section 2 nervous system Flashcards
nervous system
brain, spinal cord, peripheral nerves
CNS
central nervous system; brain and spinal cord
PNS
Peripheral Nervous System, the sensory and motor neurons that connect the CNS to the rest of the body
brain lobes
frontal, temporal, parietal, occipital
cerebral cortex
outer region of the cerebrum, containing sheets of nerve cells; gray matter of the brain
spinal cord
Nerves that run up and down the length of the back and transmit most messages between the body and brain
Nerves
bundle of axons in PNS
Neuron
a specialized cell transmitting nerve impulses; a nerve cell.
sensory neurons
Detect sensory stimuli have sensory nerve endings rather than dendrites. Carry info about noxious stimuli
motor neurons
neurons that carry outgoing information from the brain and spinal cord to the muscles and glands therefore have dendrites
optic nerve
the nerve that carries neural impulses from the eye to the brain
extracellular fluid
fluid outside the cell
intracellular fluid
fluid within cells
potential difference (voltage)
the difference in electrical charge between two points in a circuit expressed in volts
membrane potential
the voltage difference across a membrane
inside the cell
More negative than the outside of the cell
1 second
1000 milliseconds
action potential
a neural impulse; a brief electrical charge that travels down an axon from axon hillock toward axon terminals
Depolarization
The process during the action potential when sodium is rushing into the cell causing the interior to become more positive.
concentration gradient
difference in the concentration of a substance from one location to another
Length of action potential
2ms
Size of action potential
Always the same size, change always from -70 mV to +30mV
firing frequency
Rate of producing of action potential per second s(-1)
Stability of action potential
Stable signals,
Can travel great distances without fading
Axon of some neurons very long. Toe to spinal cord
Synapse
the junction between the axon tip of the sending neuron and the dendrite or cell body of the receiving neuron
presynaptic neuron
neuron that sends the signal
postsynaptic neuron
the neuron on the receiving end of the synapse
Neurotransmitters
chemical messengers that cross the synaptic gaps between neurons
Glutamate
A major excitatory neurotransmitter; involved in memory
GABA
An inhibitory neurotransmitter in the brain. Gamma amino butyric acid
excitory postsynaptic potential
EPSP- graded depolariztion caused by the arrival of a neurotransmitter at the postsynaptic membrane.
inhibitory postsynaptic potential (IPSP)
an inhibitory hyperpolarization of the postsynaptic membrane of a synapse caused by the liberation of a neurotransmitter by the terminal button
What happens to neurotransmitter
Diffuse away from synapse
Broken down by enzymes
Taken back up into the axon terminal from which it was realised
temporal summation
Summation by a postsynaptic cell of input (EPSPs or IPSPs) from a single source over time.
spatial summation
Integration by a postsynaptic neuron of inputs (EPSPs and IPSPs) from multiple sources.
Polarised
difference in electrical charge across the membrane
