Introduction to neurones, nerve conduction and synaptic transmission Flashcards Preview

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Flashcards in Introduction to neurones, nerve conduction and synaptic transmission Deck (48)
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1

What is the purpose of a dendrite?

To receive inputs from other neurones and convey graded electrical signals passively to the soma

2

What is the purpose of the soma?

It is the synthetic and metabolic centre
Contains the nucleus, ribosomes, mitochondria and ER
It integrates incoming electrical signals that are conducted passively to the axon hillock

3

What is the axon hillock?

Site of initiation of the "all or nothing" action potential

4

What is the function of the axon?

Conducts output signals as action potentials to the presynaptic terminal
Mediates transport of materials between the soma and presynaptic terminal and vice versa by slow and fast axonal transport

5

What is the function of the synapse?

Point of chemical communication between neurones

6

What viruses will exploit retrograde transport to infect neurones?

Herpes
Polio
Rabies

7

What are the different types of neurones?

Unipolar
Pseudounipolar
Bipolar
Multipolar

8

Where can unipolar neurones be found?

Peripheral autonomic system

9

Where can pseudounipolar neurones be found?

Dorsal root ganglion

10

Where can bipolar neurones be found?

Retina

11

Where can multipolar neurones be found?

Lower motor system

12

What is the resting potential for a neurone?

-70 mV

13

What is the threshold for a neurone?

-60 mV

14

What channels allow for the upstroke and downstroke of the action potential in neurones?

Upstroke = Na+
Downstroke = K+

15

Why do passive signals in neurones not spread far from their site of origin?

Current loss across the membrane accompanied by a reduced change in potential

16

What are strategies utilised to increase passive current speed and therefore action potential velocity?

Decreased axial resistance of the axoplasm via increased axon diameter
Increased membrane resistance - addition of myelin provided by schwann cells in PNS and oligodendrocytes in CNS

17

What is saltatory conduction?

Action potential jumping from one node of ranvier to the next

18

What are examples of demyelinating disorders?

MS (CNS)
Guillan-Barre (PNS)

19

What separates the pre and post synaptic membranes?

Synaptic cleft

20

What holds the pre and post synaptic membranes together?

A matrix of fibrous extracellular protein within the cleft

21

Where are the neurotransmitters stored in the neurone?

Vesicles within the presynaptic terminal

22

What are the different types of synapses?

Axodendritic
Axosomatic
Axoaxonic

23

What is the most common type of synapse?

Axodendritic

24

What is the most common neurotransmitter of excitatory synapses in the CNS?

Glutamate

25

What will glutamate activate?

Post synaptic, cation selective, inotropic glutamate receptors resulting in a depolarisation; excitatory postsynaptic potential

26

What are the major amino acid neurotransmitters in the CNS?

Glutamate
GABA
Glycine

27

What is the most common neurotransmitter of inhibitory synapses in the CNS?

GABA or glycine

28

What will GABA/glycine activate?

Postsynaptic, anion selective, inotropic, GABA or glycine receptors generating a local, graded hyperpolarizaing post synaptic potential

29

What is spatial summation?

Many inputs converge upon a neurone to determine its output

30

What is a temporal summation?

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