2 the nervous system Flashcards
Central nervous system
- comprised of the brain and spinal cord
- receives sensory information from the peripheral nervous system
- sends motor information to the peripheral nervous system
Brain
receive info from the outside world via the senses and coordinate appropriate responses
Spinal cord
- sends sensory/afferent messages towards the brain
- sends motor/efferent messages away from the brain
Peripheral nervous system
- comprised of the muscles, organs,
and gland - sends sensory info to the central nervous system
- receives motor info from the central nervous system
Somatic nervous system
A network of neurons within the body that transmit information from receptor sites to the CNS, and then carry information to the muscles to initiate voluntary movement
Autonomic nervous system
A network of neurons that carry information between the CNS, and the organs and glands, to ensure they are regulated without conscious awareness
Sympathetic nervous system
A branch of the autonomic nervous system that prepares the body for vigorous activity.
The Neurotransmitterfight-flight-freeze response
An adaptive response initiated by the sympathetic nervous system and prepares the body to confront a stressful situation to optimise the chance of survival.
Parasympathetic nervous system
A branch of the autonomic nervous system that maintains homeostasis and calms the body down after vigorous activity.
Sensory neuron
Transmits sensory information from your body to your brain.
Motor neuron
Transmits motor information from your brain to your body.
Interneuron
Transmits information between sensory and motor neurons.
Typical neural communication
- Sensory neurons at the receptor site (skin) feel the sensation.
- They pass it along afferent tracts through the PNS, to the spinal cord in the CNS, and eventually to the brain.
- Interneurons in the brain then communicate with motor neurons.
- Motor neurons send a signal via efferent pathways through the spinal cord in the CNS, then through the PNS, and effectually to an effector site (muscle)
Spinal reflex
An automatic response that is initiated by neurons in the spinal cord, independent of the brain.
Structure of neurons
Dendrite: Receives incoming neural messages
Soma: Contains the nucleus with the genetic material for the neuron
Axon: Pathway down which the neural message travels
Myelin sheath: Fatty tissue that encases the axon to aid in speed of transmission
Axon terminals: Exit pathways for neural messages to make their way to the next neuron
Terminal buttons: Releases a neurotransmitter to a receiving neuron for communication purposes
Neurotransmission
- A neural impulse (electrical energy) runs from the dendrite down the axon to the axon terminals.
- The terminal buttons release a NT (chemical energy).
- This NT crosses the synapse
(space from one neuron to the next). - The NT is picked up by the receiving neuron via the dendrites.
Neurotransmitter
The chemical substance released by the terminal button of a neuron, necessary for neural communication.
Excitatory
Increasing the likelihood that the
neuron will fire an action potential.
Inhibitory
Decreasing the likelihood that the
neuron will fire an action potential.
Glutamate - Memory
An excitatory neurotransmitter that
is involved in memory and learning
GABA - Calming
An inhibitory neurotransmitter associated with calming feelings of anxiety, stress, or fear.
Neuromodulator
A neuromodulator is a chemical messenger that enhances signal transmission.
Dopamine - Pleasure
A neuromodulator that is involved in drive, motivation and motor movement.
Serotonin - Mood
A neuromodulator that is involved in mood stabilisation.
Neuroplasticity
The ability of the brain to physically change in response to experience
- developmental
- adaptive
Synaptic plasticity
The ability of synaptic connections to change over time in response to activity or experience.
Long-term potentiation (LTP)
The long-lasting and experience-dependent strengthening of
synaptic connections that are regularly activated.
Long-term depression (LTD)
The long-lasting and experience-dependent weakening of synaptic connections between neurons that are not regularly activated.
Neural processes
Synaptic plasticity is possible as a result of sprouting, rerouting, and pruning.
Sprouting
The ability of dendrites or axons to change over time in response to activity or experience.
Rerouting
The ability of a neuron that is connected to a damaged neuron to create an alternate synaptic connection
Pruning
The elimination of synaptic connections that are not adequately activated.
