PSY 250 Lecture Notes - Lecture 4: Acetylcholine, Reuptake, Choline
Garrett: Brain & Behavior, 3e
11
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7+$/0#8(9-%8/.&(#.:(;&6(7&',4*(
! !
1) The!cells!that!make!us!who!we!are!
a. 2&-'+.4!are!specialized!cells!that!convey!information!in!chemical!and!electrical!forms,!transmit!
commands!to!other!areas,!and!generate!thought,!emotion,!and!memory!!
i. Basic!Structure!
1. <&.:'/%&4!receive!information!from!the!outside!world!or!from!other!cells!
2. The!4+,#,!or!cell!body,!contains!the!organelles,!including!the!nucleus,!and!carries!out!
basic!cell!activities!
3. =>+.4!carry!information!to!other!neurons!(or!muscles!or!organs)!
a. A!sheath!of!,6&8/.!surrounds!the!axon!
b. Branches!at!the!end!of!the!axon!terminate!in!swellings!called!%&',/.#84!
c. 2&-'+%'#.4,/%%&'4!are!released!from!terminals!
4. The!connection!between!two!neurons!is!called!a!46.#$4&!
ii. Types!of!Neurons!
1. 5&.4+'6(.&-'+.4!bring!information!about!the!body!and!the!environment!into!the!
central!nervous!system!
2. ?.%&'.&-'+.4!connect!neurons!over!short!distances!
3. @+%+'(.&-'+.4!carry!commands!to!the!muscles!and!organs(!
iii. The!Neural!Membrane!is!made!of!fat!and!protein,!holds!a!cell!together,!and!regulates!what!
enters!and!exits!the!cell!
1. The!A&4%/.B(C+%&.%/#8!refers!to!the!difference!in!electrical!charge!between!the!inside!
and!outside!of!an!inactive!neuron’s!membrane!!
a. Usually!around!–70!mV!
b. Sodium!/+.4!are!concentrated!outside!the!neuronal!membrane;!potassium!ions!are!
concentrated!inside!
c. The!4+:/-,D$+%#44/-,($-,$!maintains!the!ion!differences!by!expelling!3!sodium!
ions!for!every!2!potassium!ions!it!brings!in!
i. The!E+'0&(+E(:/EE-4/+.!is!a!force!that!moves!ions!from!the!side!of!the!membrane!
where!they!are!most!abundant!to!the!side!where!they!are!least!abundant!
ii. The!&8&0%'+4%#%/0($'&44-'&!is!a!force!which!repels!ions!from!the!side!of!the!
membrane!with!the!same!charge!and!attracts!them!to!the!side!with!the!
opposite!charge!!
iii. The!movement!of!ions!across!the!membrane!is!further!regulated!by!the!opening!
and!closing!of!protein!channels!in!the!membrane.!
2. The!=0%/+.(C+%&.%/#8!is!a!brief!depolarization!of!the!neural!membrane!that!enables!the!
neuron!to!communicate!over!long!distances!
a. The!membrane!is!depolarized!by!a!local!potential!that!is!(typically)!about!10!mV!
more!positive!than!the!resting!potential!(or,!above!threshold!level).!
b. The!membrane!rapidly!depolarizes!to!approximately!+30!or!+40!mV!when!sodium!
channels!open!and!sodium!ions!rush!into!the!cell,!making!the!electrical!charge!inside!
the!cell!more!positive!
c. The!sodium!channels!then!close,!and!potassium!channels!open.!The!positive!charge!
of!the!cell!moves!the!potassium!out.!As!potassium!leaves,!the!cell!briefly!becomes!
slightly!more!polarized!(P80!mV)!than!normal.!
