process info and form action potentials

enables us to experience life

damage can be devastating

everything we feel, touch, smell :)

carry info to NS

liiiiike if you touch your phone

carry info from NS to effectors

liiiike if you move your arm

communicate between afferent and efferent

ie. touch a hot stove

hand jerks away

support neurons physiologically

immunologically

anddd metabolically

brain and spinal cord

most NS cells are found here

neurons that extend/reside outside of the brain and spinal cord

basically everything else

junctions between neurons and their target cells

how neurons interact with other cells

ie. arm movement requires NS and muscular cells

cell body

dendrites

axon

axon terminals

neurotransmitters

chemical signals at synapse

facilitators - make sure stuff doesn't get lost

more abundant in the brain than neurons!

-release neurotransmitters

-keep neurons aligned during development

-nourish neurons

-insulate axons

-protect neurons from particles

-maintain extracellular environment

-provide immune functions

glia in the CNS and PNS that provide insulating membrane

-myelin!

covering that increases the rapidity of signal  transmission and gives NS white, shiny appearance

neurological disease

myelin becomes inflamed and breaks down

nerve detioration

contribute to blood-brain barrier by surrounding the tiniest vessels in the brain

alcohol and anesthetics break blood-brain barrier (fat soluble)

act as macrophages and mediators of inflammatory responses in immune function

killlll invadersssss rawwwwr

Membrane Potential

K is more prevalent inside the cell

Na is more prevalent outside of the cell

K leaks out = negative charge on inside

"Yeah, K, come on in / Na, you suck and you're not allowed in."

huge shift in membrane potential

caused by sudden ion channel openings and rapid closings

NERVE IMPULSE

electric potential difference

forced that causes charged particles to move between two points (pressure & water)

*key players: Na, K, Ca, and Cl^-

actively expels Na from inside the cell

exchanges it for K outside of the cell

3:2 ratio

requires energy

kinda like proton pump

Potassium Leak Channels

K naturally leaks out

Na has to be pumped out

controlled by voltage

chemical gradient

mechanical means

self explanatory - gates open and close

sudden, transient, large changes in membrane potential

2m/sec unmyelinated; 100m/sec myelinated

from -60mV --> +50 mV

Action Potentials

Process

1. resting potential

2. depolarization due to Na ion channels opening

3. positive reinforcement

4. more to open in axon hillock

5. meets threshold

6. even more open

7. positive potential = action potential

8. Na voltage gates close

9. K voltage gates open

10. Na gates have refractory period

11. resting potential is reestablished

all-or-none, self-regenerating event

larger diameter axons = less resistance

myelinated areas can be "jumped"

(vertebrates) = much faster

ie. moving walkways at airports

neurotransmitters from presynaptic cell induce a change in the postsynaptic cell

more common

prime examples of chemical synapses

acetylcholine as a neurotransmitter

created in axon terminal

sometimes in cell body --> packaged by Golgi apparatus and transported

Motor End Plate

modified part of the muscle cell plasma membrane

(receiver)

depends on the receptor that it binds to

like hormones!

Popular Neurotransmitters

(6)

acetylcholine

serotonin

endorphins

nitrous oxide

dopamine

norepinephrine

example of long-term potentiation

linked to glutamate induced increased sensitivity due to activation of two different receptors after high frequency stimulation 

slows diffusion of serotonin

Enzymatic Destruction

Diffusion