Test 1

Question 1

Mem excitability

Answer 1

The ability of a cell to generate action potentials. Depends on the presence of specific types of voltage gated ion channels

Question 2

Action potentials

Answer 2

Brief. Large changes in the electrical potential across the cell mem

Question 3

Channelopathies

Answer 3

Diseases caused by ion channel dysfunction

Question 4

Leak channels

Answer 4

Ion channels. Open in the testing unstimulated mem of the cell.

Question 5

Principle of electro neutrality

Answer 5

Both ic and ec fluid. Total mEq for cations equals total mEq for anions in the ic fluid. And in the ec fluid. There is no charge separation across the cell mem, no resting mem pot exists

Question 6

Mem polarization

Answer 6

Movement of ions down conc gradient resulting in net charge interior and exterior

Question 7

Mem pot

Answer 7

Mem voltage. Requires unequal distribution of ions across cell mem and open ion channels in the resting mem of the cell

Question 8

Equilibrium pot

Answer 8

Diffusion due to conc gradient is balanced by opp movement resulting from electrical pot

Question 9

Nernst eqn

Answer 9

Ek=(RT/zF)ln[(K+)o/(K+)i]

Ek=61mVlog[(K+)o/(K+)i]

Question 10

Goldman. Hodgkin. Katz. Eqn

Answer 10

Expanded versions of Nernst. Applicable to men with permeability to more than one ion. Vm=61mVlog[Pk(K+)o+Pna(Na+)o/Pk(K+)i+Pna(Na+)i]

Anions input opp due to -z

Question 11

Electrochemical gradient

Answer 11

Sum of the electrical gradient (total mem charge distribution) and the chemical (conc) gradient for the ion

Question 12

Hyper polarized

Answer 12

More negative. (Lowering Ko)

Question 13

Depolarizer

Answer 13

Less negative. (Raising Ko)

Question 14

Mem permeability (Pm)

Answer 14

How easily a substance can move through a mem

Question 15

Mem ion permeability

Answer 15

How easily an ion can move through a member. Determined by the number of open ion channels

Question 16

Mem conductance (gm)

Answer 16

How easily electric current flows through the cell mem. Units-Siemens (S). Electrical equivalent of permeability. Determined by the number of open channels in the cell mem. Gm=total number channels*single channel conductance

Question 17

Mem resistance (Rm)

Answer 17

Logical and mathematical inverse of conductance. R=1/g. Units-ohms

Question 18

Mem current (Im)

Answer 18

Rate of charge (ion) flow across the cell mem. Units-amperes,amps,A

Question 19

Driving force.

Answer 19

Net electrochemical force acting on an ion. Mem pot-ion equilibrium pot. Vion change=Vm-Eion

Question 20

Ohms Law

Answer 20

Current = driving force X conductance. V=IR

Question 21

Postsynaptic pot

Answer 21

Change in postsynaptic ion permeability caused by releases neurotransmitter

Question 22

Capacitance (Cm)

Answer 22

Cell mem capability to store electrical charge. Units-farads F. Directly related to SA of lipid bilateral of cell mem. Inversely proportional to mem thickness

Question 23

Length constant

Answer 23

The distance over which deltaVm declines by approximately 63% from the original level. Square root of Rm/Ra

Question 24

Axial R (Ra)

Answer 24

R to current flow down cylinder

Question 25

Capacitive current

Answer 25

Current flowing down the axon ahead of the action pot. Alters the charge stored in the mem capacitance.

Question 26

Orthodromic

Answer 26

Action pot propagated in normal direction from axon initial segment to axon terminal

Question 27

Antidromic

Answer 27

Action pot propagating backwards from axon terminal towards cell body. Not observed under physiological conditions

Question 28

Conduction velocity

Answer 28

Speed of action pot propagation.

Question 29

Use dependence

Answer 29

Bind to voltage gated Na+ channel s in open state to block

Question 30

Acetylcholine

Answer 30

Neurotransmitter at neuromuscular junction

Question 31

AChR

Answer 31

Neurotransmitter receptor present on muscle mem st NMJ

Question 32

Acetylccholineesterase

Answer 32

E present in synaptic cleft that breaks down ACh

Question 33

Active zone

Answer 33

Region of presynaptic mem where synaptic vesicles fuse and release ACh

Question 34

Agrin

Answer 34

Protein released from motor nerve that aggregates pre-existing AChRs on the muscle mem at the NMJ

Question 35

Dok7

Answer 35

Muscle specific activator of MuSK req for NMJ formation

Question 36

End plate current (EPC)

Answer 36

Flow of sodium ions through AChR tht occurs when ACh binds

Question 37

End plate pot (EPP)

Answer 37

Change in pot at the NMJ to more positive due to EPC

Question 38

Miniature end plate pot (MEPPs)

Answer 38

Small changes in muscle mem pot caused by spontaneous release of quanta of ACh

Question 39

LRP4

Answer 39

Low density lipoprotein receptor related protein 4. Binds to agrin and MuSK. Required for NMJ formation

Question 40

MuSK

Answer 40

Muscle specific kinase. When activated by agrin induces clustering of AChRs at NMJ by rapsyn

Question 41

Neuromuscular junction

Answer 41

NMJ. End plate

Question 42

Postjunctional fold

Answer 42

Invagination of muscle mem at NMJ

Question 43

Quanta

Answer 43

Vesicles containing ACh that are released and bind to AChRs even in the absence of nerve stimulation

Question 44

Rapsyn

Answer 44

Protein in muscle that binds to AChRs and clusters them at the NMJ

Question 45

Synaptic cleft

Answer 45

Area between motor nerve and muscle tht contains proteins involved in development and reg of NMJ