Voluntary Movement

Neurotransmitters, How is the Nervous System Communicating?

Outline:

Membrane Potentials

Neurotransmitters

  • inhibitory

  • exhibitory

Membrane Potentials

  • Important insights into nature of electrical signals used by nerve cells were obtained roughly 80 years ago

  • electrodes were placed on the surface of an optic nerve of an invertebrate eye.

  • Cell membrane potential results from the separation of net positive and negative charges within the cell

  • Action potential s are the basic events the nerve cells use to transmit information from one place to another

  • Action potentials great importance of the brain function.

  • The resting membrane potentials is around ~-60 mV but can rang from -80 mV to -40 mV depending on the type of the nerve cell.

    • the absence of any stimulation , the resting potential is constant generally

  • hyperpolarization-(turning something off) are more negative than before

  • Depolarization( turning on)- getting more positive neurons.

    • once depolarization hits a certain threshold, and AP is generated

Amino Acid Neurotransmitters

  • Provide the majority of the excitatory and inhibitors in the NS system

  • Excitatory transmission is mediated largely by the acidic amino acid glutamate

  • While inhibitory neurotransmission is primarily glycine in the spinal cord

  • GABA in the brain

/

Excitatory Synaptic Connections are typically found on the major dendrite neurons

  • type one

  • will release glutamate

Inhibitory Synaptic connections are typically found on the cell body

  • type 2

  • will release glycine or GABA depending on the need

Glutamate (turn on)

  • opens channels and cause the cell to depolarize

  • opens for sodium, potassium, and calcium

  • opens for positive charged ions

  • the cell will become depolarized

GABA (turning them off)

  • increases the amount of chloride (negative) that flows to neuron

  • hyperpolarize the neuron

  • found in the brain, unlike glycine in the spinal cord

*amount of GABA can cause a deficiency of the amount in the brain

  • this causes hyper excitable in the brain, electrical storm in the brain resulting in seizures.

  • alcohol can increase GABA activity and dec. in glutamate activity. When you black out, the glutamate is elevated instead.