Introduction to the neurone L1

Question 1

do dendritic trees differ in the CNs>

Answer 1

yep

Question 2

Answer 2

Question 3

can you remember the nernst equation?

Answer 3

Question 4

At rest, the membrane is principally permeable to ___, so the resting potential is close to the __ Nernst potential.

Answer 4

At rest, the membrane is principally permeable to K+, so the resting potential is close to the K+ Nernst potential.

Question 5

internal chloride conc is ….

Answer 5

low

Question 6

the equilibrium potential for Chlorine is …..

Answer 6

negative

Question 7

teh equilibrium for calcium is

Answer 7

positive

Question 8

is chlorine actively extruded from the neurone?

what does this mean for the Cl- resting potential?

Answer 8

in most neurons, Cl- is also extruded by secondary active processes:

• coupled to K+
• and to the sodium- dependent influx of HCO3- ions

means cl- resting pot is more negative than the resting potential

Question 9

in wihcih neurones is intracellular Cl- raised?

Answer 9

In developing neurons (and adult olfactory receptor neurons) inward Na+/K+-coupled Cl- transport (NKCC1) raises intracellular chloride concentration so that opening of chloride channels at the resting potential instead allows an outward (excitatory) flow of chloride ions.

Question 10

how is Ca2+ powerfully extruded from the neurones?

Answer 10

1. an ATP-fuelled Ca2+ pump
2. secondary active transport via a sodium- calcium exchange,

Question 11

is calcium and intracellular messenger?

Answer 11

yep

Question 12

describe an Action potential

Answer 12

Question 13

what are gap junctions?

Answer 13

allow ions and small molecules to pass freely.

form of synapse

Question 14

problems with gap junctions compared to chemical synapses?

Answer 14

• require large presynaptic terminal
• almost all bidirectional
• no flexibiltiy by using differetn transmitters

Question 15

where are gap junctions used

Answer 15

normally used when it is necessary to synchronise the activity of large populations of cells, as in the developing embryo, or within the heart.

Question 16

vesicles of transmitter:

Fusion is induced by ………. proteins contained within the vesicle and presynaptic terminal membranes.

Answer 16

Fusion is induced by v-SNARE and t-SNARE proteins contained within the vesicle and presynaptic terminal membranes.

Question 17

whats the calcium sensory at the presynaptic terminal

Answer 17

The vesicle-associated protein synaptotagmin acts as the Ca2+ sensor.

Question 18

describe the process of exocytosis of the vesicle containing transmitter

Answer 18

• vesicle docks
• vesicle primed by close association between v and t SNAREs
• Calcium binds synaptotagmin
• membranes fuse

Question 19

3 criteria for a neurotransmitter

Answer 19

1. must be present within the presynaptic terminal, or mechanisms exist for its synthesis.
2. Second, it must be released in adequate quantity on stimulation.
3. Finally, added transmitter must have the same effect as stimulation.

Question 20

Neurotransmitters can act either directly on _______ receptors which are themselves ionic channels, or indirectly on ________ receptors which achieve their effects via second messenger cascades.

Answer 20

Neurotransmitters can act either directly on ionotropic receptors which are themselves ionic channels, or indirectly on metabotropic receptors which achieve their effects via second messenger cascades.

Question 21

gaps

Answer 21

Question 22

glutamate, the primary ____ transmitter in the CNS

Answer 22

glutamate, the primary excitatory transmitter in the CNS

Question 23

GABA and glycine, the major ______ transmitters in brain and spinal cord.

Answer 23

GABA and glycine, the major inhibitory transmitters in brain and spinal cord.

Question 24

advantages of ionotropic receptors?

Answer 24

1. rapid
2. some cases - allow Ca2+ influx

Question 25

The most important excitatory ionotropic receptors in the CNS are those which respond to the amino acid transmitter ______.

Answer 25

The most important excitatory ionotropic receptors in the CNS are those which respond to the amino acid transmitter glutamate.

Question 26

There are two distinct classes of ionotropic glutamate receptor

what are they

Answer 26

There are two distinct classes of ionotropic glutamate receptor: NMDA and non-NMDA receptors

Question 27

non-NMDA receptors can divide into….. (another 2 subcategories)

Answer 27

divide into into AMPA and kainate receoptors

Question 28

describe AMPA current voltage relationship

Answer 28

linear - ohmic.

mostly impermeable to divalent cations

Question 29

are NMDA receptors permeable to Ca2+?

Answer 29

yep

Question 30

are NMDA receptors permeable to Ca2+ at negative potentials?

Answer 30

at negative potentials they are blocked by extracellular Mg2+ ions trying to enter the channel.

When the membrane is depolarized this block is relieved, so that Na+ and Ca2+ ions can pass through the channel.

Question 31

label

Answer 31

Question 32

label regarding NMDA receptors

Answer 32

Question 33

big advantage of metabotropic receptors?

Answer 33

amplification

lots of 2nd messenger molecules

Question 34

g protein

Answer 34

Question 35

adenylyl cyclase response + others

Answer 35

Question 36

Nitric oxide acts directly on its effector enzyme, …..

Answer 36

Nitric oxide acts directly on its effector enzyme, soluble guanylyl cyclase.

Question 37

obvious

Answer 37

Question 38

fat

Answer 38

mamba