- Cells in the Nervous System- Neurons- 100-150 billion - In CNS they don’t regenerate ★ Glia○ Supporting cells○ Form a barrier b/w the blood and brain ○ Do regenerate ■ Astrocytes● Forms a barrier b/w the blood & brain ■ Oligodendroglia ● Myelin- insulates axons and moves impulses along axons more quickly○ Microglia○ Scavenger cells-Inputs and cell body= cell body & dendrites (is there something important going in the neuron) Sends an electrical signal along its channel (axon is the conduction zone), sends the info to the axon for it to interpret it for other parts of the body ● Get excited ● Or inhibits ➢ Two Types of Info Processing ○ Electrical signaling ○ Graded potentials ■ Excitation ■ Inhibition ■ Action potentials- big spikes of electrical activity goes down the axon into the axon terminals ● Chemical signal- ● Synapses ● Neurotransmitters● Agonists - things that act like neurotransmitters, gets them going (caffeine) ● Antagonists- or inhibits it and doesn’t make it work as well 1. Lipid bilayer in the little video, salt= NA+ CL- (ions), stick a channel in the membrane- may only allow one type of ion into the membrane, get a lot of excess positive charge anda lot of negative charge on the outside of the membrane, so the charges go against each others and start pushing each out in the opposite direction (charge gradient)- will soon be equal to each other in terms of level of charge. Reaches an equilibrium. Sodiums stop moving inside but outside have more charge than outside and shows equilibrium potentialonly permeable to sodium (made the inside negative with PT) ● Immigration problem- and people coming in and out is about the same ➢ Action Potentials ➢ Membrane, little sodium inside, a lot outside, a lot of potassium inside, and only alittle on the outside, ○ Channel is opened by the ligand, and binds to it (drugs etc), then opens ○ Can let a little sodium in starting at -70 milable (since it’s negative lets a little leak of potassium come in)- resting potential ○ Graded potential: small, if nothing happens will die, axons start at the voltage gated channel, sodium- open fast potassium channels- slow ○ Opens up the gate creating that action potential/ excitation (open NA channel, comes rushing in)- membrane potential goes way up to _30 to 50 ○ Then potassium comes rushing out sending it back down to about -80 mlb.■ Sodium potassium pump, to recharge ❏ Signaling- Electrical Potentials ❏ Resting Potential- 10-50 mV❏ Graded potentials ❏ Excitatory Postsynaptic Potential (EPSP) (usually occur after a syapse)❏ Inhibitory Postsynaptic Potential ❏ Action potential- activated of the voltage gated channels open ❏ Sodium/ potassium pumps (always active)