nervous system functioning Flashcards
unit 3 aos 1
what does the central nervous system consist of?
brain and spinal cord
role of the brain
centre of almost everything we think, feel and do
role of spinal cord
send sensory information to the brain, receive motor information from the brain and send it to relevant parts of the body, initiate reflexes
what does the peripheral nervous system consist of?
all the nerves outside the central nervous system
role of the peripheral nervous system
send sensory information to CNS from muscles, organs, and glands
sends motor information from CNS to muscles, organs, and glands.
role of somatic nervous system
carries sensory info to CNS and motor info from CNS
responsible for voluntary movement of skeletal muscles
role of autonomic nervous system
connects CNS to body’s internal organs
responsible for involuntary movement of body’s visceral muscles
is not completely self-regulating.
role of sympathetic nervous system
increases activity of most visceral muscles, organs, and glands
prepares body for fight or flight.
role of parasympathetic nervous system
decreases the activity of most visceral muscles, organs, and glands
maintains a normal state of bodily functioning
role of enteric nervous system
embedded within the walls of the gastrointestinal tract and is dedicated to its functioning
what is conscious response?
a reaction to a sensory stimulus that involves awareness, usually voluntary, goal-directed, and have some control over
process of conscious response
- sensory info of detected by sense organs
- sensory info that is detected is carried by sensory neurons
- brain processes this information
- once info is processed, the brain sends motor info, carried by motor neurons
- this enables conscious movement, carried out by skeletal muscles
what is unconscious response?
a reaction to a sensory stimulus that does not involve awareness, cannot ordinarily control its occurrence
made by autonomic nervous system or spinal cord
what is a spinal reflex?
an unconscious, automatic response controlled solely by neural circuits in the spinal cord
process of withdrawal reflex (spinal reflex)
- sensory receptors detect incoming sensory info.
- info is carried by sensory neurons and received by interneurons in the spinal cord.
- interneurons relay sensory info to motor neurons, activating relevant skeletal muscles to enable movement.
sensory (afferent) neuron
carries sensory information from PNS to CNS
motor (efferent) neuron
carries motor information from CNS to PNS
interneuron
connects sensory and motor neurons, only found in CNS
electrochemical process in neurons
-electric: electric impulse generated inside a neuron (action potential)
-chemical: electrical impulse triggers release of chemical messengers from a neuron, received by another neuron
dendrites
-thin extensions form from the cell body of a neuron
-role is to receive info from other neurons
axon terminals (terminal buttons)
-small knoblike swelling, located at the end of the axon collaterals
-role is to release neurotransmitters.
synapse
-the sit of communication between adjacent neurons
-describes the synaptic gap, the presynaptic neuron, and the postsynaptic neuron
synaptic gap
the tiny space between the axon terminal of a presynaptic neuron and the dendrite of a postsynaptic neuron
presynaptic neuron
the neuron that releases the neurotransmitters
postsynaptic neuron
receives neurotransmitters
neurotransmitters
chemical messages produced by neurons
process of neural transmission
- neurotransmitters are released at the axon terminal of presynaptic neuron
- neurotransmitters travel across the synaptic gap
- neurotransmitters bind themselves to the receptor sites of postsynaptic neurons (dendrites)
- neurotransmitters that bind at the postsynaptic neuron have either an excitatory or inhibitory effect
excitatory neurotransmitters
-makes the postsynaptic neuron more likely to fire (info is more likely to passed onto another neuron)
-activity being stimulated
inhibitory neurotransmitters
-makes the postsynaptic neuron less likely to fire (info is less likely to passed onto another neuron)
-activity being supressed.
glutamate
main excitatory neurotransmitters in CNS
GABA
main inhibitory neurotransmitter in CNS
neuromodulator
chemical molecule which affects multiple postsynaptic neurons
what makes neuromodulators different from neurotransmitters?
-affects multiple postsynaptic neurons at the same time
-modulates neural activity (enhances inhibitory or excitatory effects of neurotransmitters)
-slower to take effect but has longer-lasting effects
dopamine
responsible for:
-voluntary motor movement
-pleasure
-reward-based learning
-motivation
-addictive behaviours
-can be excitatory or inhibitory
serotonin
responsible for:
-mood regulation
-sleep-wake cycle regulation
-only has inhibitory effects
synaptic plasticity
the ability of the synapse to change due to experience
sprouting
the ability of the dendrites to form new branches
rerouting
the ability of neurons connected to damaged ones to create alternative connections
pruning
the elimination of synaptic connections
long term potentiation
the long-lasting enhancement of synaptic transmission due to repeated stimulation
(makes postsynaptic neurons most likely to fire, increasing efficiency)
long term depression
the long- lasting decrease in the strength of synaptic transmission and neuronal response
what are five similarities of LTP and LTD?
-both involve glutamate and occur at glutamate synapses
-both have long lasting effects
-both involve changes in excitability
-both are activity dependent
-both are forms of neural plasticity
