Ch 48 Flashcards
Nervous processes info. in 3 stages
-sensory input, integration, motor output
sensory neurons
-recieve signals from sensors that detect external stimuli and internal condition
interneurons
-on CNS
-intergrate info sent to brain/ganglia
motor neurons
-send motor output out of brain or ganglia
-trigger muscle or gland activity
central nervous system
-brain and nerve cord
-intergration takes place
peripheral nervous system
-carries info into and out of CNS
-neurons of PNS form nerves
cell body
where most of neurons organelles are
dendrites
-highly branchd extensions on neuron that receives signals from other neurons
axon
-longerextension that transmits signals to other cells at synapses
axon hillock
-cone shaped base of axon
synaptic terminal/bulb
-bulb at end of axon terminal where neurotransmitter molecules are stored/released
-electrical signal (action potential) > chemcial signal (neurotransmitter)
neurotransmitter
-chemical messengers
-signaling molecule secreted by neuron to affect another cell across a synapse
-over 100
-5 groups:
-acetylcholine
-Biogenic amines (norepinephrine, dopamine, serotonin),
-Amino acids (GABA, glutamate, glycine),
-Neuropeptides (substance p)
-Gases (nitric oxide)
-a single one may have more than a dozen diff. receptors
synapse
junction between axon and another cell
-info. is transmitted from presynaptic (neuron) to postsynaptic cell (neuron, muscle, or gland cell)
-most are chemical synapses
-many neurons have this on dendrites and cell body
membrane potential
-voltage
-difference in electrical charge across plasma membrane
-major source is resulting buildup of negative charge within neruon
-becomes more negative: at resting potential, hyperpolarized
-becomes more positive; at resting potential, depolarized
resting potential
-membrane potential of neuron not sending signals
-neuron contains many open K+ channels and fewer open Na+ channels
-K+ diffuses out of cell