Lecture 3 - Cellular neurophysiology

Question 1

Na+ is concentrated on the ….. and K+ on the …..

Answer 1

outside, inside

Question 2

what pumps Na+ out of the cell and K+ in?

Answer 2

Na+/K+ ATPase pump

Question 3

which channels do K+ leave the cell via?

Answer 3

potassium leak channels

Question 4

what is the chemical gradient?

Answer 4

concentration difference between inside and outside of cell

Question 5

what is the electrical gradient?

Answer 5

ionic charge difference across the cell membrane

Question 6

how many Na+ are switched for how many K+ to increase the negative charge on the inside?

Answer 6

3 sodium for 2 potassium

Question 7

what does the nernst equation give?

Answer 7

the equilibrium potential of an ion present on both sides of a membrane

Question 8

name the equilibrium potentials of sodium potassium and chlorine in mV

Answer 8

potassium = -80mV
sodium = +60mV
chlorine = -65 mV

Question 9

what does the goldmann equation give?

Answer 9

summation of all the ion potentials to calculate resting membrane potential (-70mV)

Question 10

what do Z, F, T, R and E stand for in the nernst equation?

Answer 10

Z = ion charge/valency
F = faraday constant
T = absolute temp
R = gas constant
E = equilibrium potential

Question 11

what happens to the voltage gated sodium channels when the membrane potential reaches -55mv?

Answer 11

they open rapidly, sodium rushes into the cell causing further depolarization

Question 12

which state does the voltage gated sodium channel return to when sodium is pumped out of the cell causing repolarization?

Answer 12

closed state

Question 13

with voltage gated sodium channels:

open to inactivated = time…… (fast)
inactivated to closes = time …… (slow)

Answer 13

dependent

Question 14

what happens to the voltage gated postassium channels when the membrane potential reaches - 55mV?

Answer 14

they open slowly, K+ moves out of the cell causing repolarisation

Question 15

during hyperpolarization what happens to the voltage gated postassium channels?

Answer 15

opens slowly, K+ moves out of the cell and then the channels close slowly

Question 16

where do action potentials start in the neuron where there are many voltage gated sodium channels?

Answer 16

at the axon hillock

Question 17

the speed of movement of action potentials is dependent on which 2 things?

Answer 17

axon diameter and membrane resistance (myelination)

Question 18

multiple sclerosis occurs as a result of what structure on neurons being damaged?

Answer 18

myelin sheath

Question 19

name the 5 types of neurotransmitters

Answer 19

amino acids, amines, peptides, ATP and nitric oxide

Question 20

give 2 examples of amino acid neurotransmitters

Answer 20

glutamate and GABA

Question 21

give 3 examples of amine neurotransmitters

Answer 21

dopamine, noradrenaline, serotonin

Question 22

give 3 examples of peptide neurotransmitters

Answer 22

CRH, opiods, substance P

Question 23

what is the name of the proteins which mediate the fusion of vesicles to the PM during neurotransmission? which ion promotes the release of vesicles?

Answer 23

SNARE proteins, Ca2+

Question 24

what are the 2 major classes of neurotransmitter receptor?

Answer 24

ionotropic, metabotropic

Question 25

Ionotropic receptors:
- ions pass through the ……
- ……….. ion channels
- Can be ……. or inhibitory
- …….. signalling

Answer 25

receptor, ligand gated, excitatory, fast

Question 26

Metabotropic receptors
– a ……. messenger is required to signal
- …………. receptors
- …….-transmembrane structure
- Activate …….. events
- …….. signalling

Answer 26

2nd, G-protein coupled, 7, downstream, slower

Question 27

binding of neurotransmitter to a metabotropic causes the G protein to hydrolyse GDP to what?

Answer 27

GTP

Question 28

alpha and beta noradrenaline are what type of receptor?

Answer 28

g protein coupled

Question 29

GABA A has what type of receptor? GABA B has what type?

Answer 29

A = ligand gated ion channel
B = G protein linked

Question 30

selective serotonin reuptake inhibitors block what?

Answer 30

the uptake of serotonin

Question 31

monoamine oxidase inhibitors increase the content of what?

Answer 31

vesicles

Question 32

monoamine oxidase breaks down which neurotransmitter?

Answer 32

serotonin

Question 33

name two drugs of abuse which can cause non-impulse dependent (non-exocytotic) release of dopamine

Answer 33

amphetamine and MDMA