transmit information from the organs and tissues to the Central Nervous System
transmit info from the CNS to the effector cells
receive and pick up messages from other cells
the cell's life support center
a long tubular structure that passes messages away from the cell body to other neurons, muscles, or glands
is an electrical signal that travels down the axon
terminal branches of axon
form junctions with other cells
covers the axon of some neurons and helps speed neural impulses
types of neurons
GABA (gamma-aminobutyric acid)
enables muscle action, learning, and memroy
influences movement, learning, attention, and emotion
affects mood, hunger, sleep, and arousal
helps control alertness and arousal
GABA (gamma-aninobutyric acid)
a manor inhibitory neurotransmitter
major excitatory neuron-transmitter; involved in memory
autonomic nervous system
§the part of the peripheral nervous
system that controls the glands and the muscles of the internal organs (such as
sympathetic nervous system
division of the autonomic nervous system
that arouses the body, mobilizing its energy in stressful situations
parasympathetic nervous system
division of the autonomic nervous system that clams the body, coserving its energy
a simple, automatic, inborn response to a sensory stimulus
naturally or experimentally caused
what are the 3 main functions of the nervous system?
* receiving input from the senses
*processing information by relating it to the previous experiences
* producing and monitorying bodily actions or output
what are the two main cell types in the nervous system??
neurons - specialized to respond rapidly to signals and send signals of their own
glial cells- physically hold neurons within the nervous system
- help guide growth of neurons
-aborb chemicals to maintain stable chemical environment
the gates are closed and positive ions are on the outside with the negative ions on the inside of the cell
-a neural impulse, a brief electrical charge that travels down the axon
-generalted by the movement of the positively charged atoms in and out of channels in the axon's membrane
-this process is due to stimulation from either heat, chemicals, pressure, or light.
the time it takes for the positive ions to be pumped out
-the level of stimulation required to trigger a neural impulse
-neurons either fire or don't fire: this is called the all or nothing principle
Is the axon membrane selectively permeable?
Yes, it has gates which keep electrically charged particles (ions) to enter or keep out
What does the sodium pump do?
picks up any positive ions from the inside and puts them back outside
what is action potential?
when stimulus is large enough to excite a neuron (breaks threshold)- it stops the sodium pump and opens the axon membrane gates which causes the iside and outside of the axon to reverse its charge- it depolarizes the neurons.
what are receptors?
receptors receive the neurontransmitters released by the end bulbs
what is a refractory period?
a brief time after an action potential during which a neuron cannot fire another action potential.
It repolarizes the neuron by the ions moving back to their original spots
what are interneurons?
neurons that have no axons or very short axons. they integrate information with a structure rather than sending information between structures.
types of glia cells
support cells outside of the brain and spinal cord
largest glia and are named astrocytes because they tend to be star shaped
they fill the space between neurons, resulting in close contact between the two
involved in brain-blood barrier
regulate how far neurostransmitters, released by the terminal button, can spread
regulate chemical levels in the extracellular space
they wrap their processes around most axons in the brain and spinal cord
smallest of the glia cells
remove debris from the nervous system
what's the electrical charge state of a resting neuron?
Central Nervous System
part of your nervous system that is encased by bone - includes the brain and spinal cord
Peripheral nervous system
exists outside of protection from bone
has TWO MAJOR DIVISIONS
- autonomic nervous system: primarily responsible for regulating internal states
-----has sympathetic nerves and parasympathetic nerves
- somatic nervous system : primarily responsible for interacting with the external environment
the spinal cord is gray on the inside and white on the outside
has 31 segments and each of these segments has a pair of spinal nerves attached to it
what are the 5 groups of segments for the spinal cord?