Introduction to Neurones, Nerve Conduction & Synaptic Transmission Flashcards Preview

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Flashcards in Introduction to Neurones, Nerve Conduction & Synaptic Transmission Deck (35):
1

what is the role of dendrites?

receives inputs and convey graded electrical signals passively to soma

2

what does the cell body (soma) contain?

nucleus
ribosomes
mitochondria
endoplasmic reticulum (Nissi substance)

3

what is the role of the cell body (soma)?

integrates incoming electrical signals that are conducted passively to axon hillock

4

what is the role of the axon hillock?

site of initiation of action potential

5

what is the role of the axon?

conducts output signals as action potentials to presynaptic terminal

6

what is the role of the synapse?

point of communication between neurones

7

give examples of the following types of neurones:
a) unipolar?
b) pseudounipolar?
c) bipolar?
d) multipolar?

a) unipolar - peripheral autonomic neurone

b) pseudounipolar - dorsal root ganglion neurone

c) bipolar - retinal bipolar neurone

d) multipolar - low motor neurone

8

what causes upstroke of action potential?

influx of Na+ via voltage activated Na+ channel

9

what causes downstroke of action potential?

efflux of K+ via voltage activated K+ channel

10

what does the term "overshoot" mean in relation to action potential?

very brief period when polarity is reversed to inside positive

11

what is the consequence of a nerve cell membrane being leaky (not perfect insulator)?

passive signals do not spread far from their site of origin due to current loss across membrane accompanied by reduced change in potential

12

what does the distance travelled by membrane depend on?

membrane resistance - rm - (this needs to be high)

axial resistance - ri - (this needs to be low)

13

what can increase passive current spread and therefore AP velocity?

decrease ri (possible by increasing axon diameter)

increase rm (by adding myelin)

14

what provides myelin in the PNS and CNS?

schwann cells in PNS
oligodendrocytes in CNS

15

where is conduction faster - myelinated or non-myelinated axons?

myelinated

16

what is the name of the demyelination condition in:
a) CNS?
b) PNS?

a) multiple sclerosis
b) gullian-barre

17

what is the membrane difference between pre synaptic and post synaptic membranes?

pre synaptically = active zones around which vesicles cluster

post synaptically = post synaptic density containing neurotransmitter receptors

18

what is the most common type of synapse (classified by location of presynaptic terminal upon post synaptic cell)?

axodendritic

axosomatic (common) and axoaxonic (less common) are also types

19

what is example of neurotransmitter which elicits excitatory synapse?

glutamate

(depolarising response)

20

what is example of neurotransmitter that elicits inhibitory synapse?

y-aminobutyric acid (GABA)

glycine

(hyperpolarising response)

21

what is meant by spatial summation?

many inputs converge upon a neurone to determine its output

22

what is meant by temporal summation?

a single input may modulate output by variation in action potential frequency of that input

23

where are acetylcholine, amino acids and amines released from?

synaptic vesicles

24

where are peptides released from?

secretory vesicles

25

what neurotransmitters activate ionotrophic ligand-gated ion channels (LGICs) and thus mediate fast transmission?

glutamate
GABA
glycine
acetylcholine
5-HT

26

which neurotransmitters activate metabotropic GPCR and thus mediate slow transmission?

all except glycine

27

what of ionotrophic receptors and metabotropic GCPR are direct / indirect gating?

ionotrophic = direct (receptor is integral component of molecule that forms channel it controls)

metabotropic = indirect (receptor and channel it controls are distinct)

28

give examples of amino acids in the CNS?

glutamate
GABA
glycine

29

give examples of amines in CNS?

dopamine
histamine
noradrenaline
serotonin

30

give examples of peptides in CNS?

CCK
dysnorphin
ENK
neuropeptide Y
somatostatin
substance P
TRH
VIP

31

what is the difference in speed of transmission in ligand gated ion channel receptors and GPCR?

ionotrophic ligand-gated ions mediate fast neurotransmission

GPCR mediate slow neurotransmission

32

describe the structure of ionotropic LGIC receptors vs that of metabotropic receptors?

ionotropic receptor for neurotransmitter is itself a channel

metabotropic receptors bind neurotransmitter and then signal to other G proteins etc to open a channel to let ions in

33

if glutamate has both ionotropic and metabotropic receptors on post-synaptic membrane, what kind of response does this create?

a fast and slow EPSP are generated from each of channels respectively

34

what types of ionotropic receptors can glutamate bind to and activate an ion channel?

AMPA
kainic acid
(collectively non-NMDA)

NMDA

35

how do the responses of each ionotropic glutamate receptor differ?

AMPA - large but transient AP

NMDA - smaller and slower AP