Powerpoints 4 & 5

Question 1

What are the classes of proteins found at post-synaptic sites?

Answer 1

Scaffolding proteins, signal transduction proteins, receptors

Question 2

What are the classes of proteins found at pre-synaptic sites?

Answer 2

-Proteins that help vesicles release neurotransmitter (release machinery)
-Vesicles are not proteins (they are sacs of membrane) but they have proteins sticking out of them
-Proteins that pump neurotransmitter or parts of neurotransmitter back into cells
-Calcium channels (you need calcium to release neurotransmitter)

Question 3

Nerve cells generate different types of electrical signals due to?

Answer 3

1) Differences in concentrations of specific ions (Anions/Cations) across the nerve cell membrane
2) Membranes are selectively permeable to different ions

Question 4

What is Ohm’s Law?

Answer 4

Relationship between current, voltage, and conductance

Question 5

What is potential (V)?

Answer 5

Electrical potential (potential per unit charge); The work needed to force charge between two points. Measured in Volts

Question 6

What is current (I)?

Answer 6

net flow of charge (ions); charge per unit time; measured in Amps.

Question 7

What is resistance (R)?

Answer 7

degree to which a material opposes current (Ohms); how much charge flow is impeded

Question 8

What is conductance (g)?

Answer 8

degree to which material allows current; ease of flow of current (Siemans)
Same thing, different views!

Question 9

Ohm’s Law equation

Answer 9

V=IR

Question 10

Increasing the voltage results in

Answer 10

Increased current

Question 11

Decreasing resistance (or increasing conductance) does what to the current?

Answer 11

Increases

Question 12

Extracellular recordings are:

Answer 12

Recording from the extracellular environment near a cell of interest

Question 13

Intracellular recordings are:

Answer 13

Recording from inside a cell of interest, piercing the membrane with an electrode

Question 14

What are patch clamp recordings?

Answer 14

Recording from the membrane of a cell of interest

Question 15

What tools are used to measure electrical signaling in neurons?

Answer 15

-Intracellular microelectrode (actually poke the cell and measure the inside; listen in to the chatter)
-Glass tubing with a very fine opening (1 um diameter) filled with a conductor (salt) and there is a wire (conductive core)
-Conductive core connected to a voltmeter (ei. Oscilloscope)
-Reference electrode
-Record transmembrane voltage

Question 16

Resting membrane potential has a reading of ?

Answer 16

-40 to -90 mV

Question 17

Membrane potential goes positive?

Answer 17

-DEPOLARIZED

Question 18

If Membrane potential goes negative?

Answer 18

-HYPERPOLARIZTION

Question 19

What are receptor potentials?

Answer 19

(due to activation of sensory neurons for example by external stimuli): transient changes are the first step in generating sensations

Question 20

What are synaptic potentials?

Answer 20

(between two neurons) EPSPs and IPSPs

Question 21

What are action potentials?

Answer 21

travel along long axons; boost signals; long range transmission

Question 22

How do neurons overcome not being good “electrical wires?” (Not good conductor, too long, leaky (lots of channels))

Answer 22

Booster system, Electrical signals produced by this system are ACTION POTENTIALS

Question 23

The Action Potential is a change from ____ to ____

Answer 23

negative, positive

Question 24

How long does an action potential take?

Answer 24

Brief approx. 1 ms

Question 25

True or False? Amplitude of the AP is independent of the magnitude used to evoke it

Answer 25

True

Question 26

True or False? Bigger stimulation leads to bigger action potentials

Answer 26

False

Question 27

True or False? Action Potentials are all- or none

Answer 27

True

Question 28

True or False? With bigger stimulation, you can get multiple APs (increase frequency) but they will be different amplitudes

Answer 28

False, With bigger stimulation, you can get multiple APs (increase frequency) but they will be the same amplitude

Question 29

Passive conduction ____ over distance

Answer 29

decays

Question 30

Active conduction is ___ over distance

Answer 30

constant

Question 31

How does Stimulus increase affect different types of electrical signals?

Answer 31

Stimulus Increase -APs increase in frequency, NOT in amplitude However…. -Receptor potentials, graded in proportion to the magnitude of the sensory stimulus -Synaptic potentials, amplitudes vary according to number of synapses activated EPSPs and IPSPs

Question 32

EPSP does what to the neuron ?

Answer 32

Depolarizes neuron

Question 33

IPSP does what to neuron ?

Answer 33

hyperpolarizes neuron

Question 34

Signals from other neurons?

Answer 34

produced by NT release at synapse

Question 35

Active transport and passive ion channels are responsible for what

Answer 35

ionic movements across membranes

Question 36

Active transporters do what

Answer 36

Actively move selected ions against concentration gradient, create ion concentration gradients

Question 37

What do ion channels allow?

Answer 37

Allow ions to diffuse down concentration gradient (OSMOSIS), selectively permeable to certain ions

Question 38

What is the movement of an ion

Answer 38

Electricity, movement of charge

Question 39

Neural function involves which 4 ions, all electrical events are based on movement of these ions in/out of the neuron

Answer 39

K, Na, Ca, Cl

Question 40

Ion channels are classified based on what

Answer 40

Ion selectivity, switch

Question 41

What are Voltage-gated channels important for?

Answer 41

important for action potential

Question 42

What are Ligand-gated channels important for ?

Answer 42

important for EPSPs

Question 43

What are stretch/pressure-gated channels important for ?

Answer 43

sensory neurons

Question 44

What are leak channels important for?

Answer 44

important for resting membrane potential

Question 45

True or False? Ion channels and transporters work against each other

Answer 45

True

Question 46

Transporters actively maintain _____ inside and _____ positive outside against concentration gradient

Answer 46

Negative, positive

Question 47

Ion channels allow osmosis to occur ______ concentration gradient

Answer 47

down

Question 48

Functional antagonism between ion channels and transporters help to generate

Answer 48

-Resting membrane potentials -Synaptic potentials/receptor potentials -Action potentials