons do?
afferent neurons transmit neural messages about bodily sensations from the PNS to the CNS
what do interneurons do?
transfer neural messages between sensory neurons and motor neurons, the CNS is made up of interneurons
what is a neuron?
a nerve cell that receives and transmits neural messages
what is the somatic nervous system?
division of the peripheral ns that transmits neural messages related to voluntary motor movement (skeletal muscles)
what is the autonomic nervous system?
a division of the peripheral nervous system that regulates visceral muscles, organs, and glands, involved in unconscious responses
what are he branches of the autonomic ns?
sympathetic and parasympathetic
what does the parasympathetic ns do?
dominant during everyday life of an individual and calms the body, returning it to homeostasis
what does the sympathetic ns do?
becomes dominant when an individual is confronted with a threat/ stressor, energising the body (includes fight, flight, freeze)
what is the spinal reflex?
an unconscious response to sensory stimuli that is initiated by interneurons in the spinal cord independently of the brain
what is the process of the spinal reflex?
- sensory/ afferent neurons detect t stimuli
- interneuron/ relay neuron link motor and sensory neurone in spinal cord
- motor/efferent neurons enable response
- sensory message continues to travel to the brain & it independently registers the sensation
what is a conscious response?
a deliberate and voluntary action that is intentionally initiated by the brain and performed by the body (if the brain Is involved it is a conscious response)
what is an unconscious response?
an automatic and involuntary action that is performed by the body independently of the brain
what is the process of the brain in the CNS?
- Receives sensory information
- processes, integrates and organises it
- Initiates a bodily response to the skeletal muscles to respond to stimuli
what is the neural synapse?
the region that includes the axon terminals (presynaptic neuron), synaptic gap, and dendrites (postsynaptic neuron), where neurons meet
what is the neural pathway?
- axon terminals of the presynaptic neuron release neurochemicals into the neural synapse
- synaptic gap is the space between the presynaptic neuron and the postsynaptic neuron
- receptor sites on dendrites of the post synaptic neuron receive the neurochemicals
what is the process of the synaptic transmission?
- neurochemicals are produced in the axon terminals of the presynaptic neurons
- neurochemicals are released from the axon terminals of the presynaptic neuron into the synaptic gap
- neurochemicals bind to receptor on the dendrites of the postsynaptic neuron
- neurochemicals affect the postsynaptic neuron, either triggering or inhibiting a response
what are neurotransmitters?
chemical molecules that have an effect on one or two postsynaptic neurons and enable rapid communication between neurons
what are the two types of neurotransmitters?
glutamate (excitatory) and GABA (inhibitory)
what do excitatory neurotransmitters do?
have a stimulatory effect on the postsynaptic neuron, more likely to fire an action potential
what do inhibitory neurotransmitters do?
have a repressive effect on the postsynaptic neuron, less likely to fire and action potential
what are neuromodulators?
chemical molecules that have an effect on multiple postsynaptic neurons and produce relatively long-term effects as they modulate more slowly
What does glutamate do?
(excitatory) neurotransmitter, it has a role in learning and memory as they strengthen synaptic connections that are repeatedly activated during learning, it also has an important role in movement
what does GABA do?
(inhibitory) neurotransmitter, it regulates postsynaptic activation in neural pathways preventing the over excitation of neurons. it reduces anxiety by preventing excitatory neural signals. additionally it inhibits the uncontrolled firing of action potentials and therefore preventing seizures.
what are the types of neuromodulators?
dopamine (excitatory & inhibitory) and serotonin (inhibitory)
what does dopamine do?
when a person is rewarded for behaviour dopamine is produced in the VTA associated with the experience of pleasure. dopamine produced in the SN transmits neural information that enables smooth, coordinated, volunatary motor movement.
where is dopamine produced/ transmitted?
substantial nigra and the ventral tegmental area (both within the midbrain)
what does serotonin do?
(inhibitory) contribute to mood regulation and stabilisation. it regulates the 24 hr sleep/ wake cycle including quality and quantity of sleep. influences of feelings of alertness/ wakefulness in the day. depending on the receptor site: appetite, digestion, and arousal
where is serotonin transmitted/ produced?
raphe nuclei
what is the spinal cord?
a cable of nerve tissue that extends from the brain, connecting it to the peripheral nervous system
what are ascending tracts?
neural pathways that transmit sensory (afferent) messages from the peripheral NS to the brain
what are descending tracts?
neural pathways that transmit motor (efferent) messages from the brain to the peripheral NS
what are the stages of a spinal reflex?
- sensory/ afferent neurons detect stimuli
- interneurons or relay neurons link motor & sensory neurons in the spinal cord
- motor/efferent neurons enable the response
what is the role of neurons in the nervous system?
to receive, process and hen communicate neural information
what is synaptic plasticity?
the ability of synaptic connections to change over time in response to activity or experience (stimuli)
what is long term potentiation?
long lasting and experience dependent strengthening of synaptic connections that are regularly coactivated at high intensity simulation
what are some structural changes that occur during LTP?
- Increased number of receptor sites on dendrites on the postsynaptic neuron
- Bushier dendrites on the postsynaptic neuron due to sprouting
- Increased number of synaptic connections between neurons
why do structural changes occur during LTP?
occur to the neural synapse due to the increased release of neurotransmitters, specifically glutamate
what is long term depression?
long lasting and experience dependent weakening of synaptic connections between neurons that are not regularly coactivated
what are some structural changes that occur during LTD?
- decreased number of receptor sites on dendrites on the postsynaptic neuron
- decreased dendrites on the postsynaptic neuron due to pruning
- decreased number of synaptic connections between neurons due to pruning
what is sprouting?
the ability of dendrites or axons to develop new extensions of branches
what is pruning?
the elimination of synaptic connections that are not adequately activated
what is rerouting?
ability of a damaged neuron to create an alternative synaptic connection with an undamaged neuron
what are neurochemicals?
chemical substances that transmit neural information within the nervous system
what are memory traces?
Neural pathways formed during learning
what are the 3 ways that neuromodulators effect neurons?
-alter properties of multiple neurons
- change the responsiveness of receptor sites of a neurotransmitter
- change the neurotransmitter release patten of the presynaptic neuron
what are synaptic vesicles?
small sac-like structure found in the axon terminals oof the pre-synaptic neuron that stores and releases neurotransmitters
what is the function of synaptic vesicles?
Release their contents into the synaptic gap to allow communication to occur
