Phys Ch 8

is a complex network of nurons that form the rapid contol system of the body and carry electrical signals

composed of the brain and spinal cord

• Has Afferent sensory(to the brain) neurons that
• bring info to the CNS and efferent nurons (out of the brain) that carry information away from the CNS back to various parts of the body

control skeletal muscles

• control smooth cardiac muscles glands, and some adipose tissue.
• They are divided into sympathetic and parasympathetic branches

have a cell body and organelles with a nucleus

recevie incoming signals

Transmits electrical signals from the cell body to the axon terminal

neurotransmitters are released

The region where an axon terminal meets its target cell

the target cell (after the synapse)

the nueron that releases the chemical signal (before the synapse)

the region between the postsynaptic and the presynaptic cell

Material like proteins and oragnelles is transported between the cell body and axon terminal

provide phyiscal support and direct the gtowth of the neurons durring repir and development

in PNS form insulating myelin sheaths around neurons

found in CNS, Are modified immue cells that act as scavengers

Found in CNS, insulates the myelin shealths

Found in CNS, makes up the Blood Brain Barrier(BBB) with tight junctions

found in CNS, form of stem cells(new cells) and back up effectived damaged nerve cells

Are sections of uninsulated membrane occuring at intervals along the lenths of an axon

• Are depolarizations or hyperpolarization whos strength is directly proportional to the strenght of the triggering event
• Lose strenght as they move through cell

• Positive
• makes a neuron more likely to fire an action potential

Negative

make neurons less likely to fire an action potentioan (exceding)

• Are rapid electrical signals that travel undiminished in amplitude from cell body the axon terminals (no fading)
• All or none principle

• All stimuli great enough to bring the membrane to
• threshold will produce action potentials of identical magnitude

Of action potential is an increase of Na+ in the cell

Of action potential is due to K+ flow out of the cell (repolorzation)

Is when the cell has become more positive than the outside (action potential)

a brief period of time where a second action potential cannot be triggered no matter how large the stimulus

Higher than normal graded potential is required to trigger an action potential

occurs when sodium channels are opened and depolorizes a neuron making it easier to fire.

results in local hyperpolarizations (Slow down)

Movement of an action petential through the axon at high speed

Jumping of action potentials from node to node

Too much potassium in the blood

electrical signal passes directly from cytoplasm of one cell to another through gap junctions

Use neurotransmitters to carry info from one cell to the next diffusing across synaptic cleft.

Secrete acetycholine

secreate Norepinephrine, Glutamate GABA serotonin adenosine and nitric oxide

when a presynaptic neuron synapses on a larger number of postsynaptic neurons

When Several neurons provide input to a smaller number of postsynaptic neurons

Summation of simultaneous graded potentials from different neuron

repeated graded potentails reaching the trigger zone one after the other