Neuroscience Exam 1

Front 1

How Electrical synapses are connected

Back 1

intracellular specialiaztion known as
gap junctions.

these form bridges

Front 2

Chemical synapses

Back 2

Mechanism: Action potentials cause calcium channels calcium ions stimulate vesicles causing neurotransmitters to be released

Size: 20 - 40 nm

Front 3

Electrical synapses

Back 3

connected through gap junctions

size: 3,5 nm

therefore: cleft has immediate regulation

Front 4

Benifit of electrical synapses over Chemical synapses

Back 4

They are faster due to direct connection

As postynaptic and presnaptic fire nearly at identical times, it can synchronize activity good when neurons need to fire at same time

also as intracellular signals such as ATP and second messengers cna pass through introcellular mechanisms are coordinated

Front 5

Structure of Gap Junctions

Back 5

six presynaptic connexons (hexameric complexes) and six postsynaptic connections connect to form a pore

Front 6

Characteristics of connexon pore

Back 6

larger than voltage-gated ion channels
i.e. less selctive
allows ATP and other metabolites to pass

can open and close in response to: voltage, pH, or other signals

Front 7

What composes connexons

Back 7

ion channel protein known as connexins

Front 8

Directionality of Electrical synapses

Back 8

can be bidirectional

however, can be normally directional
or reverse direction/ rectifying

Front 9

Chemical synapse mechanism

Back 9

1. action potential invades terminal of presynaptic neuron

2. change in membrane potentail activates voltage gated calcium channels to open

3. large amont of calicum outside cell to inside causes calcium to flood into cell

4. calcium influx causes synaptic vesicles to fuse to presynaptic membrane releasing neurotransmitter into synaptic cleft

5. neurotransmitters bind to post-synaptic receptors, increasing or decreasing ion flow

Front 10

What does neurotranssmiter induce current flow alter

Back 10

1. the conductance (ease at which particles can slow through a medium)

2. usually membrane potential

Futhermore what does this do

Hint 10

increase or decrease probability of action potnetial fireing

Front 11

How do neurotansmitters stop

Back 11

Ruptake
uptake to glial cells

enzymatic degredation

Front 12

acetylcholine on heart

Back 12

decrease heartrate

Front 13

Types of Ionic Receptors

Back 13

Ionotropic receptor

Metabotropic receptor

Note about neurotransmitters

Hint 13

Do not enter into postynaptic membrane

Front 14

Ionotropic receptor Characteristics

Back 14

Binds to ligantd gated ion channels

increase probability ion channel will open

Front 15

Metabotropic receptor characteristics

Back 15

g protein coupeld receptors

Front 16

types of neurotransmitters

Back 16

Small molecule neurotransmitters - mediate rapid synaptic responses

neuropeptide = mediate slower more ongoing responses

Front 17

End Plate

Back 17

where presynaptic spinal motor neurons synapse on postsynaptic muslcle cells

Front 18

EPP or End Plate Potential

Back 18

Change in membrane potential on postsynaptic muscle cell, if threshold is exceeded cause postynaptic action potential

Front 19

EPP and MEPP relatinoship

Back 19

minuature end plate potentials the excitatory post synaptic potentail produced from one vesicle release of neurotransmitter, EPP are caused by multiple MEPP's

Front 20

Tetradioxin

Back 20

poisin - blocks voltage gated sodium channels

Front 21

Curear

Back 21

blocks acetylcholine receptors

Front 22

What is the difference in release between neuropeptides and small neurostransmitters

Back 22

neuropeptides are thought to be spatially farther way and require higher frequency of calicum stimulation to cause its release.

i.e. neuropeptides take longer to release than small neurotransmitters

Front 23

synaptic vesicle reserve pool structure

Back 23

vesicles are held together by synapsin proteins which are bound to cytoskeleton actin

Front 24

Metabotropic receptors

Back 24

movement of ions through channel depends on multiple steps

Front 25

G potrein oupled receptor mechanism

Back 25

neurotransmitter binds to G-protein receptor

This activates G protein which detaches and either activates effector portein or ion channel