– small, ovoid cells with spiny processes Phagocytes that monitor the health of neurons

phagocytes that live in brain and spinal cord. Job is to eat up bacteria that can cause damage

– range in shape from squamous to columnar They line the central cavities of the brain and spinal column

- line the cavities of your spinal cord and brain. Brain has 4 cavaties full of cerebral spinal fluid.

• have cilia and move the cerebral fluid around the brain and spinal cord.

surround neuron cell bodies with ganglia

-  hover around nerve cell bodies

Armlike extensions from the soma Called tracts in the CNS and nerves in the PNS There are two types: axons and dendrites

outgoing info goes down the axon and out through the boutons

incoming messages comes in through the dendrites

axons and dendrites. Dendrites are shorter, diffusely branched, receptive (take in information to send in the body (the soma)) . the electrical signals on a dendrite are not action potentials;They are called graded potentials.

On the axons the electrical signals are always action potentials. Movement can be in two directions. Anterograde (toward the axon terminal) or retrograde (away from the axon terminal)

Anterograde — toward axonal terminal

Retrograde — away from axonal terminal

voltage measured between two points

the bigger the difference the bigger the potential.

the flow of electrical charge between two points

how many electrons flowing along the axon

hindrance to charge flow

what keeps the electrons from flowing.

Occurs when current passes through a myelinated axon only at the nodes of Ranvier.

- Neurotransmitter receptors mediate changes in membrane potential according to the amount of neurotransmitter released and the amount of time the neurotransmitter is bound to receptors.

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• dopamine, norepinephrine (NE), and epinephrine. Enzymes present in the cell determine length of biosynthetic pathway. Norepinephrine and dopamine are synthesized in axonal terminals. Epinephrine is released by the adrenal medulla.

• : neurotransmitters that open ion channels
  • Promote rapid responses
  • Examples: ACh and amino acids

• : neurotransmitters that act through second messengers
  • Promote long-lasting effects
  • Examples: biogenic amines, peptides, and dissolved gases

Growth is guided by scaffold laid down by older neurons, orienting glial fibers, release of nerve growth factor by astrocytes, neurotropins released by other neurons, repulsion guiding molecules, and attractants released by target cells.

are a brief reversal of membrane potential with total amplitude of 100 mV.

are only generated by muscle cells and neurons. They do not decrease in strength over distance. They are the principal means of neural communication.

in the axon of a neuron is a nerve impulse.

• - Substance P (mediator of pain signals), Beta endorphin, dynorphin, and enkephalins. Act as natural opiates; reduce pain perception. Bind to the same receptors as opiates and morphine. Gut-brain peptides – somatostatin, and cholecystokinin.

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  • Sensory input

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  • –  interpretation of sensory input. In the integration area the gray mater of the brain and spinal cord are where the cells are that make the decisions. And when they make a decision they send an input out to the muscles (the motor output)

                            Motor output –

Neuron

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: a body, axon and dendrites. Born w/ all the nerves you will ever have. Have a high metabolic rate (always doing something) so they have a bunch of mitchondrria. Function is to  send electrical signals, as well as signaling each other during development.

has unmyelinated axons. makes the decision. In comes the sense (ow hand on fire) out goes motor (pull hand outta fire) 1:51

Yes cause in white matter, white matter has myelin

do motor fibers have myelin on their axons?

Yes cause in the white matter. White matter has myelin

Have 2 things in  body

• ___________– keep electricity from flowing where you don’t want it. That’s why axons are covered with myelin.

 __________ substance with low electrical resistance Ion channels

• - Reflects the flow of ions rather than electrons. There is a potential on either side of membranes when:
•                The number of ions is different across the membrane
  • The membrane provides a resistance to ion flow