Ch 2: Nervous System Functioning

afferent

conducting or conducted inwards or towards something

autonomic nervous system

a subdivision of the peripheral nervous system that connects the central nervous system to the body's internal organs and glands, providing feedback to the brain about their activities

brain

an intricate network of cells that plays a vital role in processing information received through nerve pathways from the body and in directing actions within the body

central nervous system

the brain and spinal cord

conscious response

a reaction to a sensory stimulus that involves awareness; usually voluntary, goal-directed and with some degree of control over it; compare with unconscious response

dopamine

a neurotransmitter or neuromodulator with multiple functions depending on where it acts; functions include roles in coordinating movement, learning and behaviours that are rewarding

enteric nervous system

a sub-division of the autonomic nervous system embedded within the walls of the gastrointestinal tract and dedicated to its functioning

efferent

conducted or conducting outwards or away from something

excitatory effect

when a neurotransmitter stimulates or activates a postsynaptic neuron to perform its functions; compare with inhibitory effect

ganglia

small clusters of neurons

gamma-amino butyric acid (GABA)

the primary inhibitory neurotransmitter in the central nervous system, making postsynaptic neurons less likely to fire

glutamate

the main excitatory neurotransmitter in the CNS, thereby enhancing information transmission by making postsynaptic neurons more likely to fire

inhibitory effect

when a neurotransmitter blocks or prevents a postsynaptic neuron from firing and therefore performing its functions; compare with excitatory effect

interneuron

a neuron which transmits impulses between other neurons, especially as part of a reflex arc

long-term depression

the long-lasting decrease in the strength of synaptic connections and transmission and neuronal response; compare with long-term potentiation

long-term potentiation

gradual strengthening of the connections among neurons from repetitive stimulation

motor neuron

a nerve cell forming part of a pathway along which impulses pass from the brain or spinal cord to a muscle or gland

nervous system

complex, highly organised network of specialised cells that enables the brain to receive information about what is going on from both inside and outside the body and to respond appropriately

neural pathway

a route based on interconnected neurons that form a communication network within the brain and between the brain and other parts of the nervous system and body

neural synapse

the site where communication typically occurs between adjacent neurons; also called neural junction or synapse

neuromodulator

a neurotransmitter that can influence the effects of other neurotransmitters; also called modulator neurotransmitter

neuron

the building blocks of the brain and the rest of the nervous system

neurotransmission

the transmission of nerve impulses between neurons or between a neuron and a muscle fibre or other structure

neurotransmitter

a chemical substance produced by a neuron that carries a message to other neurons or cells in muscles, glands or other tissue; compare with neurohormone

parasympathetic nervous system

a sub-division of the autonomic nervous system that calms or restores the body to its normal state of functioning after the need for sympathetic nervous system activation has passed; compare with sympathetic nervous system

peripheral nervous system

entire network of nerves located outside the central nervous system; carries information to and from the central nervous system (via its somatic and autonomic sub-divisions)

pruning

the elimination of weak, ineffective or unused synapses and hence synaptic connections

rerouting

when new connections are made between neurons to create alternate neural pathways

sensory stimuli

any event or object that is received by the senses and elicits a response from a person

sensory neuron

nerve cells that are activated by sensory input from the environment

sensory receptor

a nerve ending that sends signals to the. central nervous system when it is stimulated

serotonin

a neurotransmitter or neuromodulator with multiple functions depending on where it acts; functions include emotional processing, mood, and sleep onset

somatic nervous system

a sub-division of the peripheral nervous system that carries sensory information to the central nervous system and motor information from it

spinal reflex

an unconscious, involuntary response to certain stimuli, initiated within the spinal cord and controlled solely by neural circuits; also called reflex arc

spinal cord

a long, thin bundle of nerve tissue connecting the brain and rest of the body via the peripheral nervous system; initiates simple reflex responses independently of the brain; see also spinal reflex

sprouting

the creation of new extensions on a neuron to allow it to make new connections with other neurons

synaptic plasticity

the ability of a synapse to change in response to experience

synaptic gap

the tiny space between the axon terminal of a presynaptic neuron and the dendrite of a postsynaptic neuron; also called synaptic cleft

sympathetic nervous system

a subdivision of the autonomic nervous system; activates internal muscles, organs and glands to prepare for vigorous activity or to deal with a stressor, fear stimulus, threat or emergency; compare with parasympathetic nervous system

unconscious response

a reaction to a sensory stimulus that does not involve awareness, meaning it is involuntary, unintentional, automatic and we cannot ordinarily control its occurrence.