Download “Definitions” section of your binder Central nervous system

Central nervous system: the brain and spinal chord
Spinal cord: nerves that run up and down the length of
the back and transmit most messages between the body
and the brain
Peripheral nervous system: nerves branching beyond the
spinal cord into the body
Neurons: the long, thin cells of nerve tissue along which
messages travel to and from the brain
Synapse: the gap that exists between individual nerve
cells
Neurotransmitters: the chemicals released by neurons
which determine the rate at which other neurons fire.
Somatic Nervous System (SNS): the part of the
peripheral nervous system that controls voluntary
movement of skeletal muscles
Autonomic nervous system (ANS): the part of the
peripheral nervous system that controls internal
biological functions
-The nervous system is broken into 2 parts…
->the central nervous system (CNS)
->the peripheral nervous system (PNS)
*transmit information from the organs to
the CNS and vice versa
-All nerves are protected
->brain by the skull and sheathing
->spinal cord by vertebrae
-> PNS by sheathing
-Messages from and to the brain travel in nerves (long
strings of neurons)
->this is via electrical signals emitted as a signal
once the neuron is stimulated past the minimum,
or threshold level.
-part of a Neuron
->Dendritess: thin fibres protruding from the cell
body
->The cell body
-> Axon
->Axon terminals
-the axon carries impulses from the cell body toward
axon terminals which release neurotransmitters to
stimulate the dendrites of the next neuron
Video of neurons firing
http://youtu.be/T6NhLfZuYIg
Video of neurotransmitter close-up
http://youtu.be/90cj4NX87Yk
http://youtu.be/cNaFnRKwpFk
-The synapse: the junction or connection between two
neurons.
->this is jumped by neurotransmitters
* neurotransmitters excite the receptors in
the next neuron
-several types of neurotransmitters
-> too much or too little neurotransmitters can
cause emotional and physical disfunction
-Different types of neurons
->Afferent neurons (sensory neurons) relay
messages from our senses
->Efferent neurons (motor neurons) send signals
from brain to muscles and glands
->Interneurons process signals between neurons
-SNS controls voluntary activity
->muscles etc.
-ANS controls involuntary activity
->organs, heartbeat, etc.